一种新的无氧微波辅助方法提取中药挥发油

目的:将单向阀应用于微波提取中,使用真空泵抽出提取体系内的空气,制造无氧环境以提取植物中的挥发油,并考察其与常压微波提取法的优劣.方法:以莪术和薄荷为研究对象,分别采用单向阀-无氧微波提取法(check valve&nonoxygen microwave assisted extraction,CVNO-MAE)和微波无溶剂提取法(solvent free microwave extraction,SFME)提取莪术和薄荷挥发油,采用GC-MS技术对其进行化学成分分析.结果:CVNO-MAE和SFME所提取的莪术挥发油中总的烯类物质含量分别为48.22％,27.42％,含氧化合物质量分数分别为45.53％,62.38％.CVNO-MAE和SFME所提取的薄荷挥发油中总的烯类物质质量分数分别为13.53％,9.15％,含氧化合物质量分数分别为82.74％,89.57％.单向阀-无氧微波提取法提取的莪术和薄荷挥发油中含氧化合物含量皆低于微波无溶剂法.结论:真空微波提取法兼备了微波加热的快速及真空条件下无氧萃取的优点,单向阀的使用,有效地阻止了挥发油易氧化成分的氧化,是一种可行的无氧微波提取方法.

Check valve and non-oxygen microwave assisted extraction of Chinese herbs: study of a novel technique for extraction of essential oils

Objective : A novel green extraction technique of check valve & non-oxygen microwave assisted extraction (CVNO-MAE) for essential oils extraction was established. CVNO-MAE is a combination of microwave heating, vacuum pump and check valve, performed at anaerobic environment without added any solvent or water. Method : CVNO-MAE has been compared with a conventional technique, solvent free microwave extraction (SFME), for the extraction of essential oils from two Chinese herbs: Curcuma phaeocaulis and Mentha haplocalyx . Result : GC-MS analyses of the oils revealed the presence of 36 and 37 compounds in the essential oils of C. phaeocaulis and M. haplocalyx, respectively. There was an obvious difference in the quality of essential oils obtained by the two kinds of extraction methods. The CVNO-MAE method yielded an essential oil of C. phaeocaulis with lower amounts of oxygenated compounds (45. 53%) than SFME (62. 38%). Higher amounts of oxygenated compounds (89. 57%) were present in the M. haplocalyx essential oil of SFME in comparison with CVNO-MAE (82. 74%). Conclusion : CVNO-MAE is a fast low temperature extraction method carried in under pressure, appears as a good alternative for the extraction of essential oils from Chinese herbs and a green technology.