桂花果实精油化学成分及体外抗氧化活性

采用水蒸气蒸馏法提取桂花果实精油,利用气相色谱-质谱联用技术分析其化学成分,并以面积归一化法测定各成分的相对含量;以维生素C或EDTA为阳性对照,以总还原力、金属离子的螯合作用、ABTS自由基和DPPH自由基的清除作用为指标评价桂花果实精油的体外抗氧化活性。研究结果表明,从桂花果实精油中共鉴定出44个化合物,占精油总量的89.12%,以酯类和酸类为主,分别占挥发油总量的47.28%和15.67%;挥发油主要成分有5-乙烯基-3-吡啶羧酸甲酯、对甲酰基苯甲酸甲酯、棕榈酸、1,21-二十二碳二烯、1,2-环氧十八烷。桂花果实精油具有良好的体外抗氧化活性,其总还原力、金属离子的螯合作用、ABTS自由基和DPPH自由基清除作用的ED50分别为147.63、41.25、33.51、50.94μL,且精油样品量与与各项抗氧化活性指标呈量效关系。

Chemical Constituents and Antioxidant Activities in vitro of Essential Oils from Osmanthus fragrans Fruits

The essential oils from Osmanthus fragrans fruits were extracted by water-steam distillation. Their chemical components were analyzed by gas chromatography-mass spectrometry, and the relative contents of the chemical components were determined with peak area normalization method. The antioxidant activities of essential oils in vitro were evaluated by total reducing power, metal chelating ability, and scavenging capacity against ABTS· and DPPH· with Vc or EDTA as the positive control. The results showed that 44 compounds, which occupied 89.12% of total constituents, were identified from the essential oils. The esters and acids were the dominant components in the essential oils, which occupied 47.28% and 15.67% of total constituents, respectively. The major compounds in the essential oils were 5-vinyl-3-pyridinecarboxylic acid methyl ester, methyl-4-formylbenzoate, palmitic acid, 1, 21-docosadiene and 1, 2-epoxyoctadecane. The essential oils exhibited significant antioxidant activities in vitro in a concentration-dependent fashion. The ED50 values of total reducing power, metal chelating ability, and scavenging capacity against ABTS· and DPPH· were 147.63, 41.25, 33.51, and 50.94 L, respectively.