Background: Both intrinsic and environmental factors play a role in premature ageing of the skin. Natural extracts have been extensively used to reduce the signs of ageing in recent years. Pterostilbene is a natural analog of resveratrol with therapeutic properties against numerous diseases mainly due to its ability to reduce reactive oxygen species. Methods: We studied the anti-aging and skin brightening effect of a 0.4% formulation of natural pterostilbene in healthy volunteers (N=38) in an open-label, single-arm, monocentric study for 8 weeks. The melanogenesis inhibitory, anti-tyrosinase and anti-collagenase and anti-elastase properties of pterostilbene were evaluated in vitro. Results: Natural pterostilbene showed significant inhibition of melanogenesis in vitro. Pterostilbene cream (0.4%) was highly effective in reducing markers of aging and induces even skin tone. The product was effective in reducing wrinkles and fine lines, improved skin hydration elasticity and showed no adverse effects. Conclusion: Our results suggest that natural pterostilbene is a safe and effective ingredient for use in cosmetic preparation to reduce the markers of skin ageing and brighten the skin tone. Trial Registration: Clinical Trial Registration India Identifier CTRI/2019/01/017160 [Registered on 18/01/2019].

Ultraviolet (UV) rays and its harmful effects have always been a concern to skin health. Sunscreen and sunblock prevent the harmful effects of UV radiation on the skin. Sun Protection Factor (SPF) is an indication of the sun-protective capacity of an ingredient. There is an ever increasing interest in the cosmetic industry for developing novel functional ingredients from natural sources. The purpose of this study was to determine in-vitro and in vivo SPF of natural 90% pterostilbene extracted from the dried heartwood of Pterocarpus marsupium (Indian Kino). The SPF of purified pterostilbene and a formulation containing 0.4% pterostilbene was determined In Vitro using a UV spectrophotometer. Pterostilbene had an SPF of 21.73 ± 0.06, while the cream formulation had an SPF of 8.84 ± 0.01. The in vivo SPF of the 0.4% pterostilbene cream in humans was found to be 6.2 ± 1.30. Primary skin irritation tests in human subjects showed the formulation was safe and had no irritation potential. Pterostilbene was also found to have significant antioxidant activity as determined by free radical scavenging assays in vitro. These results suggest that natural pterostilbene is an antioxidant and shows SPF value both in-vitro and in the human clinical study and thus could be used as an ingredient in topical sun-protective formulations.