Characterization, biological activities and safety evaluation of different varieties of Thai pigmented rice extracts for cosmetic applications

Abstract

© 2017. The study aimed to evaluate the total phenolic and flavonoid contents, biological activities and safety of different varieties of Thai pigmented rice for cosmetic applications. Five different varieties of Thai pigmented rice included Sang-Yod (SY), Mun-Poo (MP), Hom-Nin (HN), Rice Berry (RB), and Luem-Pua (LP). The rice grains were extracted using 50% ethanol and dried under vacuum. The total phenolic and flavonoid contents of rice extracts were in the range of 128-322 mg GAE/g extract and 86-341 mg CE/g extract, respectively. LP extract showed the highest values for the total phenolic and flavonoid contents. Based on the antioxidant activities, LP showed the highest radical scavenging activities both DPPH and ABTS assays. Concerning the anti-tyrosinase activity, all rice extracts exhibited a weak performance. In contrast, all rice extracts strongly inhibited the formation of advanced glycation end products (AGEs), the activity of collagenase and elastase enzyme. The obtained results from UV scanning showed the potential of rice extract as a UV absorber. The cytotoxicity using human fibroblast cell indicated the safe use of all rice extracts for topical administration. At the concentration of 400 μg/mL, the cell viability was higher than 50% for all rice extracts and LP showed the highest cell viability compared to others. As a result, rice extracts are a promising ingredient for cosmetics, especially for the anti-aging application.