Anti-termite Activities of Extracts from Euphorbia tithymaloides and Euphorbia tithymaloide variegatus

Abstract

The objective of this work was to investigate the anti-termite properties of solvent extracts of two Euphorbia plant species, Euphorbia tithymaloides and Euphorbia tithymaloides “variegatus”. Termiticidal activity of stem barks and leaf extracts were analysed by using anti-termite activity tests. All crude extracts obtained by petroleum ether and ethyl acetate exhibited 100% repellency activities at a concentration of 36 mg mL^-1. Average repellency time decreased as the concentration of crude extracts were increased. Contact bioassay tests revealed that crude extracts from stem barks are more potent than extracts from leaves; and non-polar solvents gave crude extracts which are more effective that those extracted by polar solvents. Crude extracts obtained by petroleum ether from stem barks of both E. tithymaloides and E. tithymaloides “variegatus” plants species gave dissimilar peaks in GC-MS chromatograms, except two peaks, which correspond to the compounds: 1-heptadecene and n-hexadecanoic acid. Crude extract from E. tithymaloides gave a prominent peak corresponding to the compound tetracontane as the principal constituent (73.7%) of the extract. Since this peak is absent in crude extracts from E. tithymaloides “variegatus” stem barks, its presence in crude extracts from E. tithymaloides stem barks can be attributed to its high termite lethality assay results. In general, from the results obtained from this work, it could be concluded that the Euphorbia species are potential sources of botanical pesticides against termites.