U.S. patent application number 10/034186 was filed with the patent office on 2003-07-10 for topical lightening compostitions and methods of use.
This patent application is currently assigned to AVON PRODUCTS, INC.. Invention is credited to Jones, Brian, Kyrou, Christos D., Mahalingam, Harish, Menon, Gopinathan K., Traudt, Michael.
Application Number | 20030129259 10/034186 |
Document ID | / |
Family ID | 21874835 |
Filed Date | 2003-07-10 |
United States Patent
Application |
20030129259 |
Kind Code |
A1 |
Mahalingam, Harish ; et
al. |
July 10, 2003 |
Topical lightening compostitions and methods of use
Abstract
There is provided a topical lightening composition having a
melanin synthesis-regulating agent and a vehicle. There is also
provided a topical lightening composition having an extract of
perilla leaf and a vehicle. There is also provided a topical
lightening composition having a lightening agent selected from the
group consisting of coconut water, palm water, palm nut milk, pecan
nut milk, almond nut milk, cashew nut milk, walnut nut milk,
concentrates of the foregoing, and any combinations thereof, along
with a vehicle. The compositions and methods of the invention are
effective to lighten skin, hair, lips, and/or nails.
Inventors: |
Mahalingam, Harish;
(Ledgewood, NJ) ; Jones, Brian; (Warwick, NY)
; Menon, Gopinathan K.; (Wayne, NJ) ; Kyrou,
Christos D.; (Goshen, NY) ; Traudt, Michael;
(Brookfield, CT) |
Correspondence
Address: |
Charles N.J. Ruggiero, Esq.
Ohlandt, Greeley, Ruggiero & Perle, L.L.P.
10th Floor
One Landmark Square
Stamford
CT
06901-2682
US
|
Assignee: |
AVON PRODUCTS, INC.
NEW YORK
NY
|
Family ID: |
21874835 |
Appl. No.: |
10/034186 |
Filed: |
December 28, 2001 |
Current U.S.
Class: |
424/727 ; 424/62;
424/725 |
Current CPC
Class: |
A61K 8/9794 20170801;
A61K 2800/70 20130101; A61Q 5/08 20130101; A61Q 19/02 20130101;
A61K 8/9722 20170801; A61P 17/14 20180101; A61K 8/9789
20170801 |
Class at
Publication: |
424/727 ;
424/725; 424/62 |
International
Class: |
A61K 035/78; A61K
007/135 |
Claims
What is claimed is
1. A composition, comprising: a) a topical lightening agent in an
amount effective to inhibit DOPAchrome tautomerase, DHICA
polymerase, or both; and b) a vehicle.
2. The composition of claim 1, wherein the topical lightening agent
has a melanin synthesis-regulating agent.
3. The composition of claim 2, wherein the melanin
synthesis-regulating agent is selected from the group consisting of
coconut water, palm water, concentrates of the foregoing, and any
combinations thereof.
4. The composition of claim 2, wherein the melanin
synthesis-regulating agent is a concentrate of coconut water.
5. The composition of claim 2, wherein the melanin
synthesis-regulating agent is selected from the group consisting of
coconut milk, palm nut milk, pecan nut milk, almond nut milk,
cashew nut milk, walnut nut milk, concentrates of the foregoing,
and any combinations thereof.
6. The composition of claim 2, wherein the topical lightening agent
further has a melanin uptake-inhibiting agent in an amount
effective to inhibit the transfer of melanin from melanocytes to
keratinocytes.
7. The composition of claim 6, wherein the melanin
uptake-inhibiting agent is an extract of perilla.
8. The composition of claim 6, wherein the melanin
uptake-inhibiting agent is an extract selected from the group
consisting of perilla leaf, perilla seed, perilla stem, and perilla
root.
9. The composition of claim 6, wherein the melanin
synthesis-regulating agent is a concentrate of coconut water and
the melanin uptake-inhibiting agent is a perilla leaf extract.
10. The composition of claim 1, wherein the topical lightening
agent is present in an amount about 0.001 to about 20 wt % based on
the total weight of the composition.
11. The composition of claim 1, wherein the topical lightening
agent is present in an amount about 0.01 to about 5 wt % based on
the total weight of the composition.
12. The composition of claim 1, wherein the topical lightening
agent is present in an amount about 0.1 to about 2.5 wt % based on
the total weight of the composition.
