U.S. patent application number 12/800500 was filed with the patent office on 2011-05-12 for inhibitors of cognitive decline.
Invention is credited to Hiromi Arai, Kristin Beierle, Cody Lee Fullenwider, Zoya Kai, Gilbert M. Rishton.
Application Number | 20110111068 12/800500 |
Document ID | / |
Family ID | 39269109 |
Filed Date | 2011-05-12 |
United States Patent
Application |
20110111068 |
Kind Code |
A1 |
Rishton; Gilbert M. ; et
al. |
May 12, 2011 |
Inhibitors of cognitive decline
Abstract
Compounds that are central nervous system drug candidates for
the treatment of cognitive decline and, more particularly,
Alzheimer's disease are provided. Methods of treating, inhibiting,
and/or abatement of cognitive decline and Alzheimer's disease with
a derivative of ginger oil are also provided. Also provided is a
method of conditioning biological extracts, such as a medicinal
plant extract, by a reductive amination process to give
nitrogen-containing derivatives.
Inventors: |
Rishton; Gilbert M.;
(Malibu, CA) ; Arai; Hiromi; (Simi Valley, CA)
; Kai; Zoya; (La Jolla, CA) ; Fullenwider; Cody
Lee; (Ojai, CA) ; Beierle; Kristin; (Thousand
Oaks, CA) |
Family ID: |
39269109 |
Appl. No.: |
12/800500 |
Filed: |
May 17, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
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11863549 |
Sep 28, 2007 |
7723377 |
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12800500 |
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60827630 |
Sep 29, 2006 |
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Current U.S.
Class: |
424/756 ; 506/23;
514/408; 514/654; 548/574; 548/579; 564/374; 564/509 |
Current CPC
Class: |
A61P 25/00 20180101;
C07C 217/64 20130101; C07D 207/04 20130101; C07D 207/08 20130101;
A61P 25/28 20180101 |
Class at
Publication: |
424/756 ; 506/23;
514/408; 514/654; 548/574; 548/579; 564/374; 564/509 |
International
Class: |
A61K 36/906 20060101
A61K036/906; C40B 50/00 20060101 C40B050/00; A61K 31/40 20060101
A61K031/40; A61K 31/135 20060101 A61K031/135; C07D 207/04 20060101
C07D207/04; C07D 295/02 20060101 C07D295/02; C07C 211/00 20060101
C07C211/00; A61P 25/00 20060101 A61P025/00; A61P 25/28 20060101
A61P025/28 |
Claims
1. A method of inhibiting, treating, or abatement of cognitive
decline in a mammal, the method comprising administering a
derivative of ginger oil to a mammal.
2. A method according to claim 1 wherein a symptom of the cognitive
decline is one or more of memory loss, confusion, impaired
judgment, personality changes, disorientation, and loss of language
skills.
3. A method according to claim 1 wherein the treating or abatement
of the cognitive decline comprises restoration of long term
potentiation.
4. A method according to claim 1 wherein the inhibiting, treating,
or abatement of cognitive decline comprises inhibiting, treating,
or abatement of one or both of neurodegeneration and general
amyloidosis.
5. A method according to claim 1 wherein the inhibiting, treating,
or abatement of cognitive decline comprises inhibiting, treating,
or abatement of one or more of amyloid production, amyloid
assembly, amyloid aggregation, amyloid oligomer binding, and
amyloid deposition.
6. A method according to claim 1 wherein the derivative of ginger
oil is a compound in purified and isolated form.
7. A method of inhibiting, treating, or abatement of Alzheimer's
disease in a mammal, the method comprising administering a
derivative of ginger oil to a mammal.
8. A compound of the formula: ##STR00064## or a pharmaceutically
acceptable salt or prodrug thereof, wherein, R.sub.1 and R.sub.2
are each independently selected from the group consisting of
hydrogen, hydroxy, methoxy, halide, haloalkyl, small alkyl, and
small alkoxy; R.sub.3, R.sub.4 and R.sub.5 are each independently
selected from the group consisting of hydrogen, small alkyl,
cycloalkyl, heterocyclyl, heterocyclylalkyl, aryl, arylalkyl,
heteroaryl, and heteroarylalkyl; R.sub.6 and R.sub.7 are each
independently selected from the group consisting of hydrogen, small
alkyl, hydroxyalkyl, cycloalkyl, heterocyclyl, heterocyclylalkyl,
aryl, arylalkyl, heteroaryl, and heteroarylalkyl; or R.sub.6 and
R.sub.7 along with the nitrogen to which they are attached form a
five or six membered heterocyclic ring, comprising one or two
heteroatoms selected from the group consisting of oxygen, sulfur
and nitrogen, wherein the five or six membered heterocyclic ring is
unsubstituted, or substituted with a substituent selected from the
group consisting of hydroxy, hydroxyalkyl, halide, haloalkyl, small
alkyl, small alkoxy, and --CH.sub.2OR.sub.9; R.sub.8 is selected
from the group consisting of hydroxy, small alkoxy, and
--NR.sub.10R.sub.11; R.sub.9 is selected from the group consisting
of hydrogen, small alkyl, cycloalkyl, heterocyclyl,
heterocyclylalkyl, aryl, arylalkyl, heteroaryl, and
heteroarylalkyl; R.sub.10 and R.sub.11 are each independently
selected from the group consisting of hydrogen, small alkyl,
hydroxyalkyl, cycloalkyl, heterocyclyl, heterocyclylalkyl, aryl,
arylalkyl, heteroaryl, and heteroarylalkyl; or R.sub.10 and
R.sub.11 along with the nitrogen to which they are attached form a
five or six membered heterocyclic ring, comprising one or two
heteroatoms selected from the group consisting of oxygen, sulfur
and nitrogen, wherein the five or six membered heterocyclic ring is
unsubstituted, or substituted with a substituent selected from the
group consisting of hydroxy, hydroxyalkyl, halide, haloalkyl, small
alkyl, small alkoxy, and --CH.sub.2OR.sub.9; R.sub.12 is selected
from the group consisting of hydrogen, haloalkyl, and small alkyl;
R.sub.13 is selected from the group consisting of hydrogen, and
small alkyl; R.sub.14 is selected from the group consisting of
hydrogen, and small alkyl; R.sub.15 and R.sub.16 are each
independently selected from the group consisting of hydrogen, small
alkyl, cycloalkyl, heterocyclyl, heterocyclylalkyl, aryl,
arylalkyl, heteroaryl, and heteroarylalkyl; and n, m, and p are
each independently 0, 1, or 2.
9. A compound according to claim 8 of the formula: ##STR00065## or
a pharmaceutically acceptable salt or prodrug thereof.
10. A compound according to claim 9 of the formula: ##STR00066## or
a pharmaceutically acceptable salt or prodrug thereof, wherein,
R.sub.6 and R.sub.7 along with the nitrogen to which they are
attached form a five or six membered heterocyclic ring of the
formula: ##STR00067## wherein, X is selected from the group
consisting of --CH.sub.2, --CHR.sub.11, --N.dbd., --O--, --S--, and
--N--R.sub.17, wherein each carbon atom of the five or six membered
heterocyclic ring, individually, is unsubstituted, or substituted
with a substituent selected from the group consisting of hydroxy,
hydroxyalkyl, halide, haloalkyl, small alkyl, small alkoxy, and
--CH.sub.2OR.sub.9; and R.sub.17 is selected from the group
consisting of hydrogen, small alkyl, hydroxyalkyl, cycloalkyl,
heterocyclyl, heterocyclylalkyl, aryl, arylalkyl, heteroaryl, and
heteroarylalkyl.
11. A compound according to claim 8 of the formula: ##STR00068## or
a pharmaceutically acceptable salt or prodrug thereof, wherein,
R.sub.18 is selected from the group consisting of hydrogen,
hydroxy, hydroxyalkyl, halide, haloalkyl, small alkyl, small
alkoxy, and --CH.sub.2OR.sub.9.
