title: Variation of major limonoids in Azadirachta indica fruits at different ripening stages and toxicity against Aedes aegypti.
abstract: The azadirachtin, salannin, nimbin, deacetylnimbin, azadiradione and epoxyazadiradione contents were determined by HPLC in the fractions prepared from the kernel of neem fruits (Azadirachta indica) collected at different ripening stages. The fully mature fruit (yellow fruits) kernels contained the highest concentration of azadirachtin, nimbin and salannin, whereas the concentration of azadiradione (NC) and epoxyazadiradione (NL) was high in the unripe green berries. The toxicity of the fractions (KEA-1 to KEA-5) obtained from the kernels collected at successive intervals, as well as of the pure limonoids referred to above was evaluated against 3rd instar larvae of Aedes aegypti L. (wild strain). It was observed that the toxicity of these fractions increased with the maturity of the fruits. An interesting observation was that the toxicities of KEA-3 to KEA-5 are comparable and the concentration of all the major limonoids is optimum in KEA-3, which suggested that these exert a joint effect against Aedes aegypti.
authors.affiliation: H.E.J. Research Institute of Chemistry, International Center for Chemical & Biological Sciences, University of Karachi, Karachi-75270, Pakistan. bina@khi.comsats.net.pk
authors.forename: Bina Shaheen
authors.initials: BS
authors.lastname: Siddiqui
authors.forename: Syed Kashif
authors.initials: SK
authors.lastname: Ali
authors.forename: Syed Tariq
authors.initials: ST
authors.lastname: Ali
authors.forename: Syed Naeem ul Hassan
authors.initials: SN
authors.lastname: Naqvi
authors.forename: Rajput Muhammad
authors.initials: RM
authors.lastname: Tariq
mesh_terms: D000330:Aedes; D000818:Animals; D031601:Azadirachta / Q000737:chemistry* / Q000254:growth & development; D005591:Chemical Fractionation; D002851:Chromatography, High Pressure Liquid; D005638:Fruit / Q000737:chemistry* / Q000254:growth & development; D007306:Insecticides / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism; D007814:Larva; D007928:Lethal Dose 50; D036701:Limonins / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism
chemical_list: D007306:Insecticides; D036701:Limonins