13. The composition of claim 1, wherein the composition is in a
product form selected from the group consisting of a cream, a
lotion, an ointment, a gel, a foam, a pomade, an aerosol spray, a
pump spray, a stick, a towelette, and a patch.
14. A method of lightening skin, hair, lips, and/or nails,
comprising: applying topically to the skin, scalp, hair, lips,
and/or nails the composition according to claim 1.
15. The method of claim 14, wherein the composition is topically
applied to treat a skin condition selected from the group
consisting of freckles, age spots, dark spots, hyperpigmentation,
post-inflammatory hyperpigmentation, discoloration, melasma,
yellowing, dark circles under the eyes, and any combinations
thereof.
16. A topical composition, comprising: a) an extract of perilla
leaf and b) a vehicle.
17. The composition of claim 16, wherein the perilla leaf extract
is present in an amount effective to inhibit the uptake of melanin
by keratinocytes in the skin.
18. The composition of claim 16, wherein the perilla leaf extract
is present in an amount about 0.001 to about 20 wt % based on the
total weight of the composition.
19. The composition of claim 16, wherein the perilla leaf extract
is present in an amount about 0.01 to about 5 wt % based on the
total weight of the composition.
20. The composition of claim 16, wherein the perilla leaf extract
is present in an amount about 0.1 to about 2.5 wt % based on the
total weight of the composition.
21. The composition according to claim 16, wherein the composition
is in a product form selected from the group consisting of a cream,
a lotion, an ointment, a gel, a foam, a pomade, an aerosol spray, a
pump spray, a stick, a towelette, and a patch.
22. A method of lightening skin, hair, lips, and/or nails,
comprising: applying topically to the skin, scalp, hair and/or
nails the composition according to claim 17.
23. The method of claim 22, wherein the composition is topically
applied to treat a skin condition selected from the group
consisting of freckles, age spots, dark spots, hyperpigmentation,
post-inflammatory pigmentation, discoloration, yellowing, melasma,
dark circles under the eyes, and any combinations thereof.
24. A composition, comprising: a) a topical lightening agent
selected from the group consisting of coconut water, palm water,
palm nut milk, pecan nut milk, almond nut milk, cashew nut milk,
walnut nut milk, concentrates of the foregoing, and any
combinations thereof; and c) a vehicle, wherein the topical
lightening agent is present in an amount effective to inhibit
DOPAchrome tautomerase, DHICA polymerase or both.
25. The composition of claim 24, wherein the topical lightening
agent is coconut water or a concentrate thereof.
26. The composition of claim 26, wherein the topical lightening
agent is present in an amount about 0.001 to about 20 wt % based on
the total weight of the composition.
27. The composition of claim 26, wherein the topical lightening
agent is present in an amount about 0.01 to about 5 wt % based on
the total weight of the composition.
28. The composition of claim 26, wherein the topical lightening
agent is present in an amount about 0.1 to about 2.5 wt % based on
the total weight of the composition.
29. A method of lightening skin, hair, lips, and/or nails
comprising: applying topically to the skin, scalp, lips, hair,
and/or nails the composition according to claim 24.
30. The method of claim 29, wherein the composition is topically
applied to treat a skin condition selected from the group
consisting of freckles, age spots, dark spots, hyperpigmentation,
post-inflammatory pigmentation, discoloration, yellowing, melasma,
dark circles under the eyes, and any combinations thereof.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to the lightening of the skin,
hair, nails and/or lips. The present invention further relates to
compositions and methods for lightening the skin, hair, nails
and/or lips.
[0003] 2. Description of the Prior Art
[0004] Consumers, particularly those in Asia, have sought to
lighten and reduce uneven pigmentation in the skin. Common skin
conditions treated include freckles, age spots, dark spots,
hyperpigmentation, discoloration, melasma, yellowing, and dark
circles under the eyes.
[0005] Numerous substances have been applied to the skin to lighten
the skin. Such substances include hydroquinone, kojic acid,
licorice and/or its derivatives, ascorbic acid/ascorbic acid
derivatives, arbutin, bearberry, Glycyrrhiza glabra and its
derivatives, Chlorella vulgaris extract, perilla extract, and
coconut fruit extract. Perilla extract is disclosed as a whitening
agent in U.S. Pat. Nos. 5,980,904 and Japanese Publications
07025742, 07187989, 10265322, 2001163759, and 2001181173. Coconut
fruit extract is disclosed as a whitening agent in Japanese Patent
No. 2896815 B2. An extract of spongy mass of coconut tissue is
employed in a tanning sunscreen composition in U.S. Pat. No.