12. A compound according to claim 11 of the formula: ##STR00069##
or a pharmaceutically acceptable salt or prodrug thereof.
13. A compound according to claim 8 of the formula: ##STR00070## or
a pharmaceutically acceptable salt or prodrug thereof.
14. A compound according to claim 12 of the formula: ##STR00071##
or a pharmaceutically acceptable salt or prodrug thereof.
15. A compound according to claim 8 of the formula: ##STR00072## or
a pharmaceutically acceptable salt or prodrug thereof.
16. A compound according to claim 15 of the formula: ##STR00073##
or a pharmaceutically acceptable salt or prodrug thereof, wherein,
R.sub.14, R.sub.15 and R.sub.16 are each independently small alkyl;
n and m are each independently 0 or 1; and p is 1 or 2.
17. A compound according to claim 16 of the formula: ##STR00074##
or a pharmaceutically acceptable salt or prodrug thereof.
18. A compound according to claim 8 wherein the compound exhibits
activity in a beta-secretase assay.
19. A composition comprising a compound according to claim 8 in a
pharmaceutically-acceptable carrier.
20. A method of inhibiting, treating, or abatement of cognitive
decline comprising the administration of a compound of claim 8 to a
patient.
21. A method according to claim 20 wherein the method of
inhibiting, treating, or abatement of cognitive decline comprises
inhibiting, treating, or abatement of one or more symptoms of
cognitive decline including memory loss, confusion, impaired
judgment, personality changes, disorientation, and loss of language
skills.
22. A method according to claim 20 wherein the method of
inhibiting, treating, or abatement of cognitive decline comprises
restoration of long term potentiation.
23. A method according to claim 20 wherein the inhibiting,
treating, or abatement of cognitive decline comprises inhibiting,
treating, or abatement of neurodegeneration and general
amyloidosis.
24. A method according to claim 20 wherein the inhibiting,
treating, or abatement of cognitive decline comprises inhibiting,
treating, or abatement of one or more of amyloid production,
amyloid assembly, amyloid aggregation, amyloid oligomer binding,
and amyloid deposition.
25. A method of inhibiting, treating, or abatement of Alzheimer's
disease comprising the administration of a compound of claim 8 to a
patient.
26. A method of preparing an array of chemical compounds from a
biological extract, the method comprising: providing a biological
extract, the biological extract having one or more biological
compounds, each biological compound having one or more reactive
electrophilic groups: reacting the biological compounds with an
amine to incorporate the amine into the biological compounds: and
reacting the biological compound having the incorporated amine with
a reducing agent to form an array of one or more chemical
compounds, wherein the one or more chemical compounds are
derivatives of the biological compounds in the biological
extract.
27. A method according to claim 26 further comprising isolating one
or more of the chemical compounds.
28. A method according to claim 27 further comprising isolating one
or more of the chemical compounds in a purified form.
29. A method according to claim 26 further comprising screening one
or more of the chemical compounds for biological activity.
30. A method according to claim 26 wherein the biological extract
is a plant extract.
Description
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application claims priority of U.S. Provisional
Patent Application 60/827,630 titled "Unnatural Beta-Secretase
Inhibitors Derived From Conditioned Extraction of Ginger Root,"
filed Sep. 29, 2006, the entire contents of which is hereby
incorporated herein by reference.
BACKGROUND
[0002] Cognitive decline, such as memory loss, confusion, impaired
judgment, personality changes, disorientation, and loss of language
skills occurs in much of the population as they age, in varying
degree. The most common, severe and irreversible form of cognitive
decline is Alzheimer's disease, which, at present, is always
fatal.
[0003] The symptoms of cognitive decline and Alzheimer's disease
are thought to stem from the formation of amyloid plaques and
neurofibrillary tangles, which are thought to contribute to the
degradation of the neurons (nerve cells) in the brain and the
subsequent onset of symptoms. Amyloid is a general term for protein
fragments that the body produces normally. Beta-amyloid is a
fragment of a protein that is snipped from another protein called
amyloid precursor protein (APP). In a healthy brain, beta-amyloid
protein fragments are broken down and eliminated. In individuals
with Alzheimer's disease and other forms of cognitive decline, the
fragments accumulate to form hard, insoluble plaques.
Neurofibrillary tangles are insoluble twisted fibers that are found
inside of the brain's cells. The protein contained in
neurofibrillary tangles, i.e., the tau protein, forms a
microtubule, which helps transport nutrients and other important
substances from one part of the nerve cell to another. In
Alzheimer's disease the tau protein is abnormal and the microtubule
structures collapse.
[0004] Beta-secretase is the enzyme in the human brain responsible
for the production of Beta-amyloid, the pathogenic substance
responsible for the formation of brain plaques and tangles in the
Alzheimer's diseased brain. See, e.g., Citron et al., Proc. Natl.
Acad. Sci., USA (1996) 93(23): 13170-13175. Beta-amyloid and its
oligomers are also believed to be responsible for early cognitive
decline in the pre-Alzheimer's diseased brain. Inhibition of
beta-secretase would be expected to lessen beta-amyloid burden in
the brain and thus slow cognitive decline, block the formation of
amyloid oligomers, the production of plaques and tangles, halt
neurodegeneration, and to potentially treat mild cognitive
impairment and more serious forms of cognitive impairment such as
Alzheimer's disease.
[0005] The gingerols are a series of natural small molecules
isolated from ginger, Zingiber officinale, and are classified
according to their alkyl chain length e.g., [6]-gingerol,
[8]-gingerol. Gingerols are known to be relatively unstable under
both chemical and biological conditions, forming inactive
substances. For example, the beta-hydroxycarbonyl function of the
gingerols is vulnerable to oxidation or dehydration to form
inactive products, and the gingerols are particularly prone to
rapid dehydration under acidic conditions, such that even the pure
substance is difficult to store for long periods. Further
information on gingerols can be found in, for example, Deniff et
al., J. Chem. Soc. Perkin 1, 1981, 82-87; Mustafa, et al., J. Drug
Dev., 1993, 6, 25-39; and Young-Joon et al., Life Sciences, 1994,
54, PL 321-326. Accordingly, simple oral dosing of the gingerols
for medicinal action might not be possible due to the acidic
environment of the stomach and upper intestinal tract. Further,
chemical and biological instability is also likely to be a serious
problem for intravenous doses. Accordingly, there is strong need to
discover inhibitors of cognitive decline, and in particular,
compounds that are useful in the treatment and abatement of
cognitive decline and Alzheimer's disease, by methods such as
inhibiting amyloid production, aggregation, and/or deposition
(i.e., plaqing), inhibiting neuorodegeneration, and/or restoring
long term potentiation. There is also a need for inhibitors of
cognitive decline that are chemically and biologically stable.
[0006] Plants have attracted relatively little attention as
potentially valuable resources for drug discovery in the area of
cognitive decline and Alzheimer's disease. The use of plant
extracts to produce unnatural derivatives of compounds of medicinal
interest is not generally used. Accordingly, there is also a need
for a method of producing compounds of medicinal interest from
plant extracts and extracts from other biological sources. In
particular, there is also a need to produce and identify compounds
derived from plant extracts that are useful in the treatment and
abatement of cognitive decline and Alzheimer's disease.
SUMMARY
[0007] The present invention satisfies the above identified needs.
According to the present invention, compounds useful for
inhibiting, treating, or abatement of cognitive decline are
provided. In a method called "chemical conditioning", the compounds
of the present invention are derived from naturally occurring
compounds, such as those found in medicinal plants, like ginger.
The chemical conditioning process described herein is applicable to
a large variety of biological extracts and may be used to create
compound arrays for screening for potential new drug candidates.
