Phytochemical Analysis of Tephrosia vogelii across East Africa Reveals Three Chemotypes that Influence Its Use as a Pesticidal Plant
Phytochemical Analysis of Tephrosia vogelii across East Africa Reveals Three Chemotypes that Influence Its Use as a Pesticidal Plant
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DOI：
10.3390/plants8120597
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发表时间：
2019-12-01
期刊：
影响因子：
4.5
通讯作者：
Stevenson, Philip C.
中科院分区：
文献类型：
--
作者：
Mkindi, Angela G.;Tembo, Yolice;Stevenson, Philip C.
非洲山毛豆是一种植物物种，其化学特征是存在昆虫毒性类鱼藤酮，并在非洲广泛用作植物杀虫剂。进行了植物化学分析，以确定东非三个国家（坦桑尼亚，肯尼亚和马拉维）的生物活性成分的存在和丰度。本文分析了毛白杨叶部分的甲醇提取物。Vogelii揭示了两种不同化学型的存在，其中一种化学型中存在类鱼藤素，另一种化学型中存在对昆虫没有生物活性的黄烷酮和黄酮。具体地，化学型1含有鱼藤素作为主要的类鱼藤素沿着有茶黄素，以及鱼藤酮作为次要组分，而这些化合物不存在于化学型2中，其含有先前报道的黄烷酮和黄酮，包括obovatin-3-O-甲基醚。化学型3含有化学型1和2的化学特征的组合，表明化学杂交。被鉴定为化学型1的植物样品显示出跨季节和海拔的化学一致性，除了在坦桑尼亚的样品中观察到显著差异的雨季。由于农民无法确定现有材料的化学含量，因此在推广该物种进行害虫管理时必须小心，而不必首先确定功效。虽然植物化学分析是控制农药植物质量的一个重要工具，但在没有分析设施的情况下，可以开发简单的生物测定法，使推广人员和农民能够确定其植物的功效，并确保只采用有效材料。
Tephrosia vogelii is a plant species chemically characterized by the presence of entomotoxic rotenoids and used widely across Africa as a botanical pesticide. Phytochemical analysis was conducted to establish the presence and abundance of the bioactive principles in this species across three countries in East Africa: Tanzania, Kenya, and Malawi. Analysis of methanolic extracts of foliar parts of T. vogelii revealed the occurrence of two distinct chemotypes that were separated by the presence of rotenoids in one, and flavanones and flavones that are not bioactive against insects on the other. Specifically, chemotype 1 contained deguelin as the major rotenoid along with tephrosin, and rotenone as a minor component, while these compounds were absent from chemotype 2, which contained previously reported flavanones and flavones including obovatin-3-O-methylether. Chemotype 3 contained a combination of the chemical profiles of both chemotype 1 and 2 suggesting a chemical hybrid. Plant samples identified as chemotype 1 showed chemical consistency across seasons and altitudes, except in the wet season where a significant difference was observed for samples in Tanzania. Since farmers are unable to determine the chemical content of material available care must be taken in promoting this species for pest management without first establishing efficacy. While phytochemical analysis serves as an important tool for quality control of pesticidal plants, where analytical facilities are not available simple bioassays could be developed to enable extension staff and farmers to determine the efficacy of their plants and ensure only effective materials are adopted.