Study of the antioxidant activity of the herb alfalfa sickle (Medicago falcata L.)

Objective: study of the antiradical and antioxidant activity of water, water-alcohol and alcohol extracts obtained from alfalfa sickle grass. Materials and methods. As an object of research of the antiradical and antioxidant activities of water, water-alcohol and alcohol extracts of alfalfa sickle, the grass of alfalfa sickle in the flowering stage, which was harvested in the Russian Federation in the Kursk region, was considered. The antioxidant activity was evaluated using a titrimetric method based on the result of the interaction of substances of a reducing nature that are present in extracts from alfalfa sickle grass and potassium permanganate used as a titrant. Antiradical activity was studied by spectrophotometric method based on the ability of extracts to inactivate DPPH (2,2-diphenyl-1-picrylhydrazyl). The content of phenolic compounds (direct spectrophotometry) in terms of chlorogenic acid and flavonoids (differential spectrophotometry) in terms of rutin was determined. Statistical analysis was used to process the data obtained as a result of experiments. Results. Processing of the results of data obtained during experiments to determine the level of antioxidant and antiradical activity for various concentrations of aqueous, water-alcohol and alcohol extractants from alfalfa sickle grass confirmed the presence of such effects for all types of extracts studied. Under experimental conditions with the use of 30% ethanol as an extractant, the maximum atioxidant activity was observed at the level of 58.55%. The use of 96% ethanol as an extractant showed similarly the maximum antioxidant activity, at the level of 56.63%, which is slightly less, but significantly exceeds other indicators. The content of flavonoids was fixed at the maximum level (0.51%) when using 30% ethanol. Under the same conditions, phenolic compounds were recorded with an index of 0.88%. The results obtained visualize a direct correlation between the level of antioxidant activity of the studied object of the herb Medicago falcata L. and the level of phenolic compounds in it. As for the use of 96% ethanol as an extractant, then in this extraction the content of hydroxycinnamic acids and flavonoids was less (0.14% and 0.04% respectively). Conclusion. The resulting data from a series of experiments on alfalfa sickle grass collected during the flowering phase confirm the prospects of medicinal plant raw materials Medicago falcata L. as a raw material having antioxidant activity, which makes it possible to consider it as a basis for continuing pharmacological research.