INSECTICIDAL COMPOUND: ISOLATION AND CHARACTERIZATION OF STEROIDAL SAPONIN
The objective of this study is isolation and characterization of the steroidal Saponin; Stigma-4-en-3-o-β-DGalactopyranoside from the seeds of Annona squamosa. The ethyl acetate soluble part was obtained from concentrated ethanolic extract of Annona squamosa. This extract showed the presence of two compounds when subjected to TLC examination on Si-gel plates using chloroform: ethyl acetate (1:2) as solvent an iodine vapours as visualizing agent. Therefore the ethyl acetate soluble part was concentrated to a viscous mass, and both the compounds were separated by subjecting this viscous ethyl acetate mass to column chromatography over Si-gel and eluating from chloroform: methanol in different proportions. The fractions from chloroform: methanol in different proportions. The fractions from chloroform: methanol (7:3) which had same Rf values, were then mixed and studied, while the eluates from chloroform: methanol (2:3) could not be further studied for want of material. (RS—1) was found to be soluble in water, readily soluble in methanol and pyridine and insoluble in benzene (RS-1) also responded to all the characteristics color reactions for steroids confirming it to be a steroidal Saponin. Spectral analysis of the sample also showed the characteristic peaks of steroidal Saponin. The characterization on the basis of the spectral data obtained, clearly depicts the compound as Stigma-4-en-3-O-β-D-Galactopyranoside (Steroidal Saponin)