A Comparative Study On The In Vitro Antioxidant And Antimicrobial Potentials Of Three Endemic Ononis L. Species From Turkey

Objectives: In this study, the antioxidant capacity, antimicrobial activity and phenolic contents of aerial parts and roots extracts of three endemic Ononis L. (Leguminosae) species (O. sessilifolia Bornm., O. basiadnata Hub. & Mor., O. macrosperma Hub. & Mor.) were investigated for the first time.Materials and Methods: The phenolic contents of the extracts [water and ethanol (EtOH)] and fractions [dichloromethane, EtOAc and n-butanol] were determined using Folin-Ciocalteu's phenol reagent. Also, their antioxidant capacities were studied using qualitative DPPH center dot (1,1-diphenyl-2-picrylhdrazyl radical) and TBA assays. The antimicrobial activity of these extracts and fractions compared with standard antibiotics were studied using disc diffusion assays against various Gram-positive and Gram-negative bacteria and fungi.Results: The total phenolic contents of the water extracts were found to range between 14.78-80.33 mg/g, and the EtOH extracts ranged from 67.19-145.33 mg/g. EtOAc fractions of the three species were rich in terms of total phenolic contents when compared with other extracts (242.56-620.89 mg/g). The most significant results in the TBA assays were obtained in EtOH extracts of O. macrosperma (IC50 =0.13 +/- 0.17 mu g/mL), O. sessilifolia (IC50=1.41 +/- 0.58 mu g/mL) and root (IC50=1.96 +/- 0.39 mu g/mL).Conclusion: EtOAc fractions rich in phenolic content were also found to be the most effective in antioxidant activity assays. Although all water extracts had no antimicrobial activity, EtOH extracts and n-butanol fractions showed generally moderate activity against bacteria. Some EtOAc fractions except for O. sessilifolia showed less activity against Escherichia coli, Staphylococcus aureus, MRSA and Candida albicans.