5,756,099.
[0006] Skin and hair pigmentation is determined by the level of
melanin present in the epidermis and hair fiber, respectively.
Three different types of melanin are present in, for example, the
epidermis: DHI-melanin, DHICA-melanin and pheomelanin. The
different types of melanin vary in color or shade. DHI-melanin is
the darkest and is blackish in color. DHICA-melanin is brownish in
color. Pheomelanin is the lightest and is reddish in color.
[0007] Melanin is synthesized in specialized organelles called
melanosomes within pigment-producing cells (melanocytes).
Melanocytes respond to stimuli to regulate melanin synthesis.
[0008] Most conventional topical lightening agents act by
interfering with the action of tyrosinase, the enzyme that
catalyzes the conversion of the amino acid tyrosine to DOPAquinone.
Previously, it has not been known that hypopigmenting could be
achieved by inhibiting enzymes "downstream" from tyrosinase in the
melanin synthesis pathway. It has now been discovered that the use
of a melanin synthesis regulating agent that inhibits DOPAchrome
tautomerase and/or DHICA-polymerase results in a composition with
superior lightening, especially skin lightening.
[0009] It would be desirable to have a topical composition that
provides enhanced levels of lightening, bleaching, hypopigmenting,
whitening and/or depigmenting (hereinafter referred to individually
and collectively as "lightening" or "lighten"). It would be further
desirable to have a topical composition that contains lightening
agents that acted to interfere with the conversion of DOPAchrome to
DHI-melanin and DHICA-melanin. It would be yet further desirable to
have a topical composition that contains lightening agents that act
to inhibit or prevent the transfer (uptake) of melanin from the
melanocytes to the keratinocytes. It would still yet be further
desirable to have methods for lightening the skin, hair, nails
and/or lips employing the compositions of the present
invention.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide a
composition for lightening of the skin.
[0011] It is an object of the present invention to provide a
composition to alter/modify melanin synthesis in the skin.
[0012] It is an object of the present invention to provide a
composition to inhibit or prevent the uptake of melanin by
keratinocytes.
[0013] It is an object of the present invention to provide methods
for effecting the foregoing.
[0014] These and other objects and advantages of the present
invention are provided by a topical lightening composition
comprising a melanin synthesis-regulating agent, and a vehicle.
There is also a topical lightening composition comprising an
extract of perilla leaf and a vehicle. There is also a topical
lightening composition comprising a lightening agent selected from
the group consisting of coconut water, palm water, palm nut milk,
pecan nut milk, almond nut milk, cashew nut milk, walnut nut milk,
concentrates of the foregoing, and combinations of any of the
foregoing, and a vehicle. There are also methods for lightening the
skin, hair, lips, and/or nails comprising topically applying any
one of these compositions.
BRIEF DESCRIPTION OF THE DRAWING
[0015] FIG. 1 illustrates the results of the melanin uptake assay
in the Examples.
DETAILED DESCRIPTION OF THE INVENTION
[0016] It was found surprising and unexpected that there were
topical lightening compositions that provided enhanced levels of
performance heretofore not possible. It was found possible to
enhance lightening by inhibiting enzymes other than tyrosinase,
specifically DOPAchrome tautomerase (DCT) and/or
5,6-dihydroxyindole-2-carboxylic acid polymerase
(DHICA-polymerase). It was also found possible to enhance
lightening by inhibiting and/or preventing the uptake of melanin by
keratinocytes in, for example, the epidermis.
[0017] In its broadest aspects, the invention is not limited by any
particular characterization of the physiological and/or chemical
effects of topical lightening agents. However, the topical
lightening agents useful in the compositions and methods of the
present invention lighten the skin by regulating melanin production
and inhibiting the uptake of melanin in the skin, hair, lips,
and/or nails.
[0018] One embodiment of the present invention is the employment of
a melanin synthesis-regulating agent individually, or in
combination with a melanin uptake-inhibiting agent. When the
melanin synthesis-regulating agent is present in an amount
effective to inhibit DCT and/or DHICA polymerase, a superior
lightening composition can be attained. It was heretofore unknown
in the art that interference in this part of the melanin synthesis
pathway could bring about lightening of the skin, hair, lips,
and/or nails. A flow chart of the melanin synthesis pathway is as
follows: 1
[0019] Moreover, the use of an additional agent that functions to
inhibit the transfer (uptake) of melanin from the melanocytes to
the keratinocytes further enhances the lightening efficacy of the
present invention.
