Study of active ingredients in black soybean sprouts and their safety in cosmetic use

Active ingredients in different lengths of black soybean sprouts were extracted with water. Concentrations of the main proteins and polysaccharides were determined by the Forint phenol assay and phenol-sulfuric acid assay, respectively. Anti-oxidizing capacities of the extracts were measured in vitro using the DPPH scavenging test and whitening capacity was measured in vitro using the tyrosinase inhibition test. The effects of the bean sprout extracts on human skin fibroblasts damnified by H₂O₂ were studied using an MTT colorimetric assay. The safety of the extracts was determined using the red blood cell (RBC) test, chick chorioallantoic membrane (CAM) assay and human patch test. Results show that DPPH radical scavenging rates at different shoot lengths were all greater than 95%, while the tyrosinase inhibition capacity of the extracts reached 98%. Hemolysis rate in all extracts were lower than 10%, below the 20% regulatory limit for the RBC test. No signs of allergic reactions were observed in the human patch tests. The optimum extract was obtained from bean sprouts grown to 0.5 cm. Extracts of black bean sprouts are safe and can be used as additives in anti-aging and whitening cosmetic products.