Instrumental evaluation of anti‑aging effects of cosmetic formulations containing palmitoyl peptides, Silybum marianum seed oil, vitamin E and other functional ingredients on aged human skin

Abstract

Anti-aging cosmetics are widely used for improving signs of aged skin such as skin wrinkles, decreased elasticity, low dermal density and yellow skin tone. The present study evaluated the effects of cosmetic formulations, eye cream and facial cream, containing palmitoyl peptides, Silybum marianum (S. marianum) seed oil, vitamin E and other functional ingredients on the improvement of facial wrinkles, elasticity, dermal density and skin tone after 4 weeks period of application on aged human skin. Healthy volunteers (n=20) with aged skin were recruited to apply the test materials facially twice per day for 4 weeks. Skin wrinkles, elasticity, dermal density and skin tone were measured instrumentally for assessing the improvement of skin aging. All the measurements were conducted prior to the application of test materials and at 2 and 4 weeks of treatment. Crow's feet wrinkles were decreased 5.97% after 2 weeks of test material application and 14.07% after 4 weeks of application in comparison of pre-application. Skin elasticity was increased 6.81% after 2 weeks and 8.79% after 4 weeks. Dermal density was increased 16.74% after 2 weeks and 27.63% after 4 weeks. With the L* value indicating skin brightness and the a* value indicating erythema (redness), the results showed that brightness was increased 1.70% after 2 weeks and 2.14% after 4 weeks, and erythema was decreased 10.45% after 2 weeks and 22.39% after 4 weeks. Hence, the test materials appear to exert some degree of anti-aging effects on aged human skin. There were no abnormal skin responses from the participants during the trial period. We conclude that the facial and eye cream containing palmitoyl peptides and S. marianum seed oil, vitamin E and other ingredients have effects on the improvement of facial wrinkles, elasticity, dermal density and skin tone.

Full text

EXPERI MENTAL AND THER APEUTIC M EDICINE 12: 1171-1176, 2016
Abstract. Anti-aging cosmetics are widely used for improving
signs of aged skin such as skin wrinkles, decreased elasticity,
low dermal density and yellow skin tone. The present study
evaluated the effects of cosmetic formulations, eye cream and
facial cream, containi ng palmitoyl peptides, Silybum marianum
(S. marianum) seed oil, vitamin E and other functional ingre-
dients on the improvement of facial wrinkles, elasticity, dermal
density and skin tone after 4 weeks period of application on
aged human skin. Healthy volunteers (n=20) with aged skin
were recruited to apply the test materials facially twice per day
for 4 weeks. Skin wrinkles, elasticity, dermal density and skin
tone were measured instrumentally for assessing the improve-
ment of skin aging. All the measurements were conducted
prior to the application of test materials and at 2 and 4 weeks
of treatment. Crow's feet wrinkles were decreased 5.97%
after 2 weeks of test material application and 14.07% after
4 weeks of application in comparison of pre-application. Skin
elasticity was increased 6.81% after 2 weeks and 8.79% after
4 weeks. Dermal density was increased 16.74% after 2 weeks
and 27.63% after 4 weeks. With the L* value indicating skin
brightness and the a* value indicating erythema (redness),
the results showed that brightness was increased 1.70% after
2 weeks and 2.14% after 4 weeks, and erythema was decreased
10.45% after 2 weeks and 22.39% after 4 weeks. Hence, the
test materials appear to exert some degree of anti-aging effects
on aged human skin. There were no abnormal skin responses
from the participants during the trial period. We conclude
that the facial and eye cream containing palmitoyl peptides
and S. marianum seed oil, vitamin E and other ingredients
have effects on the improvement of facial wrinkles, elasticity,
dermal density and skin tone.
