Antioxidant activities of extracts and metabolites isolated from the fungus Antrodia cinnamomea.

Three different solvent partitions (n-hexane, ethyl acetate [EtOAc] and n-BuOH) of the culture broth from Antrodia cinnamomea were assayed with two different radical scavenging methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and superoxide radical scavenging (SOD) assay. The EtOAc layer exhibited the best antioxidant activity. Two major antioxidant metabolites were isolated from the active EtOAc layer. The antioxidant activities of compounds 1-6 were further evaluated by DPPH, SOD and trolox equivalent antioxidant capacity (TEAC) assays. Compounds 3 and 5 showed stronger free radical scavenging than the reference BHA, ED₅₀ = 1.36 and 34.24 µM. Compound 5 displayed moderate SOD activity (ED₅₀ = 310.0 µM), and its antioxidant capacity of TEAC value was 2.2 mM trolox equivalency.