Ring A-seco mosquito larvicidal limonoids from Turraea wakefieldii

Five novel limonoids, 1-5, were isolated from the root bark of Turraea wakwfieldii and were characterized as tecleaninoid derivatives. This is the first report of the natural occurrence of tecleanin-type limonoids with a five-membered-ring A-seco structure for which we propose the name neotecleanins. The relative stereochemical structures Of Compounds 1-5 were established on the basis of NMR spectroscopy. The absolute stercochemical structure of 5 was confirmed by X-ray diffraction methods. In mosquito larvicidal assays, compounds 1, 2 and 4 showed dose-dependent larvicidal activity against larvae of Anopheles gambiae s.s. (C) 2003 Elsevier Ltd. All rights reserved.