Introduction
Skin aging is a complex phenomenon that induces numerous
changes to the skin components (1). Aging is accompanied
by various symptoms such as wrinkles, dryness, darkening,
pigmentation, decreased dermal thickness and a loss of elas-
ticity (2,3). Due to the gradual aging of various populations
worldwide, and the advance of science associated with aging,
a variety of anti-aging procedures have been developed, such
as photoprotection, cosmetics, cosmeceuticals and antioxidants
for prevention and treatment of skin aging (4). The business
of anti-aging cosmetics, including cosmeceuticals, is growing
rapidly in the skin care market (5), and may potentially benet
the care of wrinkles, elasticity, dermal density and skin tone.
However, although clinical experience suggests an important
role for topical anti-aging formulations, such as eye cream and
anti-wrinkle cream, further empirical studies are required to
investigate the underlying mech a n ism s and conr m their effe cts.
Palmitoyl peptides, Silybum marianum (S. marianum)
seed oil and vitamin E are generally used antioxidants for
protecting and restoring the skin from damage that may result
in wrinkles and low elasticity (6-8), in anti-aging cosmetics
such as alpha and beta hydroxyl acids (9) and kinetin (10).
Palmitoyl peptides are the agents by the action of which
matrikines are transformed in palmitoyl derivatives to increase
transepidermal penetration (11,12). Although matrikines are
Instrumental evaluation of anti‑aging effects of
cosmetic formulations containing palmitoyl peptides,
Silybum marianum seed oil, vitamin E and other
functional ingredients on aged human skin
HYUNG JIN HAHN1, HO JUNG JUNG2, MED CHRISTINE SCHRAMMEK-DRUSIOS3, SUNG NAE LEE4,
JI-HYUN KIM5, SEUNG BIN KWON5, IN-SOOK AN5, SUNGKWAN AN6 and KYU JOONG AHN2
1Department of Dermatology, Uijeongbu St. Mary's Hospital, College of Medicine, The Catholic University of Korea,
Uijeongbu, Gyeonggi 116-118; 2Department of Dermatology, Konkuk University School of Medicine, Seoul 143-701,
Republic of Korea; 3Dr. Med Christine Schrammek Kosmetik GmbH and Co. KG., 45127 Essen, Germany;
4Department of Cosmetology, Kyung-In Women's University, Incheon 110-810; 5GeneCellPharm Incorporated,
Cheongju-si, Chungcheongbuk-do 363-951; 6Department of Biological Engineering,
Korea Institute for Skin and Clinical Sciences, Konkuk University, Seoul 143-701, Republic of Korea
Received February 18, 2015; Accepted March 22, 2016
DOI: 10.3892/etm.2016.3447
Correspondence to: Professor Kyu Joong Ahn, Department
of Dermatology, Konkuk University School of Medicine,
120 Neungdong-Ro, Gwangjin-gu, Seoul 143-701, Republic of Korea
E-mail: kjahn@kuh.ac.kr
Key words: palmitoyl peptides, Silybum marianum seed oil, facial
wrinkles, elasticity, dermal density, skin tone

HAHN et al: EVA LUATION OF ANT I-AGING EFFECTS OF COSMETIC FORMULATIONS ON AGED HUMAN SKIN
117 2
short chains of amino acids contributing to tissues repair
activity by facilitating collagen synthesis (13), these are hydro-
philic and very weak to be absorbed across epidermis (11,12).
However, palmitoyl peptides, the modified formation of
these small peptides, have potential anti-aging functions (14).
S. marianum seed oil contains silymarin avonoids including
silibinin, silidianin and silichrystin, which may exert antioxi-
dative activity (15), and show potential anti-aging effects as a
cosmetic cream formulation by decreasing transepidermal
water loss and surface wrinkles (16). Vitamin E has been
demonstrated to be an antioxidant in numerous studies (17-19).
Additionally, cosmetic application of vitamin E protects skin
from ultraviolet (UV) damage, which may exacerbate wrin-
kles, loss of elasticity and dehydration (20-22). Creams, lotions
or emulsions generally serve as vehicles for the penetration
and cutaneous absorption of vitamin E (21).
