Phytochemicals, Antioxidant, and Antidiabetic Effects of Ranunculus hirtellus Aerial Parts and Roots: Methanol and Aqueous Extracts

Abstract

Ranunculus hirtellus, also known as crowfoot (buttercup), has a rich tradition of use in various biological contexts. While antibacterial studies on extracts from this plant have been conducted, the phytochemical composition, antioxidant properties, and antidiabetic effects remain unexplored. In this study, the phytochemical, antioxidant, and antidiabetic effects of its methanol and aqueous extracts were investigated. Our approach involved gas chromatography-mass spectrometry (GC/MS), alongside quantitative and qualitative methods, for phytochemical profiles. Additionally, concerning biological activities, the antioxidant effect was assessed through 2, 2-diphenyl-pieryl hydrazyl (DPPH) and 2, 2′-azino-bis (3-ethylbenzothiazoline-6-sulfonate) (ABTS) assays, while the antidiabetic effect was examined through the α-amylase inhibitory assay. The chloroform, ethyl acetate, and n-hexane extracts of R. hirtellus revealed the presence of 14 distinct compounds. In the methanol extract, sterols, quinones, glycosides, lactones, lignin, and flavonoids were identified. The aqueous extract contained sterols, alkaloids, glycosides, triterpenes, terpenoids, quinones, leucoanthocyanins, and lactones. The total flavonoid content (TFC), total phenolic content (TPC), total tannin content (TTC), and reducing sugar content (RDC) were determined in plant extracts, and a linear relationship was found between these parameters. Additionally, the TTC, TPC, and TFC values for both extracts hovered around 0.3786, 0.0476, and 0.1864 μg/mL, respectively, across all plant concentrations, while RDC ranged from 0.9336 to 1.0119 μg/mL in all four extracts. In vitro assays demonstrated dose-dependent antidiabetic activity in both methanolic and aqueous extracts by inhibiting α-amylase. Furthermore, the antioxidant activity observed in the DPPH assay was greater in the aqueous extract compared with the methanolic extract. In addition, the ethyl acetate extract exhibited the highest inhibition among chloroform and n-hexane in the ABTS assay. The results suggest that R. hirtellus can be a potential source of natural antioxidants and antidiabetic agents, and further studies are warranted to investigate the underlying mechanisms of its therapeutic effects.