Further, in general, compounds derived by the chemical conditioning
process are chemically stable and structurally diverse, and good
candidates for use in drug screenings for pharmaceutical
activity.
[0008] According to one embodiment of the invention, compounds
derived from ginger oil are provided. The compounds show activity
in a beta-secretase assay and are potentially useful for the
inhibition, treatment, and abatement of cognitive decline and
Alzheimer's disease. Preferably, the derivatives of ginger oil are
nitrogen containing, and more preferably, the derivative of ginger
oil is compound in purified and isolated form. The compounds and
methods described herein may be used to treat one or more symptoms
of cognitive decline and/or Alzheimer's disease such as memory
loss, confusion, impaired judgment, personality changes,
disorientation, and loss of language skills. Further, the compounds
and methods described herein may be useful in inhibiting, treating,
and/or abating cognitive decline and/or Alzheimer's disease by
restoring long term potentiation, and/or inhibiting, treating, or
abatement of one or both of neurodegeneration and general
amyloidosis, more specifically, by inhibiting, treating, or
abatement of one or more of amyloid production, amyloid assembly,
amyloid aggregation, amyloid oligomer binding, and amyloid
deposition.
[0009] According to another embodiment of the invention, compounds
derived from ginger oil by the chemical conditioning process
described herein are provided. Preferably, compounds according to
the present invention are compounds of Formulas I, II, and III:
##STR00001##
and pharmaceutically acceptable salts and prodrugs thereof,
wherein,
[0010] R.sub.1 and R.sub.2 are each independently selected from the
group consisting of hydrogen, hydroxy, methoxy, halide, haloalkyl,
small alkyl, and small alkoxy;
[0011] R.sub.3, R.sub.4 and R.sub.5 are each independently selected
from the group consisting of hydrogen, small alkyl, cycloalkyl,
heterocyclyl, heterocyclylalkyl, aryl, arylalkyl, heteroaryl, and
heteroarylalkyl;
[0012] R.sub.6 and R.sub.7 are each independently selected from the
group consisting of hydrogen, small alkyl, hydroxyalkyl,
cycloalkyl, heterocyclyl, heterocyclylalkyl, aryl, arylalkyl,
heteroaryl, and heteroarylalkyl; or R.sub.6 and R.sub.7 along with
the nitrogen to which they are attached form a five or six membered
heterocyclic ring, comprising one or two heteroatoms selected from
the group consisting of oxygen, sulfur and nitrogen, wherein the
five or six membered heterocyclic ring is unsubstituted, or
substituted with a substituent selected from the group consisting
of hydroxy, hydroxyalkyl, halide, haloalkyl, small alkyl, small
alkoxy, and --CH.sub.2OR.sub.9;
[0013] R.sub.8 is selected from the group consisting of hydroxy,
small alkoxy, and --NR.sub.10R.sub.11;
[0014] R.sub.9 is selected from the group consisting of hydrogen,
small alkyl, cycloalkyl, heterocyclyl, heterocyclylalkyl, aryl,
arylalkyl, heteroaryl, and heteroarylalkyl;
[0015] R.sub.10 and R.sub.11 are each independently selected from
the group consisting of hydrogen, small alkyl, hydroxyalkyl,
cycloalkyl, heterocyclyl, heterocyclylalkyl, aryl, arylalkyl,
heteroaryl, and heteroarylalkyl; or R.sub.10 and R.sub.11 along
with the nitrogen to which they are attached form a five or six
membered heterocyclic ring, comprising one or two heteroatoms
selected from the group consisting of oxygen, sulfur and nitrogen,
wherein the five or six membered heterocyclic ring is
unsubstituted, or substituted with a substituent selected from the
group consisting of hydroxy, hydroxyalkyl, halide, haloalkyl, small
alkyl, small alkoxy, and --CH.sub.2OR.sub.9;
[0016] R.sub.12 is selected from the group consisting of hydrogen,
haloalkyl, and small alkyl;
[0017] R.sub.13 is selected from the group consisting of hydrogen,
and small alkyl;
[0018] R.sub.14 is selected from the group consisting of hydrogen,
and small alkyl;
[0019] R.sub.15 and R.sub.16 are each independently selected from
the group consisting of hydrogen, small alkyl, cycloalkyl,
heterocyclyl, heterocyclylalkyl, aryl, arylalkyl, heteroaryl, and
heteroarylalkyl; and
[0020] n, m, and p are each independently 0, 1, or 2.
Preferably, compounds according to Formula I include the compounds
of the formula:
##STR00002##
and pharmaceutically acceptable salts and prodrugs thereof,
wherein,
[0021] R.sub.6 and R.sub.7 along with the nitrogen to which they
are attached form a five or six membered heterocyclic ring of the
formula:
##STR00003##
wherein,
[0022] X is selected from the group consisting of --CH.sub.2,
--CHR.sub.17, --N.dbd., --O--, --S--, and --N--R.sub.17, wherein
each carbon atom of the five or six membered heterocyclic ring,
individually, is unsubstituted, or substituted with a substituent
selected from the group consisting of hydroxy, hydroxyalkyl,
halide, haloalkyl, small alkyl, small alkoxy, and
--CH.sub.2OR.sub.9; and
[0023] R.sub.17 is selected from the group consisting of hydrogen,
small alkyl, hydroxyalkyl, cycloalkyl, heterocyclyl,
heterocyclylalkyl, aryl, arylalkyl, heteroaryl, and
heteroarylalkyl.
More preferably, compounds according to Formula I include compounds
of the formula:
##STR00004##
and pharmaceutically acceptable salts and prodrugs thereof,
wherein,
[0024] R.sub.18 is selected from the group consisting of hydrogen,
hydroxy, hydroxyalkyl, halide, haloalkyl, small alkyl, small
alkoxy, and --CH.sub.2OR.sub.9.
[0025] Preferred compounds according to Formula III include
compounds of the formula:
##STR00005##
and pharmaceutically acceptable salts and prodrugs thereof,
wherein,
[0026] R.sub.14, R.sub.15 and R.sub.16 are each independently small
alkyl;
[0027] n and m are each independently 0 or 1; and
[0028] p is 1 or 2.
[0029] Most preferably, compounds according to Formulas I, II, and
II include the compounds shown in FIG. 3, and pharmaceutically
acceptable salts and prodrugs thereof. Also most preferably,
compounds according to the present invention exhibit activity in a
beta-secretase assay.
[0030] In another embodiment, the invention comprises a compound
according to Formula I, II, and/or III in a
pharmaceutically-acceptable carrier.
[0031] In another embodiment, the invention comprises a method of
inhibiting, treating, or abatement of cognitive decline and/or
Alzheimer's disease comprising the administration of a compound
according to Formula I, II, and/or III to a patient.
[0032] In another embodiment, the invention comprises a method of
preparing an array of chemical compounds from a biological extract.
According to the method, a biological extract is provided. The
biological extract has one or more biological compounds, and each
biological compound has one or more reactive electrophilic groups.
Preferably, the biological extract is a plant extract, and/or the
reactive electrophilic group is an aldehyde or a ketone. Then, the
biological compounds in the extract are reacted with an amine to
incorporate the amine into the biological compounds. The biological
compounds having the incorporated amine are then reacted with a
reducing agent to form an array of one or more chemical compounds.
The one or more chemical compounds are derivatives of the
biological compounds in the biological extract. Preferably, the
biological compounds are nitrogen-containing. The chemical
compounds may then be isolated and/or purified, and screened for
biological activity. More preferably, the chemical compounds are
derived from a plant extract and are screened for biological
activity.
FIGURES
[0033] These and other features, aspects and advantages of the
present invention will become better understood from the following
description, appended claims, and accompanying figures where:
[0034] FIG. 1 shows exemplary and isolated aromatic compounds of
the invention for the treatment of cognitive impairment and
Alzheimer's disease.