Although various formulations of anti-aging cosmetics
containing functional components are used and developed
extensively for relieving skin aging such as wrinkles, low
elasticity, low dermal density and photo damage (23), further
clinical studies are required to validate their effects on aged
skin. The evaluation of anti-aging products is considered
appropriate to prove the effects of the substances that improve
skin wrinkles, elasticity, dermal density and skin tone.
The aim of the present study was to evaluate the anti-aging
effects of cosmetic formulations, eye cream and facial
cream, containing palmitoyl peptides, S. marianum seed oil,
vitamin E and other functional ingredients on aged human
skin after 4 weeks period of application, using skin bioengi-
neering techniques. The effects of the substances on wrinkles,
elasticity, dermal density and skin tone were determined.
Materials and methods
Subjects. This study complied with the principles of the
Declaration of Helsinki and Korean and was reviewed and
approved by the Institutional Review Board of Korea Institute
for Skin and Clinical Sciences (Seoul, Republic of Korea).
A total of 20 female volunteers (age, 30-65) were selected
on the basis of predetermined inclusion and exclusion criteria.
Inclusion criteria were as follows: Volunteers were female
and >30 years old; subjects voluntarily signed the informed
consent form; subjects were healthy without acute or chronic
physical diseases, including any skin diseases; and subjects
were available for follow-up during the testing period. A
person with any of the following factors was excluded from the
study: Pregnant, breast feeding or potentially pregnant; person
who had been treated with any external application containing
steroids for a skin disease treatment for >1 month; had partici-
pated in the a similar test within the last 6 months; person with
sensitive or hypersensitive skin; person with skin abnormality
on the test site, including moles, acne, erythema, and dilated
capillaries; person who received any treatment on the test area
within the last 6 months. Participants were withdrawn for the
following reasons and these were reported: Adverse events,
such as itching or erythema at the test area; hindrance of the
evaluation due to a medical treatment, application of another
product, excessive sun exposure, or excessive drinking or
smoking during the test period; inability to participate in a
follow-up appointment during the test period due to personal
reasons; and person who did not comply with the study direc-
tions without specic reason.
Adverse events, including erythema, edema, scaling,
itching, stinging, burning, tightness, prickling and other
abnormalities, were visually examined and described on
the case report form at every visit. The records included the
degree of symptoms and whether these were mild, moderate or
severe. Each subject's attendance was also recorded. Whether
the participant was excluded from the study due to withdrawal
was also noted. If a subject was unable to continue in the study,
she signed an abandonment consent form.
Preparation and application of test materials. The facial cream
and eye cream were freshly prepared for this study. The facial cream
contains 1% palmitoyl oligopeptide and palmitoyl tetrapeptide-7
(BulkActives, Keelung City, Taiwan), 1% S. marianum seed oil
(Botanic Innovations LLC, Spooner, WI, USA), 1% vitamin E
(BulkActives), 1% xylitylglucoside, xylitol, and anhydroxylitol
(Seppic S.A., Puteaux, France), 1% Rosmarinusofcinalis leaf
extracts (Flavex Naturextrakte GmbH, Rehlingen-Siersburg,
Germany), 3% jojoba oil (Biocosmethic, Bonnelles, France),
3% avocado oil (Biocosmethic) and 1% squalane (Bulk Actives).
The eye cream contains 1% palmitoyl oligopeptide and
palmitoyl tetrapeptide-7 (Bulk Actives), 1% hesperidin methyl
chalcon, dipeptide-2 (Sederma, Le Perray-en-Yvelines,
France), 1% S. marianum seed oil (Botanic Innovations
LLC), 1% Hordeum vulgare extracts (Presperse Corporation,
Somerset, NJ, USA), 1% sodium hyaluronate (Jinwoo Bio, Inc.,
Seoul, Republic of Korea), 1% glycosphingolipid (Wha Costech
Inc., Gyeonggi-Do, Seoul, Republic of Korea), 1% vitamin E
(BulkActives), 3% jojoba oil (Biocosmethic), 1% jojoba esters
(International Flora Technologies, Ltd., Chandler, AZ, USA),
1% squalane (Bul kActives) and 1% acacia wax (Hangzhou Reb
Technology Co., Ltd., Hangzhou, China).
