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To investigate the antioxidative and antimicrobial effects of Rhus verniciflua Stokes (RVS) ethanolic extract, the extract was subsequently fractionated into four portions using distilled water, 99% ethanol, 70% ethanol and 5% acetic acid as elution buffers through silica gel column chromatography (4×28㎝, 22Å, 28-200 mesh). In antioxidant assay, the hydroxyl radical-mediated cytotoxicity in splenocytes or neuron cell cultures was clearly reduced by supplementation of extract eluted with distilled water (EDW). Comparing the toxic level against exposure of hydroxyl radical in the cell cultures, neuron cells were shown to be more damaged than splenocytes under the same condition. Moreover, EDW was shown as an antioxidant protecting against nitric oxide-induced cytotoxicity in neuron cells, while other samples fractionized from RVS ethanolic extract were less efficient. In antimicrobial test, EDW was found to have strong inhibitory effects against the growth of E. coli XLI-Blue or JA221 in both suspension and agar plate cultures. Laccase assay was resulted that EDW had more specific activity of lactase than those of other samples. From these results, we concluded that a reliable relationship existed between lactase activity and antioxidant or antimicrobial activity. The more the samples contained lactase activity, the more they showed antioxidant and antimicrobial effects. Therefore, it is believed that RVS ethanolic extract could be used as a strong antioxidant as well as an antimicrobial agent to preserve foods and feeds as a natural nutritive substance.
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