[0035] FIG. 2 shows exemplary and isolated non-aromatic compounds
of the invention for the treatment of cognitive impairment and
Alzheimer's disease; and
[0036] FIG. 3 shows isolated compounds of the invention having
superior activity in a beta-secretase assay for the treatment of
cognitive impairment and Alzheimer's disease.
DETAILED DESCRIPTION
[0037] The present invention provides a method of inhibiting,
treating, or abatement of cognitive decline, comprising
administering a nitrogen-containing derivative of ginger oil to a
subject, i.e., a mammal. Also, the present invention provides
compounds that are nitrogen-containing derivatives of ginger oil.
The compounds of the present invention show activity in a
beta-secretase assay and are potentially useful as a therapeutic
agent for the treatment and prevention of Alzheimer's disease, and
for the treatment of the symptoms of cognitive decline, such as
memory loss, confusion, impaired judgment, personality changes,
disorientation, or loss of language skills, by, for example,
inhibiting, treating, or the abatement of one or more of amyloid
production, amyloid aggregation, and amyloid deposition. In
addition, the compounds of the present invention may be used for
inhibiting, treating, or abatement of neurodegeneration and general
amyloidosis, and may be used for treating, and/or the abatement of
cognitive decline such as by the restoration of long term
potentiation.
[0038] In another aspect, the present invention provides a two step
reductive amination process for preparing a derivative of a
biological extract, such as a medicinal plant extract. This method
has wide-ranging applications in the field of drug discovery using
common and medicinal plants. This method has been employed in the
present invention for the discovery of beta-secretase inhibitors
derived from the extract of ginger root.
[0039] For the purpose of this disclosure, the following terms have
the following meanings.
[0040] The term "small alkoxy" as used herein refers to a small
alkyl group attached to the parent molecular group through an
oxygen atom. Examples of alkoxy groups include methoxy, ethoxy,
isopropoxy, and t-butoxy.
[0041] The term "small alkyl" as used herein refers to a saturated
straight or branched chain group of 1-8 carbon atoms derived from
an alkane by the removal of one hydrogen atom. Examples of alkyl
groups include methyl, ethyl, n-propyl, isopropyl and t-butyl.
[0042] The term "aryl" as used herein refers to a mono- or bicyclic
carbocyclic ring system having one or two aromatic rings. The aryl
group can also be fused to a cyclohexane, cyclohexene, cyclopentane
or cyclopentene ring. The term "aryl" is also indended to encompass
the term "phenyl", i.e., a monocyclic carbocyclic ring system
having one aromatic ring.
[0043] The term "arylalkyl" as used herein refers to an aryl group
attached to the parent molecular group through an alkyl group.
[0044] The term "cycloalkyl" as used herein refers to a monovalent
saturated cyclic or bicyclic hydrocarbon group of 3-12 carbons
derived from a cycloalkane by the removal of a single hydrogen
atom.
[0045] The term "cycloalkylalkyl" as used herein refers to a
cycloalkyl group attached to the parent molecular group through an
alkyl group.
[0046] The terms "halo" or "halogen" as used herein refers to F,
Cl, Br, or I.
[0047] The term "haloalkyl" as used herein refers to a small alkyl
group substituted with one or more halogen atoms.
[0048] The terms "heterocycle" and "heterocyclyl", represent a 5-,
6- or 7-membered ring containing one, two or three heteroatoms
independently selected from the group consisting of nitrogen,
oxygen and sulfur. The 5-membered rings have zero to two double
bonds and the 6- and 7-membered rings have zero to three double
bonds. The term "heterocycle" or "heterocyclyl" as used herein
additionally refers to bicyclic, tricyclic and tetracyclic groups
in which any of the above heterocyclic rings is fused to one or two
rings independently selected from an aryl ring, a cyclohexane ring,
a cyclohexene ring, a cyclopentane ring, a cyclopentene ring or
another monocyclic heterocyclic ring. Examples of heterocycles
include acridinyl, benzimidazolyl, benzofuryl, benzothiazolyl,
benzothienyl, benzoxazolyl, biotinyl, cinnolinyl, dihydrofuryl,
dihydroindolyl, dihydropyranyl, dihydrothienyl, dithiazolyl, furyl,
homopiperidinyl, imidazolidinyl, imidazolinyl, imidazolyl, indolyl,
isoquinolyl, isothiazolidinyl, isothiazolyl, isoxazolidinyl,
isoxazolyl, morpholinyl, oxadiazolyl, oxazolidinyl, oxazolyl,
piperazinyl, piperidinyl, pyranyl, pyrazolidinyl, pyrazinyl,
pyrazolyl, pyrazolinyl, pyridazinyl, pyridyl, pyrimidinyl,
pyrimidyl, pyrrolidinyl, pyrrolidin-2-onyl, pyrrolinyl, pyrrolyl,
quinolinyl, quinoxaloyl, tetrahydrofuryl, tetrahydroisoquinolyl,
tetrahydroquinolyl, tetrazolyl, thiadiazolyl, thiazolidinyl,
thiazolyl, thienyl, thiomorpholinyl, triazolyl, and the like.
Heterocyclics also include bridged bicyclic groups where a
monocyclic heterocyclic group is bridged by an alkylene group.
[0049] The term "hydroxyalkyl" as used herein refers to a hydroxy
radical attached to the parent molecular group through a small
alkyl group.
[0050] As will be understood by those of skill in the art by
reference to this disclosure, the small alkyl, small alkoxy,
cycloalkyl, haloalkyl, heterocyclyl, heterocyclylalkyl, aryl,
arylalkyl, heteroaryl, heteroarylalkyl, and hydroxyalkyl groups as
described herein may be unsubstituted, or substituted with, one or
more substitutents such as hydroxyl, halide, haloalkyl, small
alkyl, and small alkoxy.
[0051] The term "biological compound" as used herein refers to a
chemical compound that occurs in nature.
[0052] The term "biological extract" as used herein refers to an
extract from a biological sample, such as a plant extract, or other
extract from organic matter, containing chemical compounds that
occur in nature.
[0053] The term "reactive electrophilic group" as used herein
refers to an atom or group of atoms that has the ability to react
with a nucleophile.
[0054] The term "nitrogen-containing derivative" as used herein
represents those derivatives containing a nitrogen atom, where the
nitrogen atom is a substitution another atom, such as oxygen in the
parent compound.
[0055] The term "pharmaceutically-acceptable prodrugs" as used
herein represents those prodrugs of the compounds of the present
invention which are, within the scope of sound medical judgment,
suitable for use in contact with the tissues of humans and lower
animals with undue toxicity, irritation, allergic response, and the
like, commensurate with a reasonable benefit/risk ratio, and
effective for their intended use, as well as the zwitterionic
forms, where possible, of the compounds of the invention.
[0056] The term "prodrug" as used herein represents compounds which
are rapidly transformed in vivo to the parent compound of the above
formula, for example, by hydrolysis in blood.
[0057] The term "pharmaceutically acceptable salt" as used herein
refers to salts prepared from pharmaceutically acceptable non-toxic
bases including inorganic and organic bases. Examples of suitable
pharmaceutically acceptable salts for the compounds of the present
invention include metallic salts made from aluminum, calcium,
lithium, magnesium, potassium, sodium and zinc or organic salts
made from lysine, N,N'-dibenzylethylenediamine, chloroprocaine,
choline, diethanolamine, ethylenediamine,
meglumine(N-methylglucamine) and procaine.
[0058] Compounds of the present invention can exist as
stereoisomers wherein asymmetric or chiral centers are present. The
present invention contemplates various stereoisomers and mixtures
thereof. Stereoisomers include enantiomers and diastereomers, and
mixtures of enantiomers or diastereomers are designated. Individual
stereoisomers of compounds of the present invention can be prepared
synthetically from commercially available starting materials which
contain asymmetric or chiral centers or by preparation of racemic
mixtures followed by resolution well-known to those of ordinary
skill in the art.