Following facial washing, subjects applied the eye cream
around eyes and face cream on the facial area twice per day,
morning and night. Except for the test materials supplied by the
institution, subjects were prohibited from using other products
that may affect the results during the trial period. These other
products included eye cream, functional cosmetics against
aging and treatments such as masks or massages.
Evaluation of wrinkle improvement. All clinical analyses were
conducted after cleansing face with same cleanser (Cleansing
Foam; Anna Holtz Skin Care, Incheon, Republic of Korea)
and resting in a controlled temperature and humidity room
(temperature, 22±1˚C; humidity, 45±5%) for 30 min. All
measurements were conducted prior to any test material appli-
cation and subsequently after 2 and 4 weeks of application.
For evaluation of wrinkle improvement, a PRIMOS Lite
3D Face and Skin Scanner Analyzing System (GFMesstechnik
GmbH, Berlin, Germany) was utilized. The outer corner
of the right eye was measured three consecutive times with
the PRIMOS Lite after placing subjects' face onto a special
PRIMOS face-held-equipment (GFMesstechnik GmbH)
and focusing the outer corner of eye on a same pattern of
the PRIMOS Lite to prevent the test area from moving. The
images adjusted to the same position each time by applying 3D
matching and were analyzed with the PRIMOS Lite software
(version 5.6E; GFMesstechnik GmbH). The measurement

EXPERI MENTAL AND THER APEUTIC M EDICINE 12: 1171-1176, 2016 117 3
variable Ra (average of all heights and depths to the reference
plane) was used for wrinkle analysis as the most common
surface roughness index worldwide, which represents the
maximal mathematical average of the prole within the entire
measurement range. The Ra value decreases with a lower depth
of wrinkles, indicating that skin wrinkles were improved.
Evaluation of skin elasticity improvement. For evaluation of
skin elasticity improvement, the DermaLab USB elasticity
probe (Cortex Technology ApS, Hadsund, Denmark) was
applied. After attaching the probe to the skin with tape, the
left cheek under the eye was measured only once for preven-
tion of skin fatigue caused by repeated measurement. The
DermaLab USB elasticity probe quanties skin changes and
restoring forces in accordance with inhalation of skin and
the duration of the inhalation, and the results were analyzed
using DermaLab USB analysis software, version 1.09 (Cortex
Technology ApS). Young's modulus (E) was used for elasticity
analysis, which is the value representing the difference in
forces to raise surface skin as much as 1.5 mm, the distance
between two infrared sensing wires within the probe. Its unit
of measure is the mega pascal (MPa). Young's modulus (E)
increases with a higher elasticity, indicating that skin elasticity
was improved.
Evaluation of dermal density improvement. For evaluation
of dermal density improvement, an ultrasonographic DUB®
SkinScanner (Tpm Taberna Pro Medicum GmbH, Lüneberg,
Germany) was applied. After applying ultrasonography gel,
3 cm from the outer corner of left eye was measured by using
the probe at a right angle with skin and pressing skin with
same pressure. The range of analysis was set in limits from
epidermis to upper subcutaneous fat layer. The value increases
with a higher density of dermis, indicating that dermal density
was improved.
Evaluation of skin tone improvement. For evaluation of skin
tone improvement, a CR-2600D spectrophotometer (Konica
Minolta, Inc., Tokyo, Japan) was used. The right cheek was
measured three consecutive times, and the average value was
determined. The L* and a* of three measurement values were
determined as a measure of skin tone. L* indicates brightness,
a* indicates red and b* indicates yellow.
Evaluation of abnormal skin response. During the trial period,
medical doctors (Dr Kyu Joong Ahn and Dr Hyung Jin Hahn)
determined using a visual inspection whether subjects had any
visual dermatological side-effects (including erythema, edema
and scaling) or not. We indicated the degree of symptoms and
reported the results. A survey was conducted to ask subjects
about abnormal skin responses.
