Introduction
The cellular aging process occurs continuously over time after birth deteriorating not only biofunctions of internal organs but also physical appearances. Indeed, the aging sign of humans is markedly observed through aging skin appearances such as skin wrinkles, dry, sagging and rough skin that is principally attributed to both intrinsic and extrinsic factors generating mainly reactive oxygen species or free radicalsThailand is regarded as one of the biodiverse regions of the world. A number of scientific research studies revealed that a vast diversity of Thai traditional herbs and plants exerted notable in vitro and in vivo anti-aging properties in several modes of action. From the related literature, these three Thai herbal extracts were trusted to be promising active ingredients for anti-skin aging purposes. However, no evidence has proven the anti-aging combination effect of these three extracts which potentially promote anti-aging clinical outcome. As a result, the present study aimed to firstly optimize the multi-extract combination exerting a desirable antioxidant property by means of statistical method. An anti-aging emulsion containing the optimized multi-extract combination was subsequently developed and evaluated for its physical characteristics, stability as well as confirmed its in vivo anti-skin aging clinical efficacy by means of a randomized, double-blind, placebo-controlled trial conducting among 60 aged women. In addition, skin tolerance and safety profile of the product was investigated using the in vivo patch test among the volunteers.