宁夏不同类型草地百里香挥发性有机物的组成及其差异

Analysis on composition and difference of volatile organic compounds in thyme from different types of grassland in Ningxia

为研究处于宁夏不同气候条件草地百里香(Thymus monogolicus)不同部位的鲜、干材料挥发性有机物的组成及其差异,本研究于10月上旬分别在宁夏盐池麻黄山荒漠草地、固原云雾山典型草地与海原南华山草甸草地采集百里香地上植株,采用气相色谱-质谱联用技术(GC-MS)对其挥发性成分进行分离鉴定,利用面积归一化法确定各成分的相对含量。结果表明:3种类型草地百里香不同部位鲜、干样品中共检测出339种挥发性有机物,分属于烃类(125种)、醇类(70种)、酯类(29种)和其他类化合物(115种)。对于挥发性成分种类数量,草甸草地百里香挥发性有机物数量大于荒漠草地和典型草地,鲜样多于干样。挥发性成分中烃类物质相对含量最多,主要以萜烯类物质对伞花烃和γ-萜品烯为主,分别为14.24%~42.24%和3.30%~37.35%,对伞花烃在草甸草地的相对含量多于典型草地和荒漠草地,在嫩茎中多于木质化茎和叶片,而在鲜样与干样中的相对含量相当。酚类、醇类及其他挥发性有机物主要有香芹酚、桉树醇、芳樟醇及2-异丙基-4-甲基苯甲醚,香芹酚的相对含量在荒漠草地最高,达20.61%,桉树醇和芳樟醇在草甸草地的相对含量最高,分别为9.68%和12.99%。综上,采样地气候条件、样品处理及不同部位对百里香释放的挥发性物质种类和含量具有一定影响,干燥样仍能较好地保持百里香的主要成分组成,研究结果可为宁夏野生百里香资源的开发应用提供科学依据。

To study the composition and differences of volatile organic compounds(VOCs)in fresh and dry materials of Thymus monogolicus from grasslands under different climatic conditions of Ningxia.The aboveground samples of T.monogolicus were collected from the desert grassland of Mahuang Mountain in Yanchi,the typical grassland of Yunwu Mountain in Guyuan,and the meadow grassland of Nanhua Mountain in Haiyuan in early October.The volatile components were separated and identified using gas chromatography-mass spectrometry(GC-MS),and the relative content of each component was determined using the area normalization method.The results showed that 339 VOCs were detected in fresh and dry samples of different parts of thyme,which belonged to hydrocarbons(125 types),alcohols(70 types),esters(29 types),and other compounds(115 types).The amount of VOCs types in thyme from meadow grassland was greater than that from desert grassland and typical grassland,and fresh samples had more VOCs than dry samples.The relative content of hydrocarbons in volatile components was the highest,mainly including terpenoids p-cymene andγ-terpinene,which were 14.24%~42.24% and 3.30%~37.35%,respectively.The relative content of p-cymene from meadow grassland was higher than that from typical grassland and desert grassland,which in tender stems was higher than that in lignified stems and leaves,which in fresh samples and dry samples was simila.Phenols,alcohols and other volatile organic compounds mainly included carvacrol,eucalyptol,linalool and 2-isopropyl-4-methylanisole.The relative content of carvacrol from desert grassland was the highest,reaching 20.61%.The relative content of eucalyptol and linalool of thyme from meadow grassland was the highest,reaching 9.68% and 12.99%,respectively.In summary,climatic conditions,sample processing,and different organs have an impact on the types and contents of VOCs in thyme,whereas dry samples can still maintain the main components of thyme.These results provide a scientific basis for the development and application of wild thyme resources in Ningxia.