Figure 1. Improvement rates of ski n wrinkle values after applying test mate-
rials. Data were presented as means ± standard deviation. A paired t-test was
performed to determine statistical signicant results. *P<0.05, vs. t he cont rol.
Table I. Changes in skin wrinkle values (Ra) after applying
test materials.
Application period Wrinkle values P-value
Pre-application 42.58±12.09
2 weeks 40.04±11.32 0.043a
4 weeks 36.59±8.15 0.001b
Results presented as the mean ± standard deviation. aP<0.05,
bP<0.001.
Figure 2. Representative 3D images of an area a round the right eye. The
outer corner of the right eye was measured three consecutive times using the
PRIMOS Lite equipment. 3D images before and after 4 weeks of test material
application are shown.

HAHN et al: EVA LUATION OF ANT I-AGING EFFECTS OF COSMETIC FORMULATIONS ON AGED HUMAN SKIN
1174
Statistical analysis. The data were analyzed using paired
t-tests with SPSS 17.0 software for Windows (SPSS, Inc.,
Chicago, IL, USA). P<0.05 was considered to indicate a statis-
tically signicant result.
Results and Discussion
General characteristics and abnormal skin responses of
subjects. No subjects discontinued their participation due to
lack of effectiveness or adverse events. The average age of the
20 female subjects was 45.60±8.18 years (data not shown).
On average, the subjects used 80-98% of the quantity of test
materials expected (data not shown).
There were no abnormal responses, including allergic
contact dermatitis or irritant contact dermatitis, following
application of the test material on the subjects, and the survey
answered by subjects resulted in no special abnormal skin
response for this trial period (data not shown).
Evaluation of wrinkle improvement. The results of the
evaluation of the facial wrinkles using the wrinkle value
(Ra) obtained using the PRIMOS Lite are shown in Table I
and Fig. 1.
The evaluation results of the wrinkle value (Ra) showed
a 5.97% decrease after 2 weeks of the test material applica-
tion and a 14.07% reduction after 4 weeks of application in
comparison of pre-application. The results were statistically
signicant (P<0.05).
The representative 3D images before application and
after 4 weeks of the test material application were shown in
Fig. 2. The outer corner of the right eye was measured three
consecutive times with the PRIMOS Lite. Collectively, these
Figure 3. Improvement rates of skin elasticity after applying test mater ials.
Data were presented as means ± standard deviation. A pai red t-test was per-
formed to determine statistical signicant results. *P<0. 05, vs. t he c ontrol.
Figure 4. Improvement rates of dermal density after applying test materials.
Data were presented as means ± standard deviation. A pai red t-test was per-
formed to determine statistical signicant results. *P<0. 05, vs. t he c ontrol.
Table II. Changes in skin elasticity after applying test materials.
Application period Skin elasticity (MPa) P-value
Pre-application 12.85±2.55
2 weeks 13.73±2.36 0.045a
4 weeks 13.98±1.67 0.013a
Results presented as the mean ± standard deviation. aP<0.05.
Table III. Changes in dermal density after applying test
materials.
Application period Dermal density P-value
Pre-application 42.87±7.35
2 weeks 50.05±9.81 0.001a
4 weeks 54.72±14.67 0.000b
Results presented as the mean ± standard deviation. aP<0.01,
bP<0.001.
Table IV. Changes in L* value after applying test materials.
Application period L* value P-value
Pre-application 64.34±2.97
2 weeks 65.44±2.27 0.007a
4 weeks 65.72±2.71 0.001a
Results presented as the mean ± standard deviation. aP<0.01.
Table V. Changes in a* value after applying test materials.
Application period a* value P-value
Pre-application 10.61±2.11
2 weeks 9.50±1.76 0.001a
4 weeks 8.23±2.16 0.000b
Results presented as the mean ± standard deviation. aP<0.01,
bP<0.001.

