Plants non-nutritiously ingested by wild chimpanzee, and their bioactive constituents

作为发现具有生物活性天然产物的一种新途径，非洲野生黑猩猩非营养性食用植物已成为研究热点，其中一些植物具有明显的生物活性，如细胞毒性、酶活性抑制、免疫抑制和抗寄生虫活性。扁桃斑鸠菊的生物活性特别广泛和有效。在坦桑尼亚的马哈尔山国家公园进行的实地调查（M.霍夫曼）观察到，患病的黑猩猩将这种非常苦的植物用作药用。从该植物中分离得到倍半萜内酯类和甾体类化合物。苦味倍半萜内酯具有较强的细胞毒性和抗菌活性。所有的类固醇相关成分都是新的，一些分离的糖苷也尝起来很苦。使用这种植物的黑猩猩曾被认为患有与寄生虫有关的疾病。倍半萜内酯类化合物包括马鞭草苷和主要甾体相关成分斑鸠菊苷B_1及其天然苷元，具有明显的体外抗寄生虫活性。其中主要的倍半萜内酯类化合物马鞭草苷对感染尾蚴的小鼠有较强的毒性。木髓的使用似乎是马哈尔黑猩猩常用的部分。内酯在叶中含量丰富，树皮中含量较低。而在木髓中检测到的则微乎其微。而斑鸠菊苷B_1及其苷元含量在各部位均较高。基于这些，假设Mahale的黑猩猩通过摄取含有类固醇相关成分的植物的髓来控制寄生虫相关疾病。

As a new approach to discovering bioactive natural products, African plants non-nutritiously ingested by wild chimpanzees have been focused on. Several plants collected possessed significant bioactivities such as cytotoxicity, enzyme-activity inhibition, immuno-suppression, and antiparacitic activities. Bioactivities of Vernonia amygdalina were particularly broad and potent. Medicinal use of this highly bitter plant by sick chimpanzees had been observed by the field survey (M.Huffman) at the Mahale Mountains National Park, Tanzania. From this plant, sesquiterpene lactones and steroid related constituents were isolated. The bitter sesquiterpene lactones showed potent cytotoxic and also antibacterial activities. All of the steroid related constituents were new, and some of the isolated glucosides also tasted bitter. Chimpanzee used this plant had been thought to suffer from parasite-related diseases. The sesquiterpene lactones including vernodalin and major steroid related constituents, vernonioside B_1 and its natural aglycone showed significant antiparasitic activities in vitro. The major sesquiterpene lactone, vernodalin, was highly toxic to cercaria-infected mouse. The use of the pith seems to be the common part used by chimpanzees at Mahale. The lactone was shown to occur abundantly in the leaves, and slightly in the bark. While, it was negligibly detected in the pith. On the other hand, the levels of vernonioside B_1 and its aglycone were comparably high in all of the plant parts. Based on these, chimpanzees at Mahale were hypothesized to control parasite-related diseases by ingesting the pith of the plant containing steroid-related constituents.