Siddiqui S, Faizi S, Siddiqui B S
H.E.J. Research Institute of Chemistry, University of Karachi, Pakistan.
J Nat Prod. 1992 Mar;55(3):303-10. doi: 10.1021/np50081a005.
Mahmoodin [1], a new limonoid, has been isolated from Azadirachta indica (neem) oil, along with seven known tetranortriterpenoids, azadirone, epoxyazadiradione, nimbin, gedunin, azadiradione, deacetylnimbin, and 17-hydroxyazadiradione. A new protolimonoid, naheedin [3], has been obtained from the neem fruits along with azadirachtol. Their structures have been elucidated through chemical and spectral analyses including 2D nmr studies. The absolute configuration of 1 was established by comparison of its cd spectrum with those of the known tetranortriterpenoids. Mahmoodin showed significant antibacterial activity against various Gram-positive and Gram-negative organisms. Four hydrocarbons, icosane, docosane, 2-methyltricosane, and docosene, have also been identified by gc-ms of the EtOH extract of the fruit coats. Only docosane has earlier been reported from neem, while the remaining three are unreported from this plant.
马哈穆迪宁[1]是一种新的柠檬苦素，已从印楝（印度楝树）油中分离出来，同时还分离出了七种已知的四降三萜类化合物，即印楝酮、环氧印楝二酮、印楝素、格杜宁、印楝二酮、去乙酰印楝素和17-羟基印楝二酮。一种新的原柠檬苦素，纳赫丁[3]，已与印楝醇一起从印楝果实中获得。它们的结构已通过包括二维核磁共振研究在内的化学和光谱分析得以阐明。通过将其圆二色谱与已知的四降三萜类化合物的圆二色谱进行比较，确定了1的绝对构型。马哈穆迪宁对多种革兰氏阳性和革兰氏阴性菌显示出显著的抗菌活性。通过对果皮乙醇提取物进行气相色谱-质谱分析，还鉴定出了四种碳氢化合物，即二十烷、二十二烷、2-甲基二十三烷和二十二碳烯。之前仅从印楝中报道过二十二烷，而其余三种在此植物中未见报道。