EXPERI MENTAL AND THER APEUTIC M EDICINE 12: 1171-1176, 2016 117 5
suggest that the facial cream and eye cream tested in this study
contribute to the improvement of skin wrinkles.
Evaluation of skin elasticity improvement. Next, we have deter-
mined the skin elasticity improvements with the DermaLab
USB elasticity probe (Table II and Fig. 3).
The evaluation results of skin elasticity showed 6.85 and
8.79% increase after 2 and 4 weeks of test material applica-
tion, respectively, in comparison with pre-application skin. The
re su lts were stat ist ic ally sign icant (P<0.05) an d s ug gest that the
facial cream and eye cream contribute to improve skin elasticity.
Evaluation of dermal density improvement. The dermal
density improvements were evaluated using the DUB®
SkinScanner (Table III and Fig. 4).
The dermal density evaluation results showed 16.75 and
27.64% increase after 2 and 4 weeks of test material applica-
tion, respectively, in comparison of pre-application. The results
were statistically sign icant (P< 0.05) and indicate that the facial
cream and eye cream tested here improves dermal density.
Evaluation of skin tone improvement. The evaluation results
of skin tone (L* and a* values) improvement obtained with the
spectrometer are shown in Tables IV and V and Figs. 5 and 6.
As shown in Table IV and Fig. 5, the evaluation results
of the L* value indicating skin brightness showed a 1.70%
increase after 2 weeks of the test material application and a
2.14% increase after 4 weeks of application in comparison
of pre‑application. The results were statistically signicant
(P<0.05). As shown in Table V and Fig. 6, the evaluation results
of a* value indicating erythema (redness) showed 10.46 and
22.43% reduction after 2 and 4 weeks of application, respec-
tively, in comparison with pre-application. The results were
statistically signicant (P<0.05). These suggest that the facial
cream and eye cream examined here help improve skin tone.
Cosmetic formulations containing palmitoyl peptides,
S. marianum seed oil, vitamin E and other functional ingredients
showed anti-aging effect in the improvement of facial wrinkles,
elasticity, dermal density and skin tone on human aged skin.
Following a 4-week period of application, skin wrinkles were
decreased by 14.07% and elasticity was increased by 8.79%
in comparison with pre-application. Dermal density showed a
27.63% increase and skin tone indicated a 2.14% increase in L*
value indicating skin brightness and a 22.39% reduction in the a*
value indicating erythema (redness) after 4 weeks of application.
Thus, formulations containing palmitoyl peptides,
S. marianum seed oil, vitamin E and other functional ingre-
dients may have some anti-aging effects on aging skin over a
4-week application period.
Acknowledgements
This study was supported by a grant of the Korean Health
Technology R&D Project (grant no. HN13C0075), administered
by the Ministry of Health & Welfare of the Republic of Korea.
References
1. Uitto J and Bernstein EF: Molecular mechanisms of cutaneous
aging: Connective tissue alterations in the dermis. J Investig
Dermatol Symp Proc 3: 41-44, 1998.
2. de Rigal J, Escofer C, Querleux B, Faivre B, Agache P and
Lévêque JL: Assessment of aging of the human skin by in vivo
ultrasonic imaging. J Invest Dermatol 93: 621-625, 1989.
3. El-Domyati M, Attia S, Saleh F, Brown D, Birk DE, Gasparro F,
Ahmad H and Uitto J: Intrinsic aging vs. photoaging: A
comparative histopathological, immunohistochemical, and ultra-
structural study of skin. Exp Dermatol 11: 398-405, 2002.
4. McCullough JL and Kelly KM: Prevention and treatment of skin
aging. Ann N Y Acad Sci 1067: 323-331, 2006.
5. Farris PK: A review of the science behind the claims. Cosmetic
Dermatol 16: 59-70, 2003.
6. Chirita RI, Chaimbault P, Archambault JC, Robert I and
Elfakir C: Development of a LC-MS/MS method to monitor
palmitoyl peptides content in anti-wrinkle cosmetics. Anal Chim
Acta 641: 95-100, 2009.
