Strong Radical Scavenging Macrofungi from the Dry Zone Forest Reserves in Sri Lanka

Abstract

Natural metabolites produced by macro fungi are of great interest as potential antioxidant defensive agents to reduce the oxidative damage caused by free radicals. Primarily, phenolic and flavonoid type metabolites have gained major importance due to the strong capacity of scavenging free radicals. The study was mainly focused to investigate the natural antioxidant properties of macro fungi found in Sri Lankan dry zone forest reserves using DPPH radical scavenging assay and to find out the contribution of phenol and flavonoid substances towards their antioxidant capacity. EC50 values of all extracts were below 1.2 mg/ml. Among the analyzed specimens, Phellinus repandus and Inonotus porrectus showed the most potent antioxidant activities having EC50 of 7.91 ± 1.38 µg/ ml and 19.70 ± 0.17 µg/ ml, respectively. Ten fungal forms exhibited EC50 < 300 µg/ ml and eighteen showed a mean values of EC50 in the range of 300-1200 µg/ ml. Further, P. repandus and I. porrectus also exhibited the highest level of total phenols and flavonoids. EC50 values of the species studied were inversely related to the total phenol and flavonoid contents. The analyzed macrofungi specimens exhibited high antioxidant power highlighting their potential as therapeutically useful antioxidant agents. Particularly, P. repandus and I. porrectus could be an important source of novel antioxidant compounds. In addition, phenol and flavonoid compounds largely contribute to the scavenging activity of studied macrofungi.