SOOTHING EFFECT OF POGOSTEMON CABLIN EXTRACT 429 FACE CAPSAICIN–INDUCED STINGING TEST For thi s clinical study, 20 volunteers were enrolled after having read the information re- lated to the study and signed the informed consent form. All volunteers had sensitive skin and were divided in two groups of 10, homogeneous in age and gender. For 28 d, on all the faces, one group applied a placebo cream and one group applied a cream containing the patchouli extract at 1%. The study was performed in double blind. The stinging test was carried out on the fi rst day of the study (D0), before cream application and 28 d after cream applications (D28). The test consisted in applying 0.01% of capsaicin diluted in 10% ethanol to one nasolabial fold and 10% ethanol to the other during 30 s. Just after the exposure, the subjects recorded the sensations of stinging each minute during 10 min on a 0- to 4-interval scales (0 = no sensation, 1 = slight stinging, 2 = moderate stinging, 3 = intense stinging, and 4 = very intense stinging). At the end, the 11 scores were summed to give a score of skin sensitivity. STATISTICAL ANALYSIS All experiments have be en repeated at least twice with cells and skin coming from differ- ent plastic surgery, and the quantifi cation of the fl uorescence was performed by measuring the fl uorescent intensity of the staining, which was normalized by the epidermis or cell area. Statistical analyses were performed using Excel 365 (Microsoft, Redmond, WA). Difference between two means was performed with Student’s t-test. A p-value d 0.05 was considered statistically signifi cant (*), p-value d 0.01 as very signifi cant (**), and p-value d 0.005 as highly signifi cant (***). For the clinical test, statistical analysis was performed using JMP® 14 (SAS Inc, Cary, NC) software. The homogeneity of the gender between the two groups was performed using the χ2 test, and the homogeneity of the age was confi rmed using the Mann–Whitney test. Concerning the statistical analysis of stinging values, the scores, which were used as a basis, concerned the difference (D28–D0) for the patchouli extract and placebo group using Wilcoxon test (after verifying the data followed a normal distribution or not with the Shapiro–Wilk test). RESULTS THE CB2 RECEPTOR ACTIVATION SHOWS RESISTANC E TO UV- INDUCED SKIN INFLAMMATION Because of the potential role of cannabinoids in hu man skin infl ammation, we investigated whether the antagonist AM630 would exhibit an amplifi ed susceptibility to UVB- induced infl ammation in human skin biopsies. Histologic analysis indicated that UVB- treated human skin showed a pronounced infl ammation with the emergence of structural damages and sunburn cells (Figure 1A). Exposure to AM630 (3 h) before UVB irradiation showed a very damaged structure with an important epidermal erosion, whereas the epi- dermis exposed to AM1241 (3 h) was far more resistant to UVB-induced infl ammation (Figure 1A). In a second time, skin was treated with the patchouli extract during 48 h after UVB irradiation. The biopsies were treated or not during 3 h with AM630 prior UVB irradiation. The patchouli extract preserved the skin from UVB, compared with the placebo condition (Figure 1B). The antagonist AM630 was able to partially block the protective effect of the patchouli extract on skin preservation.
JOURNAL OF COSMETIC SCIENCE 430 PATCHOULI EXTRACT INCREASES CANNABINOID RECEPTOR 2 AND THE β-ENDORPHIN OPOID Several lines of evidence demonstrate that phytocann abinoids can exert various biological effects in the skin. Immunohistochemistry for cannabinoid receptor 2 on human skin sections (Figure 2A) showed primary localization of the receptor in the epidermis, although some Figure 1. Stimulation or inhibition of cannabinoid receptor 2 in UVB-irradiated human skin. (A) Hematoxylin– eosin staining of h u man skin sections of skin treated with PBS buffer, AM630, AM1241, 3 h before UVB irradiation. Biopsies were maintained in culture 48 h after UVB irradiation, and then formalin-fi xed and paraffi n-embedded. (B) Hematoxylin–eosin staining of human skin sections treated or not with AM630, 3 h before UVB irradiation. Topic application of placebo and patchouli extract was performed after the irradia- tion. Biopsies were maintained in culture 48 h after UVB irradiation, and then formalin-fi xed and paraffi n- embedded (objective ×20).
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