[0059] Geometric isomers can also exist in the compounds of the
present invention. The present invention contemplates the various
geometric isomers and mixtures thereof resulting from the
arrangement of substituents around a carbon-carbon double bond or
arrangement of substituents around a carbocyclic ring.
[0060] The term "comprise" and variations of the term, such as
"comprising" and "comprises," are not intended to exclude other
additives, components, integers or steps.
[0061] According to one embodiment, compounds according to Formulas
I, II, and III, below are provided.
##STR00006##
and/or pharmaceutically acceptable salts and prodrugs thereof,
wherein,
[0062] R.sub.1 and R.sub.2 are each independently selected from the
group consisting of hydrogen, hydroxy, methoxy, halide, haloalkyl,
small alkyl, and small alkoxy;
[0063] R.sub.3, R.sub.4 and R.sub.5 are each independently selected
from the group consisting of hydrogen, small alkyl, cycloalkyl,
heterocyclyl, heterocyclylalkyl, aryl, arylalkyl, heteroaryl, and
heteroarylalkyl;
[0064] R.sub.6 and R.sub.7 are each independently selected from the
group consisting of hydrogen, small alkyl, hydroxyalkyl,
cycloalkyl, heterocyclyl, heterocyclylalkyl, aryl, arylalkyl,
heteroaryl, and heteroarylalkyl; or R.sub.6 and R.sub.7 along with
the nitrogen to which they are attached form a five or six membered
heterocyclic ring, comprising one or two heteroatoms selected from
the group consisting of oxygen, sulfur and nitrogen, wherein the
five or six membered heterocyclic ring is unsubstituted, or
substituted with a substituent selected from the group consisting
of hydroxy, hydroxyalkyl, halide, haloalkyl, small alkyl, small
alkoxy, and --CH.sub.2OR.sub.9;
[0065] R.sub.8 is selected from the group consisting of hydroxy,
small alkoxy, and --NR.sub.10R.sub.11;
[0066] R.sub.9 is selected from the group consisting of hydrogen,
small alkyl, cycloalkyl, heterocyclyl, heterocyclylalkyl, aryl,
arylalkyl, heteroaryl, and heteroarylalkyl;
[0067] R.sub.10 and R.sub.11 are each independently selected from
the group consisting of hydrogen, small alkyl, hydroxyalkyl,
cycloalkyl, heterocyclyl, heterocyclylalkyl, aryl, arylalkyl,
heteroaryl, and heteroarylalkyl; or R.sub.10 and R.sub.11 along
with the nitrogen to which they are attached form a five or six
membered heterocyclic ring, comprising one or two heteroatoms
selected from the group consisting of oxygen, sulfur and nitrogen,
wherein the five or six membered heterocyclic ring is
unsubstituted, or substituted with a substituent selected from the
group consisting of hydroxy, hydroxyalkyl, halide, haloalkyl, small
alkyl, small alkoxy, and --CH.sub.2OR.sub.9;
[0068] R.sub.12 is selected from the group consisting of hydrogen,
haloalkyl, and small alkyl;
[0069] R.sub.13 is selected from the group consisting of hydrogen,
and small alkyl;
[0070] R.sub.14 is selected from the group consisting of hydrogen,
and small alkyl;
[0071] R.sub.15 and R.sub.16 are each independently selected from
the group consisting of hydrogen, small alkyl, cycloalkyl,
heterocyclyl, heterocyclylalkyl, aryl, arylalkyl, heteroaryl, and
heteroarylalkyl; and
[0072] n, m, and p are each independently 0, 1, or 2.
[0073] According to one embodiment, compounds according to Formula
I comprise compounds of Formula I(a):
##STR00007##
and/or a pharmaceutically acceptable salts and prodrugs thereof,
wherein,
[0074] R.sub.6 and R.sub.7 along with the nitrogen to which they
are attached form a five or six membered heterocyclic ring of the
formula:
##STR00008##
[0075] wherein,
[0076] X is selected from the group consisting of --CH.sub.2,
--CHR.sub.17, --N.dbd., --O--, --S--, and --N--R.sub.17, wherein
each carbon atom of the five or six membered heterocyclic ring,
individually, is unsubstituted, or substituted with a substituent
selected from the group consisting of hydroxy, hydroxyalkyl,
halide, haloalkyl, small alkyl, small alkoxy, and
--CH.sub.2OR.sub.9; and
[0077] R.sub.17 is selected from the group consisting of hydrogen,
small alkyl, hydroxyalkyl, cycloalkyl, heterocyclyl,
heterocyclylalkyl, aryl, arylalkyl, heteroaryl, and
heteroarylalkyl.
[0078] More preferably, compounds according to Formula I comprise
compounds of Formula I(a)i, I(a)ii; and I(a)iii:
##STR00009##
[0079] and/or a pharmaceutically acceptable salts and prodrugs
thereof, wherein R.sub.18 is hydrogen, hydroxy, hydroxyalkyl,
halide, haloalkyl, small alkyl, small alkoxy, and
--CH.sub.2OR.sub.9.
[0080] Most preferably, compounds according to Formula I comprise
compounds of the formulas:
##STR00010##
[0081] and/or pharmaceutically acceptable salts and prodrugs
thereof.
[0082] According to another embodiment, compounds according to
Formula II comprise compounds of Formula IIa:
##STR00011##
[0083] and/or pharmaceutically acceptable salts and prodrugs
thereof.
[0084] According to another embodiment, compounds according to
Formula III comprise compounds of Formula III(a):
##STR00012##
[0085] and/or pharmaceutically acceptable salts and prodrugs
thereof, wherein,
[0086] R.sub.14, R.sub.15 and R.sub.16 are each independently small
alkyl;
[0087] n and m are each independently 0 or 1; and
[0088] p is 1 or 2.
[0089] More preferably, compounds according to Formula III comprise
compounds of Formulas III(a)i; III(a)ii; and III(a)iii:
##STR00013##
[0090] and/or pharmaceutically acceptable salts and prodrugs
thereof.
[0091] According to another preferred embodiment, compounds
according to Formulas I, II, and III, as shown by compound numbers
1-18 below are provided.
TABLE-US-00001 Compound Number Structure 1 ##STR00014## 2
##STR00015## 3 ##STR00016## 4 ##STR00017## 5 ##STR00018## 6
##STR00019## 7 ##STR00020## 8 ##STR00021## 9 ##STR00022## 10
##STR00023## 11 ##STR00024## 12 ##STR00025## 13 ##STR00026## 14
##STR00027## 15 ##STR00028## 16 ##STR00029## 17 ##STR00030## 18
##STR00031##
[0092] Other preferred compounds according to the present invention
are shown, for example, in FIG. 1, FIG. 2, and FIG. 3. FIG. 1
illustrates aromatic compounds of the invention for the treatment
of cognitive impairment and Alzheimer's disease. FIG. 2 illustrates
non-aromatic compounds of the invention for the treatment of
cognitive impairment and Alzheimer's disease; and FIG. 3 shows
isolated compounds of the invention having superior activity in a
beta-secretase assay for the treatment of cognitive impairment and
Alzheimer's disease.
[0093] According to another embodiment, a compound of any of the
above Formulas I, II, and/or III, including compound numbers 1-18,
and/or pharmaceutically acceptable salts and prodrugs thereof which
exhibit activity in a beta-secretase assay are provided.
[0094] According to another embodiment, a compound of any of the
above Formulas I, II, and/or III, including compound numbers 1-18,
and/or pharmaceutically acceptable salts and prodrugs thereof
formulated together with one or more pharmaceutically-acceptable
carriers is provided. The pharmaceutical compositions may be
specially formulated for oral administration in solid or liquid
form, for parenteral injection, or for vaginal or rectal
administration.
