Chemical compositions and antioxidant activity of Heracleum persicum essential oil

ABSTRACT In this study essential oil of the aerial parts of Heracleum persicum a spice widely used in Iran was isolated by conventional hydrodistillation (HD) and microwave-assisted hydrodistillation (MAHD) techniques. The extraction yield was determined and the chemical compositions of essential oils were identified by the application of gas chromatography/mass spectrometry (GC/MS). The antioxidant activity was determined by two different methods: 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging and oven test methods. Although the main compounds of essential oils by the both extraction methods were similar, the essential oil extracted by HD with lower extraction efficiency showed more diverse compounds. The evaluation of antioxidant activity of the essential oil measured by delay in sunflower oil oxidation indicated that the antioxidant activity was dependent on the concentration which increased when higher concentrations of the essential oils were applied. The results of DPPH radical assay also indicated that the percentage of inhibition increased with increasing of essential oil concentration and IC50 value for essential oil extracted by MAHD method was obtained 1.25 mg/mL. Therefore the Heracleum persicum essential oil might be recommended for use as a flavoring agent and a source of natural antioxidants in functional foods, formulation of the supplements and in medicinal due to numerous pharmacological activities.摘要 本研究以伊朗广泛使用的香料植物波斯独活（Heracleum persicum）的地上部分为原料，分别采用传统水蒸馏法（hydrodistillation, HD）与微波辅助水蒸馏法（microwave-assisted hydrodistillation, MAHD）提取其精油。测定了两种方法的精油得率，并通过气相色谱-质谱联用法（gas chromatography/mass spectrometry, GC/MS）对精油的化学成分进行鉴定。采用两种不同方法评估精油的抗氧化活性：1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl, DPPH）自由基清除法与烘箱氧化试验法。尽管两种提取方法所得精油的主要化合物种类相似，但得率较低的传统水蒸馏法提取的精油化学成分更为多样。通过向日葵油脂氧化延缓试验评估精油抗氧化活性的结果显示，其抗氧化活性与浓度呈正相关，即精油浓度越高，抗氧化效果越强。DPPH自由基清除试验的结果同样表明，抑制率随精油浓度升高而上升，微波辅助水蒸馏法提取的精油的半数抑制浓度（IC50）为1.25 mg/mL。鉴于其多样的药理活性，波斯独活精油可被推荐用作调味剂、天然抗氧化剂来源，应用于功能性食品、补充剂配方以及医药领域。