Study on the Functional Composition and Its Antioxidant Activity of the Fruits of Rubus crategefolius Bunge.

Rubus crategefolius Bunge. is used as traditional medicinal plant, and abound in natural resources. In the present study, the extract of dry fruits of R. crategefolius. Bunge was prepared by water extraction and alcohol precipitation method, alcohol extraction method, and heating reflux and other methods, and its chemical constituents and antioxidant activities were investigated. The contents of total flavonoids, total saponins, total phenolic acids, total amino acids and total polysaccharides were determined by UV spectrophotometry. The scavenging abilities of ethanol extract of R. crategefolius Bunge. fruits on DPPH free radical, ABTS free radical and superoxide anion free radical were determined. The contents of total flavonoids, total saponins, total phenolic acids, total polysaccharides and total amino acids were 1.31%, 0.96%, 0.44%, 0.55% and 1.39%, respectively. The IC₅₀ values of DPPH, ABTS, superoxide anion and hydroxyl radical scavenging rate were 0.087, 0.26, 2.23, and 2.12 mg/mL respectively. In conclusion, fruit extract of R. crategefolius Bunge. contained flavonoids, saponins, phenolic acids, amino acids, polysaccharides, and had good antioxidant activity.