In vitro investigation of antimicrobial, enzyme inhibitory and free radical scavenging activities of Inula salicina L.

Abstract

In this study, in vitro biological activities and total phenol/flavonoid contents of methanol extract (ISM) and its hexane (ISH), chloroform (ISC), ethyl acetate (ISEA) and aqueous methanol (ISAM) fractions obtained from aerial parts of Inula salicina were investigated. ISEA showed the highest antioxidant activity against DPPH and ABTS radicals with an IC50 value of 0.014 mg ml-1for both assays. ISEA exhibited a good anti-inflammatory activity with an IC50 value of 0.060 mg ml-1. ISEA was found to exhibit a moderate level of antidiabetic activity against α amylase enzyme with an IC50 value of 0.290 mg ml-1. ISEA and ISM presented low and moderate inhibitory activity against acetylcholinesterase and butyrylcholinesterase enzymes with IC50 values of 0.577 and 0.279 mg ml-1, respectively. ISC with MIC values of 78 and 156 µg ml-1 displayed a significant antimicrobial activity against Staphylococcus aureus and S. epidermidis, respectively. Almost all extracts had moderate effect against Candida species. The highest total phenolic and flavonoid contents were determined in ISEA with 574.8 mg GAE (gallic acid equivalent) g-1 extract and 30.48 mg QE (quercetin equivalent) g-1 extract, respectively. These results showed that ISEA had a good antioxidant and anti-inflammatory activity with moderate α-amylase and butyrylcholinesterase inhibitory activity. Also, ISC exhibited a significant antimicrobial activity against Staphylococcus species.