This study aimed at evaluating the antioxidative activities and the safety of 50% ethanolic extract from red bean fermented by Bacillus subtillis IMR-NK1. The antioxidative activities, including alpha,alpha-diphenyl-beta-picryl-hydrazyl (DPPH) radicals scavenging effects, Fe(2+)-chelating ability, and reducing power, were studied in vitro. It was found that the antioxidative activity increased with the concentrations of the extract to a certain extent and then leveled off as the concentration further increased. As compared to the commercial antioxidants, the fermented red bean extract showed less scavenging effect on the DPPH radical and reducing power than alpha-tocopherol and BHT, but better Fe(2+)-chelating ability. No mutagenicity or toxicity effect toward all tester strains was found in the 50% ethanolic extract of fermented red bean by means of the Ames test. The results suggested that the 50% ethanolic extract was safe in genotoxicity.

Essential oils extracted from aromatic plants exhibit important biological activities and have become increasingly important for the development of aromatherapy for complementary and alternative medicine. The essential oil extracted from Cinnamomum cassia Presl (CC-EO) has various functional properties; however, little information is available regarding its anti-tyrosinase and anti-melanogenic activities. In this study, 16 compounds in the CC-EO have been identified; the major components of this oil are cis-2-methoxycinnamic acid (43.06%) and cinnamaldehyde (42.37%). CC-EO and cinnamaldehyde exhibited anti-tyrosinase activities; however, cis-2-methoxycinnamic acid did not demonstrate tyrosinase inhibitory activity. In murine B16 melanoma cells stimulated with α-melanocyte-stimulating hormone (α-MSH), CC-EO and cinnamaldehyde not only reduced the melanin content and tyrosinase activity of the cells but also down-regulated tyrosinase expression without exhibiting cytotoxicity. Moreover, CC-EO and cinnamaldehyde decreased thiobarbituric acid-reactive substance (TBARS) levels and restored glutathione (GSH) and catalase activity in the α-MSH-stimulated B16 cells. These results demonstrate that CC-EO and its major component, cinnamaldehyde, possess potent anti-tyrosinase and anti-melanogenic activities that are coupled with antioxidant properties. Therefore, CC-EO may be a good source of skin-whitening agents and may have potential as an antioxidant in the future development of complementary and alternative medicine-based aromatherapy.

This study aimed at evaluating the antioxidative activity of crude hsian-tsao leaf gum extracted by sodium bicarbonate solutions and precipitated by 70% ethanol. The antioxidative activities, including the radical-scavenging effects, Fe(2+)-chelating ability, and reducing power as well as the inhibition of FeSO(4)-H(2)O(2)-induced malondialdehyde formation in rat tissue homogenate were studied in vitro. It was found that the antioxidative effect provided by hsian-tsao leaf gum was strongly concentration dependent. In general, the antioxidative activity increased with increasing gum concentration, to a certain extent, and then leveled off with further increase in gum concentration. A concentrtaion-dependent kinetics for the rate of change in antioxidative activity was proposed. The antioxidative activity constant (k) and the half-inhibition concentration (IC(50)) for each antioxidative reaction studied were calculated. From a comparison of the IC(50) values for different antioxidative reactions, it seemed that hsian-tsao leaf gum was more effective in scavenging superoxide radicals than chelating Fe(2+) or scavenging alpha,alpha-diphenyl-beta-picrylhydrazyl (DPPH) radicals. As compared to the commercial antioxidants, hsian-tsao leaf gum showed less scavenging effect on the DPPH radical and reducing power but better superoxide radical-scavenging effect and Fe(2+)-chelating ability than alpha-tocopherol and BHT.

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