胡椒果与叶都具有抗氧化活性，而叶还具有抗动脉粥样硬化功能，但胡椒叶的活性因子并不明确，另摘叶可以提高胡椒产量，为给胡椒叶开发利用提供理论依据，本文用氧自由基清除能力（ORAC）方法评价了胡椒叶的抗氧化活性，结果表明胡椒叶ORAC值为3639.05 μmol TE/g，高于胡椒果（胡椒鲜果、白胡椒和黑胡椒）；通过系统溶剂提取法，确定了胡椒叶的乙醇提取物的ORAC值最高；以ORAC检测方法作为分离鉴定抗氧化活性物质的追踪方法，对胡椒叶乙醇提取物依次萃取和采用硅胶层析、凝胶层析、反相层析、薄层层析及HPLC等方法分离纯化得到活性目标物，通过核磁共振和质谱等手段鉴定与表征，首次从胡椒中分离得到两种具有较高抗氧化活性的扁柏脂素和野漆树苷，其ORAC值分别为16070 μmol TE/g和 10823 μmol TE/g。

The leaves and fruit of Piper nigrum Linnaeus (black pepper)exhibit antioxidant activities; the leaves also possess anti-atherosclerotic properties, and the removal of black pepper leaves can increase the yield of pepper fruits. However, the active components in the leaves of Piper nigrum L. were not clear. In order to provide a theoretical basis for the exploitation of Piper nigrum leaves, the antioxidant activity was analyzed by oxygen radical absorbance capacity (ORAC). The results indicated that the ORAC value of the Piper nigrum leaves was 3639.05 μmol TE/g, which was greater than that of the Piper nigrum fruits (fresh, black, and white). Through serial solvent extractions, the ethanol extract of Piper nigrum leaves was determined to have the highest ORAC value. Using the ORAC detection method as the tracing method for the separation and identification of antioxidative components, the active target compounds were isolated after successive extractions of the ethanol extracts of Piper nigrum leaves, followed by silica gel chromatography (Sephadex LH-20 resin), gel-filtration chromatography, reversed-phase chromatography, thin-layer chromatography, and high-performance liquid chromatography. The identification and characterization experiments carried out using nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry (MS) confirmed that hinokinin and rhoifolin-two active ingredients with high antioxidant activities-were separated from Piper nigrum leaves, and their ORAC values were 16070 μmol TE/g and 10823 μmol TE/g, respectively.

国家科技支撑计划项目（2012BAD03）