Antioxidant and antimicrobial activities of four Astragalus species growing wild in Turkey

Abstract

Abstract Objective The objective of the present study was to investigate the phenolic compositions, antioxidant, antimicrobial and cytotoxic activities of four Astragalus species, two of which are endemic to Turkish flora. Methods The total phenolic and flavonoid contents of methanol extracts obtained from four Astragalus species were detected using Folin-Ciocalteu and aluminum chloride colorimetric assays. Their phenolic compositions were identified by Liquid chromatography–mass spectrometry (LC-MS). The antioxidant activity was assayed with phosphomolybdenum, 2,2-diphenyl-1-picrylhydrazyl radical scavenging (DPPH), hydrogen peroxide scavenging, β-carotene bleaching activity, ferric-ion reducing power (FRAP) and cupric ions (Cu2+) reducing antioxidant capacity (CUPRAC) methods. Antimicrobial activities of the extracts were studied by agar well-diffusion assay. The cytotoxic effects of the extracts on MCF-7 (human breast cancer cell lines) were determined by MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazoliumbromide) method. Results The extracts exerted moderate antioxidant and reducing activity with low phenolic contents. The main component in the extracts was determined as ferulic acid. The extracts demonstrated no antibacterial activity except P. aeruginosa. A. talasseus showed the highest cytotoxic activity on MCF-7 during 48 h. Conclusion It is believed that the results of this study will contribute to research recently increasing for the use of natural antioxidant and antimicrobial compounds in many industrial fields such as food, pharmacy and medicine.