Antimicrobial, antioxidant, antimutagenic activities, and phenolic compounds of Iris germanica

Abstract

This study investigated the antimicrobial, antioxidant and antimutagenic properties and phenolic compounds of ethanolic extracts of the aerial parts and rhizomes of the iris I. germanica L. While previous studies have examined the antimicrobial and antioxidant properties of I. germanica, to our knowledge, this is the first study to report on the antimutagenic activity and phenolic compounds of ethanolic extracts of the plant's aerial parts and rhizomes.Antimicrobial activity was evaluated using the disc diffusion method. I. germanica was found to exhibit only limited antimicrobial activity against Bacillus subtilis ATCC 6633.Antioxidant activity was evaluated according to free-radical scavenging (DPPH), total antioxidant activity and total phenolic content. The radical scavenging activity of the ethanolic extracts of the aerial parts and rhizomes of I. germanica were found to have IC50 values of 5.38 and 12.3mg/ml, respectively, whereas total antioxidant activity of the extracts (at 3.15mg/ml) was 98.7% and 97.4%, respectively, and total phenolic content was 267.36±2.05 and 331.96±1.78mg gallic acid equivalent/g extract, respectively. HPLC analysis of phenolic compounds identified protocatechuic acid (0.356±0.004mg/g extract), chlorogenic acid (0.164±0.0064mg/g extract) and ferulic acid (0.164±0.008mg/g extract) as the main phenolic acids contained in the extract of the aerial parts of I. germanica, whereas chlorogenic acid (2.44±0.036mg/g extract), (+)-catechin (2.14±0.056mg/g extract) and ferulic acid (0.452±0.008mg/g extract) were identified as the main phenolic acids contained in the extract of the rhizome.Antimutagenic activity was assessed using the Ames Salmonella/microsome mutagenicity test. The bacterial mutant strains Salmonella typhimurium TA98 and TA100 were used to determine antimutagenic properties of the test compounds. The ethanolic extract of the aerial parts of I. germanica exhibited antimutagenic effects at 3, and 0.3mg/plate concentrations. Although the rhizomes exhibit antimutagenic effects at 1.5, 0.15 and 0.015mg/plate concentrations.In sum, the findings indicated I. germanica ethanolic extracts possess antioxidant and antimutagenic properties that could have potential value in the fields of medicine and cosmetics; however, only limited antimicrobial activity was observed.