[0020] Examples of melanin synthesis-regulating agents include
coconut water, coconut milk, palm water, palm nut milk, pecan nut
milk, almond nut milk, cashew nut milk, walnut nut milk,
concentrates of each of the foregoing, or combinations of any of
the foregoing. Coconut water that has been concentrated, especially
by freeze-drying, is most preferred.
[0021] Examples of melanin uptake-inhibiting agents include
extracts or oils derived from all or parts of the perilla plant,
e.g. the leaf, seed, stem, and root. A preferred agent is extract
of the perilla leaf.
[0022] Another embodiment of the present invention is the use of
perilla leaf extract as a lightening agent in a topical lightening
composition, either individually or in combination with another
lightening agent. Perilla leaf extract provides an unexpected
enhancement of topical lightening efficacy compared to extracts,
concentrates, or oils of other parts of the perilla plant, i.e. the
seed, stem and root. In addition to enhanced efficacy, the perilla
leaf extract can provide topical lightening efficacy at a lower
amount compared to extracts of other parts of the perilla
plant.
[0023] Another embodiment of the present invention is the use of
any of the following as a topical lightening agent in a
composition: coconut water, palm water, palm nut milk, pecan nut
milk, almond nut milk, cashew nut milk, walnut nut milk,
concentrates of the foregoing, or combinations of any of the
foregoing. They can be used as the principal topical lightening
agent or in combination with other lightening agents. Coconut water
is preferred. A freeze-dried concentrate of coconut water is most
preferred. Coconut water or the concentrate thereof is believed to
provide superior lightening efficacy compared to extracts,
concentrates, or oils of other parts of the coconut and/or coconut
tree, i.e. the fruit, milk, shell, seed, leaf, and bark.
[0024] Topical lightening agents are present in the present
composition at a level sufficient to induce the desired effect of
lightening. The amount will vary depending upon the type of agent
and the nature and level of desired effect. The lightening agent
will typically be present from about 0.001 wt % to about 20 wt %,
more preferably from about 0.01 wt % to about 5 wt %, and most
preferably from about 0.1 wt % to about 2.5 wt %, based on the
total weight of the composition.
[0025] The compositions of the present invention preferably include
at least one, more preferably at least two, most preferably at
least three, of the following ingredients: aloe barbadensis or an
extract thereof, hydrolyzed soy protein, n-glucosamine,
gamma-aminobutyric acid, a competitive inhibitor of melanocyte
stimulating hormone (MSH) (e.g. hexapeptide-2), clintonia borealis
(bluebeard lily) or an extract thereof, milk proteins, hydrolyzed
milk proteins, sanguisorba officinalis (burnet), a glutathione
reductase inhbitor (e.g. wheat germ) or extracts thereof.
[0026] The compositions of the present invention can be used to
effectively lighten skin, hair, lips and nails be topically
applying the composition having an effective amount of the topical
lightening agent. To lighten the color or shade of hair, the
present compositions should preferably be rubbed onto/into the
scalp so that the composition can penetrate into the hair follicles
or root shafts and be absorbed into the hair during the melanin
production process.
[0027] The topical compositions of the present invention can be
applied to treat a variety of skin conditions, including freckles,
age spots, dark spots, hyperpigmentation, post-. inflammatory
hyperpigmentation, (e.g. post-acne hyperpigmentation),
discoloration, melasma, yellowing, and dark circles under the
eyes.
[0028] The present compositions may include any vehicle known in
the art. Suitable vehicles include, but are not limited to, water;
one or more vegetable oils; esters such as octyl palmitate,
isopropyl myristate and isopropyl palmitate; ethers such as
dicapryl ether and dimethyl isosorbide; alcohols such as ethanol
and isopropanol; fatty alcohols such as cetyl alcohol, stearyl
alcohol and behenyl alcohol; isoparaffins such as isooctane,
isododecane and isohexadecane; silicone oils such as dimethicones
and polysiloxanes; hydrocarbon oils such as mineral oil,
petrolatum, isoeicosane and polyisobutene; polyols such as
propylene glycol, glycerin, butylene glycol, pentylene glycol and
hexylene glycol; or combinations thereof.
