Phytochemical and allelopathic activity study of the n-hexane extract from the foliage of Lantana trifolia L.

Abstract

Recently the phytochemical study of the plants guided by bioassays is very important, because the isolated metabolites of that can be used as natural herbicide sources. Weeds cause several losses on the crop production systems in the world and these losses are bigger in less developed countries. The subject of the research was the allelopathic study from leaves of Lantana trifolia L., belonging Verbenaceae family. Besides, to isolate and to characterize possible allelopathic agents from n-hexane extract from leaves. Allelopathic activity of this extract at 1 % was studied on laboratory conditions in vitro, vigour sign and growth reduction of root and coleoptile on cucumber and wheat plants were tested. On phytochemical study of n-hexane extract, triterpenes and steroids were detected and by chromatographic techniques (exclusion column chromatography, silice gel and preparative thin chromatography) two compounds were isolated. By physical properties and spectroscopy data (IR, Mass Spectroscopy, NMR1H and 13C) they were described. The n-hexane extract inhibits plants growth on study, showing root and coleoptile’s growth reduction on both plants and from this extract were identified the phytosterol ∆5-estigmastan-β-3-ol (β–sitosterol) and the lineal diterpene 7,11,15-trimethyl-3methylen-hexadecan-1,2-diol, this one is described for the first time in the genus Lantana.