Investigating Antibacterial and Antioxidant Activity of Inocutis levis Extracts and Evaluating its Phenolic Compounds

Inocutis levis is a polypore basidiomycete from the Hymenochaetaceae family. Members of this family have well-known medicinal properties. Recently, anti-diabetic and anti-hypercholesterolemic effects of I. levis have been reported. This study aimed to evaluate antibacterial activities and antioxidant properties of the extracts of I. levis.

After the sampling and fungus identification, the methanolic, ethanolic, and aqueous extracts of the dried fruiting bodies of I. levis were prepared. The antioxidant activities were determined by DPPH method, and antibacterial activities by microdilution method against some gram-positive and gram-negative bacteria. Furthermore, the identification and quantification of phenolic and flavonoid compounds of the extracts were investigated by spectrophotometers and HPLC.

The results showed that the methanolic extract had the highest DPPH scavenging activity, with an IC50 value of 555 µg/ml. The ethanolic and methanolic extracts showed the same antibacterial effects, and Streptococcus mutansATCC35665 was more sensitive than other bacteria, with the MIC and MBC values of 12.5 and 25 mg/ml, respectively. Total phenolic (34.15mg gallic acid) and total flavonoid contents (5.4mg quercetin) per 1 gram dry methanolic extract were higher than other extracts. Furthermore, in the HPLC analysis, ascorbic acid, resorcinol, caffeic acid, catechin and, vanillic acid were determined.

This is the first study presenting the antibacterial and antioxidant properties of I. levis. The results can be considered for future studies in the design of new antibiotics and antioxidant compounds from natural resources applying native fungi.