[0029] Further optionally, the present compositions may include
additional skin whitening agents known in the art. Examples of
useful agents include the following: hydroquinone, kojic acid,
licorice and/or its derivatives, ascorbic acid/ascorbic acid
derivatives, arbutin, bearberry, Glycyrrhiza glabra and its
derivatives, and Chlorella vulgaris extract. Other whitening agents
are disclosed in U.S. Pat. No. 5,980,904, which is incorporated by
reference herein.
[0030] Further optionally, the present compositions may include one
or more of the following ingredients: anesthetics,
anti-allergenics, antifungals, antimicrobials, anti-inflammatories,
antiseptics, chelating agents, colorants, emollients, exfollients,
film formers, fragrances, humectants, insect repellents,
lubricants, moisturizers, pharmaceutical agents, preservatives,
skin protectants, skin penetration enhancers, stabilizers,
surfactants, thickeners, viscosity modifiers, or vitamins.
[0031] The compositions can be made into any suitable product form.
Such product forms include, but are not limited to, a cream,
lotion, ointment, gel, foam, pomade, aerosol spray, pump spray, a
stick, towelette, or patch.
EXAMPLES
[0032] The effect of coconut water (freeze-dried concentrate) on
the melanin synthesis pathway was demonstrated with various assays
using mouse melanoma cells from the S91 cell line (hereinafter
"cells"). The cells were cultured in 1:1 mixture of Ham F10+10%
horse serum and DMEM+10% fetal bovine serum. All cell experiments
were conducted in a humidified, 5% CO2 incubator at 37 degrees C.
Cells were treated with 0.02% and 0.05% w/v concentrations of
coconut water (freeze-dried concentrate) respectively for 24 hours.
Cell extracts were attained at 24 hours, and the following assays
were performed: DOPAchrome Tautomerase (Example 1) and DHICA
Polymerase (Example 2).
Example 1
DOPAchrome Tautomerase Assay (Coconut Water)
[0033] DOPAchrome Tautomerase (DCT) activity was assayed according
to the method disclosed in Chakraborty et al., 1998, Effect of
arbutin on melanogenic proteins in human melanocytes, Pigment Cell
Res. 11: 206-212. Specifically, ice-cold DOPA (0.5 mg per ml of 0.1
M sodium phosphate buffer, pH 6.8) was mixed with Ag.sub.2O (30 mg
Ag.sub.2O: 1 mg DOPA) for about 1 minute and filtered through a
0.22 .mu.m Millipore filter. DCT was assayed spectrophotometrically
by adding up to 0.1 ml cell extract to 0.5 ml of a solution of
freshly prepared DOPAchrome (.about.0.5 mg/ml). Reactions were
carried out at room temperature in plastic cuvettes, and the
disappearance of absorption at 475 nm was followed. Phenylthiourea
(1 mM) was added to the reaction mixture, because the presence of
tyrosinase in the cell extract can interfere with the assay. The
percentage conversion of DOPAchrome was calculated per mg of
protein extract and normalized against the control. It was
demonstrated that 0.02% wt./vol. coconut water (freeze-dried)
provided an average decrease in DOPAchrome conversion of 50%
(42/58) as compared to the control.
Example 2
DHICA Polymerase Assay (Coconut Water)
[0034] A DHICA polymerase assay was done according to the method
disclosed in Chakraborty et al., 1996, Polymerization of
5,6-dihydroxyindole-2-Carb- oxylic acid to melanin by the
pmel17/silver locus protein, Eur. J. Biochem. 236: 180-188.
Specifically, the cell extract (0.5 ml, 150-200 .mu.g protein) was
passed through a wheat germ agglutinin column (1 ml bed volume)
equilibrated with lysis buffer. The bound material was eluted with
0.5 ml 1M N-acetyl glucosamine, which contains crude DHICA
polymerization factor and other melanogenic proteins. A reaction
mixture of 0.5 ml containing either the enzyme preparation to be
measured (20 .mu.g protein from wheat germ agglutinin eluates) or
the appropriate buffer blank, DHICA (0.5 mM), and 100 mM sodium
phosphate buffer, pH 7.0. Phenylthiourea was also included to
inhibit endogenous tyrosinase activity in the preparation.
[0035] Spectrophotomeric reading of the absorbance of the reaction
mixture was taken at T=0 and T=4 hours time points at 400 nm.
