野牡丹提取液的抗氧化活性研究

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•）和铁离子还原/抗氧化能力（FRAP）测定法，测定其抗氧化活性，并将其与芦丁和维生素C（Vc）的抗氧化能力进行比较研究。结果 野牡丹提取液具有较强的抗氧化能力，对DPPH自由基有较好的清除率，半数清除浓度（IC₅₀）为23 μg/mL；对Fe³⁺也具有较好的还原能力，0.5 mol/L FeSO₄当量对应野牡丹提取液质量浓度为55 μg/mL。结论 野牡丹的抗氧化能力与芦丁相近，低于Vc。野牡丹的抗氧化活性在一定浓度范围内与黄酮的含量有较好的相关性。

Study on the antioxidant activity of extract from Melastoma candidum

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.