Chemical Composition of Three Different Fractions Obtained from the Leaves of Cassia occidentalis

Abstract

The chemical composition of three different fractions (dichloromethane, methanol, benzene) obtained from the leaves of Cassia occidentalis via column chromatography was studied. The aim of the research is to identify the fraction with the highest composition of insecticidal compounds which may be responsible for the insecticidal activity of the plant. The leaves were dried and milled into fine powder, they were first extracted by maceration in various solvents and thereafter the resulting extracts were purified using column chromatography. Fractions obtained from the columns were analysed using Gas Chromatography-Mass Spectrometry (GCMS). The GC-MS results revealed a total of nineteen compounds, prominent among them were hexadecane (45.10%) and heptadecane 8-methyl (13.61%) in the dichloromethane fraction. In the methanol fraction we had; pentadecanoic acid 14-methyl ester (15.50%) 9-octadecanoic acid (48.76%) and methyl stearate (27.6%). The benzene fraction contained; decane (4.70%); hexadecane (21.60%) and nonadecane (11.65%). The presence of decane, methyl stearate, hexadecane, 9-octadecanoic acic methyl ester, pentadecanoic acid -14 methyl ester, heptadecane 8-methyl and nonadecane in the plant extracts may be responsible for the insecticidal properties of Cassia occidentalis and should be of considerable interest to the development of novel natural insecticdes from this plant. All three fractions contained important insecticidal compounds, thus any of the solvents could be utilised in the formulation of potential biopesticides from C. occidentalis.