Skin Brightening Efficacy of Grammatophyllum speciosum: A Prospective, Split-Face, Randomized Placebo-Controlled Study

Grammatophyllum speciosum Blume is widely used as a traditional herbal medicine throughout Asia. The purpose of the study was to investigate the clinical skin-whitening effect and in vitro evaluation of the underlying mechanism of G. speciosum pseudobulb ethanolic extract (GSE). The study examined the inhibitory effects of GSE on B16F10 tyrosinase activity, melanin content, and mushroom tyrosinase. The GSE was developed into a hydrogel formulation and evaluated for its stability. A randomized, double-blind, placebo-controlled study of hydrogel containing GSE was conducted on healthy volunteers to examine the skin irritation and skin-whitening effect using Maxameter® MX 18 and Visioface® RD. GSE significantly inhibited the formation of melanin in B16F10 cells without affecting the tyrosinase enzyme and mushroom tyrosinase. After 6 months, the hydrogel containing a 0.5% (w/w) GSE formulation showed good physicochemical stability. There was no skin irritation caused by GSE hydrogel in participants. GSE hydrogel significantly increased melanin reduction activity by 8.285% after 56 days of treatment, whereas the hydrogel base was −0.949%. The results revealed that G. speciosum decreased melanogenesis in B16F10 cells and increased melanin-reduction activity in our clinical study. Hence, G. speciosum could be used in skincare products as a form of dermatological-whitening agent.