title: Extraction and colorimetric determination of azadirachtin-related limonoids in neem seed kernel.
abstract: A colorimetric method was developed for the determination of total azadirachtin-related limonoids (AZRL) in neem seed kernel extracts. The method employed acidified vanillin solution in methanol for the colorization of the standard azadirachtin or neem seed kernel extracts in dichloromethane. Through the investigation of various factors influencing the sensitivity of detection, such as the concentration of vanillin, acid, and the time required for the formation of color, optimum conditions were selected to perform the assay. Under the optimum conditions, a good linearity was found between the absorbance at 577 nm and the concentration of standard azadirachtin solution in the range of 0.01-0.10 mg/mL. In addition, different extraction procedures were evaluated using the vanillin assay. The HPLC analysis of the extracts indicated that if the extractions were performed in methanol followed by partitioning in dichloromethane, approximately 50% of the value determined by the vanillin assay represents azadirachtin content.
authors.affiliation: Department of Agricultural and Biosystems Engineering and Department of Food Science, McGill University, 21111 Lakeshore, Ste Anne de Bellevue, Quebec, Canada H93 XV9.
authors.forename: J
authors.initials: J
authors.lastname: Dai
authors.forename: V A
authors.initials: VA
authors.lastname: Yaylayan
authors.forename: G S
authors.initials: GS
authors.lastname: Raghavan
authors.forename: J R
authors.initials: JR
authors.lastname: Parè
mesh_terms: D003124:Colorimetry / Q000379:methods; D036701:Limonins; D008968:Molecular Conformation; D010936:Plant Extracts / Q000737:chemistry; D012639:Seeds / Q000737:chemistry*; D014197:Trees; D014315:Triterpenes / Q000737:chemistry* / Q000302:isolation & purification*
chemical_list: D036701:Limonins; D010936:Plant Extracts; D014315:Triterpenes; C010329:azadirachtin