Antioxidant Activities In Vitro of Ethanol Extract and Fractions from Mushroom, Lenzites Betulina

The antioxidant potential of different fractions of Lenzites betulina was investigated. Fraction 2 showed the highest antioxidant activity in the 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydroxyl (OH) radical-scavenging assays. Three natural p-terphenyls were identified in this fraction. The structure of a new natural compound was established as 2-phenyl-[1H-2-benzopyran][4,3-e][p]benzoquinone in addition to two other compounds, 2,5-diphenyl-3,6-dimethoxy-p-benzoquinone and 2-phenyl-3-methoxy-[1H-2-benzopyran][4,3-e][p]benzoquinone that have been previously reported in L. betulina. The antioxidant activities of these p-terphenyls were evaluated by DPPH and OH radical-scavenging assays. 2-phenyl-3-methoxy-[1H-2-benzopyran][4,3-e][p]benzoquinone was the most active in the OH radical-scavenging test (IC 50 = 37.69 μg/mL) and showed little inhibition in the DPPH assay. The chemical components of L. betulina therefore have some antioxidant capacities, and this species could be used as a potential source of new natural antioxidants. Practical Applications Lenzites betulina has been used as a kind of medicinal fungus in China. In order to find its potential application, the antioxidant potential of L. betulina was investigated. It was found that the total ethanol extracts and the fraction 2 of L. betulina showed strong antioxidative capacity in the 2, 2-diphenyl-1-picrylhydrazyl and hydroxyl (OH) radical-scavenging assays. The OH radical-scavenging activity of the fraction 2 (IC 50 = 19.42 ± 0.4 μg/mL) was similar to that of ascorbic acid (IC 50 = 20.55 ± 0.2 μg/mL). Meanwhile, three natural p-terphenyl (a new natural compound and two known compounds) were identified in this fraction. Compound 2 showed the most activity in the OH radical-scavenging test (IC 50 = 37.69 μg/mL), so this species could be used as a potential source of new natural antioxidants.