We evaluated the antioxidant activity and melanogenic effects of black soybean ethanol extracts, including Rhynchosia nulubilis bean ethanol extract (RNBEE), R. nulubilis leaf ethanol extract (RNLEE), R. volubilis bean ethanol extract (RVBEE), and R. volubilis leaf ethanol extract (RVLEE). The total polyphenol contents of RNBEE, RNLEE, RVBEE, and RVLEE were 16.0, 57.7, 365.9, and 260.1 mg/g, respectively. The total flavonoid contents of RNBEE, RNLEE, RVBEE, and RVLEE were 40.4, 91.7, 84.7, and 216.5 mg/g, respectively. The electron-donating abilities of RNBEE, RNLEE, RVBEE, and RVLEE at 1,000 μg/mL were 32.4%, 12.7%, 83.5%, and 84.5%, respectively. RNBEE, RNLEE, RVBEE, and RVLEE at 50 μg/mL significantly increased (p < 0.01) melanin contents by 30.4%, 32.1%, 35.5%, and 37.4%, respectively, compared to that of the control. RNBEE, RNLEE, RVBEE, and RVLEE at 50 μg/mL significantly increased (p < 0.01) intracellular tyrosinase activity by 18.4%, 21.8%, 21.5%, and 21.1%, respectively, compared to that of the control. These results demonstrated that black soybean ethanol extracts promote melanogenesis in melan-a cells. Among the black soybean ethanol extracts, R. volubilis was found to be more effective than R. nulubilis, and leaf extract was found to be more effective than bean extract. The potential mechanism underlying the hyperpigmentation effects of black soybeans is the promotion of tyrosinase activity.

The effects that ultraviolet rays elicit on collagen synthesis and degradation are the most common causes of wrinkle formation and photo-aging in skin. The objectives of this study were to evaluate the effects of Angelica acutiloba root ethanol extract (AAEE) to promote collagen synthesis and inhibit collagen degradation in human dermal fibroblasts. By examining total polyphenol and flavonoid contents, electron donating ability, radical scavenging activity, and superoxide dismutase-like activity, we found that AAEE exhibited fairly good antioxidant activity. Treatment with AAEE significantly increased type I procollagen production by cultured fibroblasts, as well as reduced ultraviolet-induced matrix metalloproteinase-1 (MMP-1) expression and MMP-2 activity in a dose-dependent manner (p < 0.05). In addition, AAEE significantly increased TIMP-1 mRNA expression (p < 0.05), although without an associated dose-dependent increase in TIMP-1 protein expression. In summary, we suggest that AAEE may be a potentially effective agent for the prevention or alleviation of skin-wrinkle formation induced by ultraviolet rays.