[0095] Solid dosage forms for oral administration include capsules,
tablets, pills, powders, and granules. In such solid dosage forms,
the active compound is mixed with at least one inert,
pharmaceutically-acceptable excipient or carrier including sodium
citrate or dicalcium phosphate, for example, and/or fillers or
extenders including starches, lactose, sucrose, glucose, mannitol,
and silicic acid, for example; and/or binders including
carboxymethylcellulose, alginates, gelatin, polyvinylpyrrolidone,
sucrose, and acacia, for example; and/or humectants such as
glycerol; and/or disintegrating agents including agar-agar, calcium
carbonate, potato starch, tapioca starch, alginic acid, certain
silicates, and sodium carbonate, for example; and/or solution
retarding agents such as paraffin; and/or absorption accelerators
such as quaternary ammonium compounds; and/or wetting agents
including cetyl alcohol and glycerol monostearate, for example;
and/or absorbents such as kaolin and bentonite clay, for example;
and/or lubricants such as talc, calcium stearate, magnesium
stearate, solid polyethylene glycols, sodium lauryl sulfate, for
example; and mixtures of the foregoing ingredients.
[0096] In the case of solid dosage forms, such as tablets, dragees,
capsules, pills, and granules, the dosage form may also comprise
buffering agents. Solid compositions of a similar type may also be
employed as fillers in soft and hard-filled gelatin capsules using
such excipients as lactose or milk sugar as well as high molecular
weight polyethylene glycols and the like. The solid dosage forms
may also be prepared with coatings and shells such as enteric
coatings and other coatings known in the pharmaceutical art. Dosage
forms may optionally contain opacifying agents and may also be of a
composition that they release the active ingredient(s) only, or
preferentially, in a certain part of the intestinal tract,
optionally, in a delayed manner. The active compounds can also be
in micro-encapsulated form, if appropriate, with one or more of the
above-mentioned excipients.
[0097] Liquid dosage forms for oral administration include
pharmaceutically-acceptable emulsions, solutions, suspensions,
syrups and elixirs. In addition to the active compounds, the liquid
dosage forms may contain inert diluents commonly used in the art
such as, for example, water or other solvents, solubilizing agents
and emulsifiers, and mixtures thereof, as will be understood by
those of skill in the art by reference to this disclosure. In
addition to inert diluents, the oral compositions can also include
adjuvants such as wetting agents, emulsifing and suspending agents,
sweetening, flavoring, and perfuming agents. Suspensions, in
addition to the active compounds, may contain suspending agents as,
for example, ethoxylated isostearyl alcohols, polyoxyethylene
sorbitol and sorbitan esters, microcrystalline cellulose, aluminum
metahydroxide, bentonite, agar-agar, and tragacanth, and mixtures
thereof.
[0098] Pharmaceutical compositions of this invention for parenteral
injection comprise pharmaceutically-acceptable sterile aqueous or
nonaqueous solutions, dispersions, suspensions or emulsions as well
as sterile powders for reconstitution into sterile injectable
solutions or dispersions just prior to use. These compositions may
also contain adjuvants such as preservative, wetting agents,
emulsifying agents, and dispersing agents. Prevention of the action
of microorganisms may be ensured by the inclusion of various
antibacterial and antifungal agents, for example, paraben,
chlorobutanol, phenol sorbic acid, and the like. It may also be
desirable to include isotonic agents such as sugars, sodium
chloride, and the like. Prolonged absorption an injectable
pharmaceutical form may be brought about by the inclusion of agents
which delay absorption such as aluminum monostearate and gelatin.
In some cases, it is desirable to slow the absorption of the drug
from subcutaneous or intramuscular injection. This may be
accomplished by the use of a liquid suspension of crystalline or
amorphous material with poor water solubility. Alternatively,
delayed absorption of a parenterally administered drug form is
accomplished by dissolving or suspending the drug in an oil
vehicle.
[0099] The compounds of the present invention may be used in the
form of pharmaceutically-acceptable salts derived from inorganic or
organic acids. By "pharmaceutically-acceptable salt" is meant those
salts which are, within the scope of sound medical judgment,
suitable for use in contact with the tissues of humans and lower
animals without undue toxicity, irritation, allergic response and
the like, and are commensurate with a reasonable benefit/risk
ratio, such as known to those of skill in the art. The salts may be
prepared in situ during the final isolation and purification of the
compounds of the invention or separately by reacting a free base
with a suitable acid.
[0100] Actual dosage levels of active ingredients in the
pharmaceutical compositions of this invention may be varied so as
to obtain an amount of the active compound or compounds that is
effective to achieve the desired therapeutic response for a
particular patient, compositions, and mode of administration. The
selected dosage level will depend upon the activity of the
particular compound, the route of administration, the severity of
the condition being treated, and the condition and prior medical
history of the patient being treated. However, it is within the
skill of the art to start doses of the compound at levels lower
than required for to achieve the desired therapeutic effect and to
gradually increase the dosage until the desired effect is achieved.
If desired, the effective daily dose may be divided into multiple
doses for purposes of administration, e.g. two to four separate
doses per day.
[0101] According to another embodiment, the invention comprises a
method of inhibiting, treating, or abatement of cognitive decline
and/or Alzheimer's disease in a mammal, the method comprising
administering a derivative of ginger oil to a mammal. Preferably,
the derivative is a nitrogen-containing derivative, meaning that
the derivative has one or more nitrogen containing groups such as
an amino group. According to the method, the symptom of cognitive
decline and/or Alzheimer's disease is one or more of memory loss,
confusion, impaired judgment, personality changes, disorientation,
and loss of language skills.
[0102] According to a preferred embodiment of the method, the
inhibiting, treating, or abatement of cognitive decline and/or
Alzheimer's disease comprises one or more of restoration of long
term potentiation; and/or inhibiting, treating, or abatement of one
or both of neurodegeneration and general amyloidosis. Also
according to a preferred embodiment of the method, inhibiting,
treating, or abatement of cognitive decline comprises inhibiting,
treating, or abatement of one or more of amyloid production,
amyloid assembly, amyloid aggregation, amyloid oligomer binding,
and amyloid deposition.
[0103] According to another preferred embodiment of the method, the
derivative of ginger oil is a compound in purified and isolated
form, and more preferably, the derivative of ginger oil is a
nitrogen-containing compound in purified and isolated form.
[0104] According to another embodiment, a method of inhibiting,
treating, or abatement of cognitive decline and/or Alzheimer's
disease in a patient by administering a compound according to the
invention to the patient is provided. Preferably, the compound is a
compound of any of the above Formulas I, II, and/or III, including
compound numbers 1-18, and/or pharmaceutically acceptable salts or
prodrugs thereof.
[0105] According to another embodiment, a method of preparing an
array of chemical compounds from a biological extract is provided.
Preferably, the method comprises preparing an array of
nitrogen-containing chemical compounds from a biological
extract.
[0106] The method of the invention, termed "chemical conditioning"
is generally applicable to all biological extracts, in particular,
natural plant extracts, common or medicinal. Chemical conditioning
is a method which produces novel unnatural drug-like compounds from
readily available natural materials. In general, the "chemical
conditioning" of natural extracts coupled with pre-fractionation of
the chemically conditioned extracts facilitates successful
biochemical screening of extracts by destroying reactive natural
compounds that generate false positive results in biochemical
assays. Chemical conditioning produces novel lead-like and
drug-like compounds and, the reductive amination protocol described
here can produce structurally diverse nitrogen-containing
nitrogen-containing products that are particularly lead-like and
drug-like.
