Chemical profiling of Astragalus membranaceus roots (Fish.) Bunge herbal preparation and evaluation of its bioactivity

Astragalus membranaceus (Fish.) Bunge is a perennial herb distributed in the northern part of China and its roots, namely Hang qi, are included as natural ingredient in dietary supplement formulations commonly used to treat different disorders such as respiratory infections, diabetes, and heart failure. The availability of a simple method for the determination of the quality of Astragalus herbal preparations could be a challenging issue for commercial purposes. In this study, a LC-MS/MS based approach was used to characterize specialized metabolite recovery of three commercial hydroalcoholic extracts of A. membranaceus (AMG1, AMG2, AMG3) in addition to a hydroalcoholic extract of A. membranaceus root (AST). Hypoglycemic effect, cholinesterase inhibition, and antioxidant activities were also evaluated. Thirty-one compounds, of which 19 polyphenols, and 12 saponins were identified. The extracts were also quantified by using a sensitive and selective Q-Trap system for their content in flavonoids and astragalosides, selecting astragaloside I and IV as chemical markers. From our results, AMG3 preparation (Axtragyl®) was the most abundant in terms of both specialized classes of metabolites, showing a fingerprint similar to that of A. membranaceus hydroalcoholic root extract. Interestingly, tested enzyme inhibition ability of flavonoids, daidzein (11) and formononetin (19) reported a higher α-glucosidase inhibition in comparison with that of acarbose used as positive control. The in silico study clarified the interactions among the molecules and the importance of having a free hydroxy group. Moreover, Axtragyl® was able to exert protective effects in Caco-2 cells treated with H2O2, confirming its ability as potential protective agent in intestinal injury.