Bioassay Guided Isolation and Structural Elucidation of Anti-Feeding Compounds against Chilo Partellus (Swinhoe) In Fruits of Elaeodendron Buchananii L

Tsanuo, Muniru Khamisi (1992) Bioassay Guided Isolation and Structural Elucidation of Anti-Feeding Compounds against Chilo Partellus (Swinhoe) In Fruits of Elaeodendron Buchananii L. Masters thesis, Kenyatta University.

PDF (Bioassay Guided Isolation and Structural Elucidation of Anti-Feeding Compounds against Chilo Partellus (Swinhoe) In Fruits of Elaeodendron Buchananii L) Bioassay guided isolation and structural elucidation of anti-feeding compounds against chilo partellus (swinhoe) in fruits elae odendron buchananii l..pdf - Accepted Version Restricted to Repository staff only Download (60MB)

Abstract

This thesis describes a feeding deterrent bioassay guided chromatographic isolation of compounds found in the fruits of Elaeodendron buc nerien i i Loes , a Kenyan f olk medicinal plant that is used to cure diarrhoea. syphillis. wounds and stomachache. and their structural elucidation. Unripe fruits of E. buchananii were extracted with methanol. n - hexane. and chloroform successively. Feeding bioassay of the three extracts on third instar larvae of the stem borer Chilo partellu5 Swinhoe demonstrated that only the chloroform extract was active (51.6% deterrence at 100 }Jg/disc). The chloroform extract was then chromatographed on silica gel using gradient elution of a mixture of acetone in petroleum ether (Bp 40-600C) to give three active fractions. V.VI and VII that gave percentage anti-feeding activities of 88.5. 77.8 and 60.9 respectively at 100pg/disc. Further chromatographic work on fraction V led to the isolation of 1a, 2a, 6β-triacetoxy-9β. 15a-dibenzoyloxy-β-dihydroagarofuran I' (1). a new compound. and β-sitosterol (2). The feeding deterrences of cornpound(1) and (2) at 100 J.lg/discwas 64.9% and 31.7% respectively. Chromatographic purification of fraction VI led to the isolation of a third compound that demonstrated feeding deterrence of 98.0% at 100pg/disc. Some functional groups present in it were determined. The structures of (1) and (2) were determined by spectral data analysis and correlation with published data. , The characteristic mass spectral fragmentation patterns and molecular ions. 13nmr and 1Hnmr chemical shifts and their integration led to the formulations of the molecular structures. The functional groups were infered from IR. UV and Distortionless Enhancement by Polirization Transfer (DEPT) spectra. Correlation Spectoscopy (COSY) spectra was useful in assighning the stereochemistry of the structures.

Item Type:	Thesis (Masters)
Subjects:	Q Science > QD Chemistry
Divisions:	Africana
Depositing User:	Geoffrey Obatsa
Date Deposited:	13 Sep 2017 06:23
Last Modified:	13 Sep 2017 06:23
URI:	http://thesisbank.jhia.ac.ke/id/eprint/2081

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