[0107] The method of the present invention is exemplified in Scheme
I below. According to the method, first, a biological extract,
e.g., a plant extract is provided, the biological extract has one
or more biological compounds, each biological compound having one
or more reactive electrophilic groups. Next, the biological
compounds in the biological extract are reacted with an amine to
incorporate the amine into the biological compounds. Next, the
biological compounds having the incorporated amine are reacted with
a reducing agent to reduce the intermediate imine and enamine
compounds and form one or more nitrogen-containing chemical
compounds. Thus, the resultant nitrogen-containing chemical
compounds are derivatives of the biological compounds in the
biological extract. Preferably, the biological compounds in the
biological extract are compounds having ketones and aldehydes that
are reacted with various amines. This reaction is followed by
hydride reduction of the intermediate imines and enamines to
provide secondary and tertiary amines. The reaction of ketones and
aldehydes with amines, followed by reduction to form imines and
enamines is known in the art.
##STR00032##
[0108] The chemical conditioning method described herein employs a
biological extract, using many different reagents, to efficiently
produce an array of nitrogen-containing chemical compounds. The
ready commercial availability of many low molecular weight amines
for use as inputs in the reductive amination sequence enables the
development of many different and structurally diverse central
nervous system druglike mixtures from the same natural extract.
Suitable amines for use in the present method are selected from the
group consisting of primary amines, secondary amines, cyclic
amines, pyrollidine, and amino acids. Suitable reducing agents for
use in the present method are selected from the group of hydride
reducing agents including but not limited to sodium borohydride,
sodium triacetoxyborohydride, and lithium aluminum hydride.
[0109] The method may further comprise quenching the reaction a
quenching agent, wherein the quenching agent is selected from but
not limited to the group consisting of sodium bicarbonate, sodium
carbonate, sodium sulfate, sodium sulfate decahydrate. The method
may also further comprise isolating one or more of the
nitrogen-containing chemical compounds, in a purified or unpurified
form. The resultant nitrogen-containing chemical may then be
screened or tested for biological activity.
[0110] The process of chemical conditioning by reductive amination
described herein destroys reactive electrophiles in the natural
extract, including ketones, as in the gingerols, and converts them
to chemically stable compounds such as amines. The resulting
conditioned extracts contain both natural compounds and novel
unnatural nitrogen-containing amine products that are potential
drug candidates. In the case of the extracts of gingerol, the
nitrogen-containing amine products are potential central nervous
system drugs.
[0111] In a preferred embodiment of the invention, a plant extract
is obtained from ginger root. Natural ginger oil contains hundreds
of small molecules including the well-characterized aromatic
gingerol series of ketones shown in Table I below.
TABLE-US-00002 TABLE I Compound Structure Common Name ##STR00033##
Camphor ##STR00034## Bergamal ##STR00035## Prenylacetone
##STR00036## Citronelal
[0112] A representation of known volatile, non-aromatic components
of ginger oil that have been previously characterized is shown in
Table II below.
TABLE-US-00003 TABLE II Alkyl Chain Length (n) Compound Structure
Substituent (R) Common Name ##STR00037## n = 4 n = 6 n = 8
[6]-gingerol [8]-gingerol [10]-gingerol ##STR00038## n = 2 n = 4 n
= 5 n = 6 n = 8 n = 10 [5]-shogaol [6]-shogaol [7]-shogaol
[8]-shogaol [10]-shogaol [12]-shogaol ##STR00039## n = 4 n = 6 n =
8 [6]-gingerdiol [8]-gingerdiol [10]-gingerdiol ##STR00040## n = 4
n = 6 n = 8 [6]-dehydrogingerdione [8]-dehydrogingerdione
[10]-dehydrogingerdione ##STR00041## n = 4 n = 6 n = 8
[6]-gingerdione [8]-gingerdione [10]-gingerdione ##STR00042## n = 4
[6]-paradol ##STR00043## n = 4 n = 4 [6]-gingerdiol-3- monoacetate
[6]-gingerdiol-3,5- diacetate ##STR00044## n = 2 n = 4 n = 6
[0113] A specific example of the chemical conditioning process of
the invention is shown in Scheme II below. Scheme II shows the
two-step reductive amination chemical conditioning protocol
performed on ginger oil and ginger oleoresin in accordance with a
preferred embodiment of the method, wherein gingerol analogues
having a .beta.-hydroxycarbonyl function are converted to amino
alcohols. According to the method shown in Scheme II, first, an
extract of ginger containing one or more gingerols (A) and other
small molecules occurring in natural ginger extract is reacted with
an amine, (B). Then, the resultant compound (C) is then reduced,
with a reducing agent (D) to from the nitrogen-containing compounds
(E).
##STR00045##
[0114] In the next step of the method, one, or more than one
derivative is isolated from the extract. The conditioned extracts
are typically fractionated by flash chromatography and the
fractions are tested for enzyme inhibitor activity and receptor
binding affinity in Alzheimer's disease-relevant assays. Further
isolation and characterization of biologically active compounds may
follow.
[0115] New lead compounds generated by this chemical conditioning
method may then be prepared on preparative scale via multi-kilogram
SFE followed by the same chemical conditioning protocol described
herein.
[0116] In another embodiment, the present invention comprises an
isolated derivatives made in accordance with the foregoing
reductive amination process having the properties of a central
nervous system drug candidate. Desirable properties include
potential oral bioavailability, potential membrane permeability
and/or a low molecular weight. Preferably the molecular weight of
the derivative is less than about 550 Daltons, more preferably from
about 250 to about 450 Daltons. Most preferably, the derivatives of
ginger oil possesses beta-secretase inhibitory activity, and/or
inhibit amyloid production, amyloid assembly, amyloid aggregation,
amyloid oligomer binding, or amyloid deposition.
[0117] Preliminary data has demonstrated proof-of-principle in that
beta-secretase inhibitory activity has been observed in our
conditioned extracts where there was no inhibitory activity in
natural ginger oil. The isolation and characterization of
beta-secretase inhibitors as new lead compounds for the treatment
of cognitive decline and Alzheimer's disease has produced a new
structure-activity-relationship and has yielded the promising
beta-secretase inhibitors shown, for example in FIGS. 1-3. These
compounds are potential therapeutic agents for the treatment and
prevention of cognitive decline, amyloid production,
neurodegeneration, and Alzheimer's disease.
[0118] The invention may be appreciated in certain aspects with
reference to the following examples, offered by way of
illustration, not by way of limitation. Materials, reagents and the
like to which reference is made in the following examples are
obtainable from commercial sources, unless otherwise noted.
EXAMPLES
Materials And Methods
[0119] Ginger Oil
[0120] The light oil extract from ginger root was obtained by
supercritical CO.sub.2 extraction.
[0121] Ginger Oleoresin
[0122] The heavy remainder oil was obtained following extraction of
ginger root by supercritical CO.sub.2 extraction.
Conditioned Extraction of Ginger Oil
[0123] Reductive Amination of Ginger Oil (Method 1):
[0124] Ginger oil (10 g) was dissolved in toluene (250 mL) and
pyrrolidine (4.5 mL) was added. The mixture was maintained under an
atmosphere of nitrogen and heated at reflux with removal of water
by Dean-Stark distillation for 16 hr. At this time the Dean-Stark
trap was removed and the reaction mixture was cooled to 0.degree.
C. on an ice bath. A solution of sodium borohydride (5 g) in
methanol (50 mL) was added portion-wise over 30 minutes with
vigorous stirring. When the addition was complete the mixture was
heated to reflux for 16 hr. At this time the reaction mixture was
cooled to room temperature and poured into saturated aqueous sodium
bicarbonate (300 mL). The resulting mixture was concentrated by
rotary evaporation and the aqueous residue was partitioned between
water and chloroform. The chloroform layer was dried over anhydrous
sodium sulfate and then filtered and concentrated. The product was
then fractionated using silica gel column chromatography employing
a gradient from 100% chloroform to chloroform:methanol (4:1). Six
combined fractions from relatively non-polar to polar were
collected and concentrated. Each fraction was submitted for
biological testing. Beta-secretase enzyme assays were performed by
MDS Pharma, Bothell, Wash., according to Fukumoto et al.
