Natural Melanogenesis Inhibitor, Antioxidant, and Collagen Biosynthesis Stimulator of Phytochemicals in Rice Bran and Husk Extracts from Purple Glutinous Rice for Cosmetic Application

The study explored the cosmetic potential of extracts from purple glutinous rice (Oryza sativa L. cv. Pieisu 1 CMU) for skin whitening and anti-aging. The defatted rice bran extract (DFRB) was particularly effective, showing significant inhibition of tyrosinase, comparable to arbutin, and strong antioxidant activity. It also reduced melanin production and protected against collagen degradation, suggesting its utility in dermatocosmetic products targeting skin hyperpigmentation and aging. The antioxidant effects were linked to compounds like oleic acid and quercetin, while collagen protection was comparable to l-ascorbic acid. These findings indicated that rice-processing wastes from this Thai rice cultivar could serve as promising natural ingredients for enhancing skin health.