Evaluation of Anti-MRSA and Xanthine Oxidase Inhibition Activities of Phenolic Constituents from Plumula nelumbinis.

Isolation of metabolites from Plumula nelumbinis led to the discovery of eleven compounds, including six flavonoids and five phenolderivatives. Their structures have been determined on the basis of chemical and spectroscopic data. Most of them, such as compounds 1, 4, 6, 8, and 10, have shown inhibitory activity against hospital-acquired methicillin-resistant Staphylococcus aureus (HA-MRSA). MICs of compound 8 against SA-200195 and SA-300150 were 2 μg/mL and 8 μg/mL, respectively. And the antioxidant activity of isolated compounds was determined by checking the scavenging activity against three different radicals: 2,2-diphenyl-1-picrydrazyl (DPPH) radical, hydroxyl radical (OH∙), and superoxide anion (O2∙-), as well as xanthine oxidase inhibition. All flavonoids showed strong antioxidant activity. And compound 6 displayed the highest inhibitory effect against xanthine oxidase with IC50 value of 8.2 μg/mL. [ABSTRACT FROM AUTHOR]