(2004).
[0125] Reductive Amination of Ginger Oil (Method 2):
[0126] Ginger oil (10 g) was dissolved in toluene (250 mL) and
pyrrolidine (4.5 mL) was added.
[0127] The mixture was maintained under an atmosphere of nitrogen
and heated at reflux with removal of water by Dean-Stark
distillation for 16 hr. At this time the Dean-Stark trap was
removed and the reaction mixture was cooled to 0.degree. C. on an
ice bath. A solution of lithum aluminum hydride (58 mL, a 1 M
solution in tetrahydrofuran) was added portion-wise by syringe over
30 minutes with vigorous stirring. When the addition was complete
the mixture was heated to reflux for 16 hr. At this time the
reaction mixture was cooled to 0.degree. C. and the excess lithium
aluminum hydride was quenched by portion-wise addition of sodium
sulfate decahydrate. The resulting suspension was vacuum filtered
through a bed of sand and Celite. The collected solids were rinsed
with tetrahydrofuran (3.times.100 mL) and then once with a solution
of chloroform:methanol (4:1). The filtrate was concentrated by
rotary evaporation and the residue was partitioned between water
and chloroform. The chloroform layer was dried over anhydrous
sodium sulfate and then filtered and concentrated. The product was
then fractionated using silica gel column chromatography employing
a gradient from 100% chloroform to chloroform:methanol (4:1). Six
combined fractions from relatively non-polar to polar were
collected and concentrated. Each fraction was submitted for
biological testing. Beta-secretase enzyme assays were performed by
MDS Pharma, Bothell, Wash., according to Fukumoto et al.
(2004).
Conditioned Extraction of Ginger Oleoresin:
[0128] Reductive Amination of Ginger Oleoresin (Method 1):
[0129] Ginger oleoresin (10 g) was dissolved in toluene (250 mL)
and pyrrolidine (4.5 mL) was added. The mixture was maintained
under an atmosphere of nitrogen and heated at reflux with removal
of water by Dean-Stark distillation for 16 hr. At this time the
Dean-Stark trap was removed and the reaction mixture was cooled to
0.degree. C. on an ice bath. A solution of sodium borohydride (5 g)
in methanol (50 mL) was added portion-wise over 30 minutes with
vigorous stirring. When the addition was complete the mixture was
heated to reflux for 16 hr. At this time the reaction mixture was
cooled to room temperature and poured into saturated aqueous sodium
bicarbonate (300 mL). The resulting mixture was concentrated by
rotary evaporation and the aqueous residue was partitioned between
water and chloroform. The chloroform layer was dried over anhydrous
sodium sulfate and then filtered and concentrated. The product was
then fractionated using silica gel column chromatography employing
a gradient from 100% chloroform to chloroform:methanol (4:1). Six
combined fractions from relatively non-polar to polar were
collected and concentrated. Each fraction was submitted for
biological testing. Beta-secretase enzyme assays were performed by
MDS Pharma, Bothell, Wash., according to Fukumoto et al.
(2004).
[0130] Reductive Amination of Ginger Oleoresin (Method 2):
[0131] Ginger oleoresin (10 g) was dissolved in toluene (250 mL)
and pyrrolidine (4.5 mL) was added. The mixture was maintained
under an atmosphere of nitrogen and heated at reflux with removal
of water by Dean-Stark distillation for 16 hr. At this time the
Dean-Stark trap was removed and the reaction mixture was cooled to
0.degree. C. on an ice bath. A solution of lithum aluminum hydride
(58 mL, a 1 M solution in tetrahydrofuran) was added portion-wise
by syringe over 30 minutes with vigorous stirring. When the
addition was complete the mixture was heated to reflux for 16 hr.
At this time the reaction mixture was cooled to 0.degree. C. and
the excess lithium aluminum hydride was quenched by portion-wise
addition of sodium sulfate decahydrate. The resulting suspension
was vacuum filtered through a bed of sand and Celite. The collected
solids were rinsed with tetrahydrofuran (3.times.100 mL) and then
once with a solution of chloroform:methanol (4:1). The filtrate was
concentrated by rotary evaporation and the residue was partitioned
between water and chloroform. The chloroform layer was dried over
anhydrous sodium sulfate and then filtered and concentrated. The
product was then fractionated using silica gel column
chromatography employing a gradient from 100% chloroform to
chloroform:methanol (4:1). Each fraction was submitted for
biological testing. Beta-secretase enzyme assays were performed by
MDS Pharma, Bothell, Wash., according to Fukumoto et al.
(2004).
General Observations:
[0132] The biologically active fractions were generally found to be
the relatively polar fractions. These fractions had been newly
generated by the chemical conditioning process, in this particular
case, by reductive amination. The relatively polar active fraction
was not present in the natural ginger oil or in the natural ginger
oleoresin as analyzed by chromatography. Several conditioned
extractions of ginger oil and ginger oleoresin were performed using
a variety of amines to generate a structure-activity-relationship
between analogous compounds derived by reductive amination (Table
III). The examples shown are derived from the gingerol series of
compounds occurring in the natural starting materials. The
preferred beta-secretase inhibitors are shown in FIG. 6.
TABLE-US-00004 TABLE III Structure-activity-relationship of
aromatic inhibitors. Beta-secretase Example Structure MW activity 1
##STR00046## 349.5 +++ 2 ##STR00047## 377.5 +++ 3 ##STR00048##
379.5 ++ 4 ##STR00049## 407.6 ++ 5 ##STR00050## 353.5 + 6
##STR00051## 381.5 + 7 ##STR00052## 381.5 + 8 ##STR00053## 409.6 +
9 ##STR00054## 351.5 ++ 10 ##STR00055## 379.6 ++ 11 ##STR00056##
385.5 + 12 ##STR00057## 413.6 + 13 ##STR00058## 399.6 ++ 14
##STR00059## 427.6 ++
TABLE-US-00005 TABLE 2 Structure-activity-relationship of
non-aromatic inhibitors. Beta- Ex- secre- am- tase ple Structure MW
activity 15 ##STR00060## 207.4 +++ 16 ##STR00061## 181.3 +++ 17
##STR00062## 195.3 ++ 18 ##STR00063## 209.4 ++
Conclusion:
[0133] As described herein, compounds derived from ginger oil that
show activity in a beta-secretase inhibitor assay have been
developed. Methods for the treatment, inhibition, and abatement of
cognitive decline and Alzheimer's disease employing the compounds
of the present invention are also described herein. The compounds
of the present invention have been created and discovered using a
two-step reductive amination chemical conditioning procedure. This
two-step reductive amination chemical conditioning procedure, also
described herein, was performed on ginger root extract to arrive at
the compounds of the invention. However, this method should be
generally applicable to other biological, i.e., natural extracts to
generate novel drug-like compounds for screening for biological
activity, and new drug discovery.
[0134] Although the present invention has been described in
considerable detail with reference to certain preferred versions
thereof, other versions are possible. Therefore, the spirit and
scope of the invention should not be limited to the description of
the preferred versions described herein.
[0135] All features disclosed in the specification, including the
abstract and drawings, and all the steps in any method or process
disclosed, may be combined in any combination, except combinations
where at least some of such features and/or steps are mutually
exclusive. Each feature disclosed in the specification, including
abstract and drawings, can be replaced by alternative features
serving the same, equivalent or similar purpose, unless expressly
stated otherwise. Thus, unless expressly stated otherwise, each
feature disclosed is one example only of a generic series of
equivalent or similar features.
[0136] All references cited in this disclosure are incorporated
herein by reference in their entirety.
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