Study on Biological Activities of Xanthone Compounds from Polygala Crotalarioides

Ethanol reflux was used to extract xanthone compounds from Polygala crotalarioides, and AB−8 macroporous adsorption resin was used to purify xanthones. The inhibitory activity of xanthine oxidase by the crude ethanol extract and the xanthone compounds after purification was determined, DPPH, ABTS^+•, O₂^•− and •OH clearance were used to study their antioxidant activities, the antibacterial activities of 5 kinds of bacteria were studied by 96-well plate method, the growth rate method was used to determine the inhibitory activities of 5 species of fungi. The results showed that the IC₅₀ of the crude ethanol extract and the xanthone compounds after purification were 966 and 348.7 μg/mL, respectively. After purification, the inhibitory activity of xanthine oxidase was increased by 2.77 times. The IC₅₀ of DPPH, ABTS^+•, O₂^•− and •OH radical scavenging activities in ethanol extract were 283.85, 226.37, 304.36 and 236.82 μg/mL, respectively. After purification, the IC₅₀ of DPPH, ABTS^+•, O₂^•− and •OH radical scavenging capacity were 147.81, 104.34, 166.92 and 119 μg/mL, respectively. In terms of inhibitory activity against bacteria, it showed the strongest inhibitory effect on Proteus vulgaris. The second was the inhibition of Staphylococcus aureus, Pseudomanas aeruginosa and Salmonella enterica subsp. enteric. And the inhibition of Escherichia coli was the weakest. In terms of inhibitory activity against fungi, the EC₅₀ of Coriolus versicolor, Fusarium solani, Fusarium graminearum, Fusarium oxysporum and Alternaria brassicicola were 0.237 9, 0.507 4, 1.184 4, 0.899 1 and 0.368 7 mg/ml, respectively.