摘要
Lepidium meyeniiWalp. （Maca）, a perennial herbaceous plant with narrow distdbution in the Andean region, was cultivated by local residents as early as 1600 B.C. It has high nutritional values and multiple medicinal effects. In recent years the plant source of Maca has been greatly scarce since Maca products are increasingly becoming popular in the world. This makes the study urgent on the identification and quality evaluation of Maca materials. In present work, four Mace samples of different origins or handlings and three other natural plants, including radish, odental ginseng and American ginseng, were investigated. Their essential oils （steam distillates） of the hypogeal parts were weighed and analyzed by GC/MS. Through comparison of the characteristics of their chromatograms, it was found that the essential oil of Maca had unique GC/MS behaviors, and the characteristic peaks produced by the major essential oil components （Phenylacetonitrile, Benzaldehyde, 3-Methoxyphenylacetonitrile, etc） were distinct. Furthermore, the chromatograms of several Maca samples showed a similar qualitative pattern except for some differences in the quantitative composition, and the percentage of total essential oils in the samples varied from 0.88 % to 1.59 %. These behaviors and technologies can be applied to the identification of Maca materials in the markets and be a supplement to assess the quality of Maca matedals.
玛咖(Lepidium meyenii Walp.(Maca))是南美安第斯山上分布较窄的一种多年生草本植物,早在公元前1600多年就被当地栽种。它具有很高的营养价值和多种药用价值,最近几年由于玛咖产品在国际上非常流行以致其资源紧缺,这就使得它的鉴别及其质量评价研究非常紧迫。我们对4种来源不同或者处理方式不同的玛咖以及与之容易混淆的3种植物(包括萝卜、人参和西洋参)进行了研究,提取其干根中的挥发油,称重并采用GC/MS进行分析。通过比较这些气相谱图,我们发现玛咖挥发油谱图具有独特特征,主要特征峰对应物质为苯乙腈、苯甲醛和3-甲氧基苯乙腈。而几种玛咖样品的图谱特征峰非常接近,仅在总含量上有0.88%到1.59%的波动。结果表明该技术可应用于玛咖材料的鉴定及其质量评价。
