目的 研究野牡丹提取液的抗氧化活性。方法 采用二苯代苦味肼基自由基（DPPH•）和鐵離子還原/抗氧化能力（FRAP）測定法，測定其抗氧化活性，并將其與蘆丁和維生素C（Vc）的抗氧化能力進(jìn)行比較研究。結(jié)果 野牡丹提取液具有較強(qiáng)的抗氧化能力，對DPPH自由基有較好的清除率，半數(shù)清除濃度（IC₅₀）為23 μg/mL；對Fe³⁺也具有較好的還原能力，0.5 mol/L FeSO₄當(dāng)量對應(yīng)野牡丹提取液質(zhì)量濃度為55 μg/mL。結(jié)論 野牡丹的抗氧化能力與蘆丁相近，低于Vc。野牡丹的抗氧化活性在一定濃度范圍內(nèi)與黃酮的含量有較好的相關(guān)性。

Objective To study the antioxidant activity of the extract from Melastoma candidum. Methods The antioxidant activity was observed and comparied with the antioxidant capacities of Vc and rutin by two methods, namely, 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and ferric reducing antioxidant power (FRAP) assay. Results The extract from M. candidum had the high antioxidant activity, which was manifested in DPPH free radical scavenging activity and the ability to reduce ferric ions. The IC₅₀ (50% the initial DPPH·concentration) of the extract from M. candidum was 0.023 mg/mL. The concentration of 0.5 mol/L ferrous sulfate had the same reducing ability with the extract from M. candidum was 0.055 mg/mL. Conclusion M. candidum has the similar antioxidant activity with rutin, but less than Vc. The antioxidant capacity of M. candidum has closely correlated with the concentration of flavonoids in a certain range.