A study of flavonoids, hydroxycinnamic acids and antioxidant activity of Astragalus cicer L. herb harvested in the Saratov Region

Introduction. Astragalus cicer L. is a perennial herbaceous plant from the Fabaceae family, used in folk medicine as a hypotensive, diuretic, and sedative, for the treatment of cardiovascular diseases and digestive disorders. Earlier studies isolated compounds related to flavonoids from the herb. Phytochemical studies of Astragalus cicer are relevant due to its pharmacological properties. Aim. To study flavonoids, hydroxycinnamic acids and antioxidant activity of Astragalus cicer L. herb harvested in the Saratov Region. Materials and methods. The study involved Astragalus cicer L., a herb harvested in 2023 in the Saratov Region (Kazachka village, Kalininsky district) and air-dried. Extraction of the raw material was performed with 70 % ethyl alcohol at a raw material-to-extractant ratio of 1 : 10 for qualitative phytochemical analysis of phenolic compounds (including flavonoids and hydroxycinnamic acids). Quantitative flavonoid content was determined by differential spectrophotometry in terms of rutin, and hydroxycinnamic acids were determined by direct and differential spectrophotometry in terms of caffeic acid. Antioxidant activity was assessed by permanganometric titration using a patented method (Maksimova, 2000), expressing the results as rutin and quercetin equivalents. Results and discussion. Phytochemical analysis revealed flavonoids and other phenolic compounds in the aqueous-alcoholic extract of Astragalus cicer . Direct spectrophotometry for hydroxycinnamic acid content in Astragalus cicer yielded overestimated results (1.75 ± 0.01 %) due to low wavelength selectivity. Selective differential spectrophotometry with Arnov's reagent revealed hydroxycinnamic acid content of 0.99 ± 0.01 % as caffeic acid. Flavonoid content as rutin was 1.42 ± 0.02 %. Pronounced antioxidant activity was found: 22.83 ± 0.68 mg/g as rutin and 15.56 ± 0.38 mg/g as quercetin. Conclusion. A phytochemical study of Astragalus cicer herb harvested in the Saratov Region revealed a high content of hydroxycinnamic acids and flavonoids, as well as pronounced antioxidant activity in a 70 % ethanol extract.