A Novel Cassia fistula (L.)-Based Emulsion Elicits Skin Anti-Aging Benefits in Humans

Cassia fistula, a flowering plant in the family of Caesalpinaceae (Fabaceae), is used in traditional medicine for several indications. Nevertheless, too little is known about its effects on skin conditions and skin aging. Therefore, in this pioneering study, the extracts of oil-in-water macro-emulsions containing 5% C. fistula (L.) crude pods (i.e., phyto-active formulation) were optimally developed and compared to the placebo (i.e., emulsions without the crude extract) for assessment of their effects on human skin aging. Healthy adult male volunteers (n = 13) with a mean age of 31 ± 5.5 years (range: 24–47 years) were enrolled after informed written consent. For 12 consecutive weeks, the subjects were directed to use a patch containing the active emulsion on one of their forearms as well as a patch containing the placebo on their other forearm. Biometrological measurements of skin hydration (SH) and transepidermal water loss (TEWL) were performed on both sides of their respective cheeks at time 0 (baseline values), 2, 4, 6, 8, 10 and 12th weeks. Surface evaluation of living skin (SELS) was taken at time 0 (baseline values) or after 1, 2 and 3 months. Topical application of C. fistula extracts showed a significant (p < 0.05) increase in stratum corneum hydration level, a significant enhancement in its water-holding function as well as in its barrier function. Further, significant (p < 0.005) ameliorations of skin aspects were observed (i.e., less roughness, less dryness, less wrinkles). Taken together, our results strongly suggest therapeutic and esthetic potential of C. fistula pod’s extracts to prevent or delay human skin aging. OPEN ACCESS Cosmetics 2015, 2 369