Phenolic profile, antioxidant and enzyme inhibitory potential of methanolic extracts from different parts of Astragalus ponticus Pall.

Abstract

This study was designed to document the phenolic profile, antioxidant activity and enzyme inhibitory potential of methanolic extracts of different parts of Astragalus ponticus. The leaves and roots possessed highest total phenolic (26.34 ± 0.50 mg GAEs/g extract) and total flavonoid (49.13 ± 0.51 mg REs/g extract) contents respectively. In vitro antioxidant assay, leaves extract showed highest activity in terms of DPPH radical scavenging (43.64 ± 0.94 mg TEs/g extract), phosphomolybdenum test (1.33 ± 0.14 mmol TEs/g extract); CUPRAC reducing power (64.28 ± 0.90 mg TEs/g extract) and FRAP reducing power (56.79 ± 4.34), while roots extract recorded maximum in ABTS radical cation (98.79 ± 1.95 mg TEs/g extract) assay. All the extracts showed weak enzyme inhibitory on AChE (1.77 ± 0.07–2.29 ± 0.04 mg GALAEs/g extract); BChE (stems and roots only possessed activity); α-amylase (0.56 ± 0.01–0.60 ± 0.01 mmol ACEs/g extract). On the other hand, the extract showed moderate to strong inhibition towards α-glucosidase (3.66 ± 0.02–22.81 ± 0.01 mmol ACEs/g extract) and tyrosinase (2.97 ± 0.84–15.63 ± 1.83 mg KAEs/g extract). The correlation analysis revealed a strong significant positive correlation between antioxidant activity and total phenolic content and luteolin concentration. Further the phytochemicals such as Hesperidin, p-coumaric acid and benzoic acid exert strong correlation with α-glucosidase inhibition. The findings indicate that the extracts from different parts of Astragalus ponticus might be considered as a novel source of antioxidant and enzyme inhibitory compounds in food and pharmaceutical industries.