紫娇花挥发油成分的GC-MS分析及抗氧化能力测定

Analysis of chemical constituents by GC-MS and antioxidant capacity on essential oil from Tulbaghia violacea

采用水蒸气蒸馏法和固相微萃取法提取紫娇花不同部位的挥发油,结合气相色谱—质谱(GC-MS)与计算机检索联用技术对其化学成分进行分析和鉴定,用面积归一化法测定各组分的相对含量,并对该挥发油清除DPPH·自由基能力和总抗氧化能力进行了研究。结果表明:紫娇花挥发油具有成分及相对含量差异大、成分较简单、化合物种类以含硫化合物为主的特点。两种方法在紫娇花不同部位挥发油中共检测出了16种化学成分,以硫醚类和含硫烃类化合物为主,相对含量占总成分在80%以上,其中Disulfide,bis(2-sulfhydrylethyl)-含量最高,其余许多成分还具有一定的药用价值。两种方法所得到的挥发油化学成分具有一定的差异性,固相微萃取法对醇类、醛类和酯类物质提取效果较好,而水蒸气蒸馏法对含硫烃类、硫醚类和萜类的提取效果更好。实验条件下紫娇花挥发油清除DPPH·自由基的IC_(50)为17.46 mg·mL^(-1),清除率可达54.86%;紫娇花挥发油在相同条件下较L-抗坏血酸具有更强的总抗氧化力。该研究结果为进一步开发利用该植物资源提供了理论依据。

The essential oils of Tulbaghia violacea were obtained from different organs by steam distillation（SD）and solid phase microextraction（SPME）, which were analyzed by gaschromatography-mass spectrometry（GC-MS）, and the antioxidant activities of the essential oils were also investigated through the measurement of DPPH scavenging activity and total antioxidant capacity. The results showed that the compositions of the essential oils and their relative contents in different organs of T. violacea were significantly different, and totally sixteen compounds were indentified through two methods. Most of the ingredients in volatile oil were sulfide or sulfur compounds, accounting for more than 80% of the total composition, and the relative content of Disulfide, bis（2-sulfhydrylethyl）-was the highest. Some consitituents of the essential oils were valuable for pharmaceutical and for the production of spices. SPME was more effective for extraction of alcohols, aldehydes and esters, and SD was better for sulfur, sulfide and terpenoids extraction. IC50 for the essential oils on scavenging DPPH was 17.46 mg·mL^-1 and the scavenging rate against DPPH free radicals could reach 54.86%. The essential oils of T. violacea maintained higher antioxidant capacity than L-ascorbic acid. Our analysis on the compositions and their relative contents of essential oils in T. violacea provides the information for further utilization of this plant.