7. Feher P, Vecsernyes M, Fenyvesi F, Varadi J, Kiss T, Ujhelyi Z,
Nagy K and Bacskay I: Topical application of Silybum marianum
extract. Arad Med J 14: 5-8, 2011.
8. Nachbar F and Korting HC: The role of vitamin E in normal and
damaged skin. J Mol Med (Berl) 73: 7-17, 1995.
9. Stiller MJ, Bartolone J, Stern R, Smith S, Kollias N, Gillies R
and Drake LA: Topical 8% glycolic acid and 8% L-lactic acid
creams for the treatment of photodamaged skin. A double-blind
vehicle-controlled clinical trial. Arch Dermatol 132: 631-636, 1996.
10. Rattan SI and Clark BF: Kinetin delays the onset of ageing
characteristics in human fibroblasts. Biochem Biophys Res
Commun 201: 665-672, 1994.
Figure 5. Improvement rates of L* value after applying test materials. Data
were presented as means ± standa rd deviation. A paired t-test was performed
to determine statistical signicant results. *P<0.05, vs. th e con trol.
Figure 6. Improvement rates of a* value after applying test materials. Data
were presented as means ± standa rd deviation. A paired t-test was performed
to determine statistical signicant results. *P<0.05, vs. th e con trol.

HAHN et al: EVA LUATION OF ANT I-AGING EFFECTS OF COSMETIC FORMULATIONS ON AGED HUMAN SKIN
117 6
11. Lintner K: Promoting ECM production without compromising
barrier. Ann Dermatol Venereol 129: 1S105, 2002.
12. Mas-Chamberlin C, Lintner K, Basset L, Adhoute H and
Revuz J: Relevance of antiwrinkle treatment of a peptide:
4 months clinical double blind study vs excipient. Ann Dermatol
Venereol 129: 1S456, 2002.
13. Maquart FX, Siméon A, Pasco S and Monboisse JC: Regulation
of cell activity by the extracellular matrix: The concept of
matrikines. J Soc Biol 193: 423-428, 1999 (In French).
14. Robinson LR, Fitzgerald NC, Doughty DG, Dawes NC, Berge CA
and Bissett DL: Topical palmitoyl pentapeptide provides
improvement in photoaged human facial skin. Int J Cosmet
Sci 27: 155-160, 2005.
15. Kshirsagar A, Ingawale D, Ashok P and Vyawahare N: Silymari n:
A Comprehensive Review. Phcog Rev 3: 126-134, 2009.
16. Ra sul A and Akhtar N: Anti-agi ng potential of a crea m containing
milk thistle extract: Formulation and in vivo evaluation. African
Journal of Biotechnology 11: 1509-1515, 2014.
17. Packer L and Valacchi G: Antioxidants and the response of skin
to oxidative stress: Vitamin E as a key indicator. Skin Pharmacol
Appl Skin Physiol 15: 282-290, 2002.
18. Black HS, Lenger WA, Gerguis J and Thornby JL: Relation of anti-
oxidants and level of dietary lipid to epidermal lipid peroxidation
and ultraviolet carcinogenesis. Cancer Res 45: 6254-6259, 1985.
19. Chow CK: Increased activity of pyruvate kinase in plasma of
vitamin E‑decient rats. J Nutr 105: 1221‑1224, 1975.
20. Djerassi D, Machlin KJ and Nocka C: Vitamin E: biochemical
function and its role in cosmetics. Drug Cosmet 1: 29-34, 1986.
21. Furuse K: Vitamin E: Biological and clinical aspects of topical
treatment. Cosmetics Toiletries 102: 99-116, 1987.
22. Horio T and Okamoto H: Oxygen intermediates are involved
in ultraviolet radiation induced damage of Langerhans cells.
J Invest Dermatol 88: 699-702, 1987.
23. Binic I, Lazarevic V, Ljubenovic M, Mojsa J and Sokolovic D:
Skin aging: Natural weapons and strategies. Evid Based
Complement Alternat Med 2013: 827248, 2013.