Phytochemical Investigation of Sanguisorba minor Scop. and α-Glucosidase Inhibitory Activity: a Bio-Guided Approach

Background and objectives: Sanguisorba minor Scop. is a perennial species widely distributed throughout Iran. Its leaves are commonly used in salads, beverages, and various dishes. Sanguisorba minor has been used in traditional medicine to treat bleeding, diarrhea, duodenal ulcers, and intestinal infections. The present study aimed to isolate the non-volatile constituents of S. minor and evaluate their anti-diabetic activity through an α-glucosidase inhibition assay. Methods: Phytochemical analysis of the methanol extract from the whole plant was conducted using column chromatography with silica gel and Sephadex LH-20 as the stationary phase. The isolated compounds were evaluated for their α-glucosidase inhibitory activity, and the most potent compound was further examined through in silico studies. Results: Three compounds, including chlorogenic acid (1), 1-O-protocatechuoyl-xylose (2), and apigenin (3), were isolated and identified using 1H-NMR and 13C-NMR spectral analyses. The α-glucosidase inhibitory activity assay demonstrated good inhibition, with results comparable to acarbose (IC50 = 0.75 mM), used as the positive control. The isolated compounds, including chlorogenic acid, 1-O-protocatechuoyl-xylose, and apigenin, exhibited IC50 values of 3.20, 1.00, and 1.30 mM, respectively. Furthermore, the kinetic studies of the isolated compounds revealed an uncompetitive inhibition pattern for compound 1, while compounds 2 and 3 showed a competitive mechanism. Additionally, in silico studies validated the construction of various hydrogen bonding interactions between the most potent inhibitor, compound 2, and the enzyme active site. Conclusion: This study reported the isolation and identification of three bioactive compounds from S. minor, emphasizing their α-glucosidase inhibitory activity.