DHICA-melanin, but not DHICA itself, has been shown to absorb light
at these wavelengths (Orlow et al., 1992, Synthesis and
characterization of melanins from dihydroxyindole-2-carboxylic acid
and dihydroxyndole, Pigment Cell Res. 5: 113-121). An increase in
absorbance over that seen in blank tubes was defined as specific
DHICA polymerization factor activity. It was demonstrated that
0.02% wt./vol. coconut water (freeze-dried) provided an average of
52.5% (55%/50%) decrease in DOPAchrome conversion as compared to
the control. At 0.05% wt./vol. coconut water (freeze-dried)
provided an average decrease of 75% (74/76) in DOPAchrome
conversion as compared to the control.
Example 3
Melanosome Uptake Assay (Perilla Leaf Extract)
[0036] Melanosome Isolation
[0037] Confluent cultures of B16 melanocytes produce moderate
levels of melanosomes. However, to induce elevated melanosome
production in this cell line, semi-confluent (60%) cultures of B16
cells were treated for approximately 36 hours with normal growth
medium supplemented with 10 mM ammonium chloride (final conc.). The
medium was then aspirated and the hypermelanotic cells were washed
(2.times.2 ml) with distilled water to provide a hypotonic stress
to the cells. An aliquot (2 ml) of a hypotonic lysis solution
(0.02% NP-40 in water) was added to each plate and the plates were
incubated for approximately 5 min at room temperature. Following
verification of cell lysis using light microscopy, the cellular
material from three (3) culture plates were pooled in a 15 ml
conical tube and centrifuged at approximately (200.times.g) for 5
minutes to remove cellular debris. The resulting supernatant
containing melanosomes was transferred to a clean 15 ml conical
tube and centrifuged (850.times.g) for 20 minutes. The resulting
pellet containing the isolated melanosomes were resuspended in 1 ml
of Phosphate Buffered Saline (PBS) and stored at 4.degree. C. until
used.
[0038] Treatment of Keratinocytes with Melanosomes
[0039] The normal human epidermal keratinocytes (NHEKs) (available
from Clonetics, Inc.) were plated in the wells of 24-well plates at
a density of 200,000 cells/well. Approximately 24 hours later, the
growth medium was replaced with 1 ml of the appropriate growth
medium (i.e., DMEM/KGM-2) containing the melanosome preparation
with or without additional treatment conditions. The cells were
treated with different concentations of perilla leaf extract
(powder form or aqueous form). The cells were then returned to the
incubator for approximately 1.5 hours. For these studies, each well
of keratinocytes was treated with the amount of melanosomes
isolated from a single plate of B16 cells.
[0040] In some experiments, the 24 well plates of treated
keratinocytes were centrifuged for 15 minutes at 1,000 rpm to
facilitate the deposition of the melanosomes onto the surface
membranes of the keratinocytes. The plates were then returned to
the incubator for 1.25 hours.
[0041] Analysis of Melanosome Uptake
[0042] For analysis, the cells in each well of keratinocytes were
rinsed (3.times.1 ml) with PBS, removed from the plate using
trypsin/EDTA, washed with PBS. To analyze the uptake of melanosomes
by the keratinocytes, the internalized melanin was extracted from
the cells according to a modified method of Bessou-Touya, S., et
al. (Chimeric human epidermal reconstructs to study the role of
melanocytes and keratinocytes in pigmentation and photoprotection.
J. Invest. Dermatol., 111:1103-1108, 1998) and quantified
spectrophotometrically by determining the melanin-specific
absorbance at 405 nm.
[0043] Results
[0044] Melanocytes synthesize melanin and deposits onto
melanosomes. Visual manifestation of skin color is due to presence
of melanin/melanosomes in keratinocytes. Melanosomes are taken up
by keratinocytes and the rate of uptake, retention and processing
of melanosomes in the keratinocytes is a key determinant of skin
color. Thus, the internalized melanin value reflects the amount of
melanin/melanosome uptake and retention by the keratinocytes. Thus,
lower internalized melanin values, particularly internalized
melanin values that are less than the control with melanin,
indicate that melanin uptake by the keratinocytes has been
inhibited. As illustrated in FIG. 1, internalized melanin values
for perilla leaf extract were lower than internalized melanin
values of the control with melanin.
[0045] It should be understood that the foregoing description is
only illustrative of the present invention. Various alternatives
and modifications can be devised by those skilled in the art
without departing from the invention. Accordingly, the present
invention is intended to embrace all such alternatives,
modifications and variances which fall within the scope of the
appended claims.
* * * * *