Scopoletin was isolated from Sinomonium acutum and studied using four experimental models designed to assess antioxidant properties. The results indicated that scopoletin scavenged superoxide anion in the xanthine/xanthine oxidase reaction system in a concentration-dependent manner, but did not inhibit xanthine oxidase. Scopoletin may therefore be responsible for the superoxide anion scavenging activity seen in Sinomonium acutum extracts and may be of use in preventing superoxide anion-induced damage in vivo.

Bioassy-directed fractionation of a culture broth of Penicillium citrinum F5 led to the isolation of a novel antioxidant 2,3,4-trimethyl-5,7-dihydroxy-2,3-dihydrobenzofuran (1), together with gentisic acid (2), and their structures were determined on the basis of spectroscopic data. In the 1,1-diphenyl-picryl-hydrazyl (DPPH) assay system, compounds 1 and 2 showed free radical scavenging activity with IC(20) values of 10.39 and 4.26 microM, respectively.

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