Chemical Composition and Phytotoxic Activity of Lippia origanoides Essential Oil

Pepper rosemary (Lippia origanoides) is a medicinal plant rich in essential oil, containing as main phenolic compounds thymol or carvacrol, which have potential herbicidal activity. The aim of this study was to extract, characterise and test the phytotoxic activity of the essential oil (EO) obtained from pepper rosemary leaves, with a view to its potential use as a bioherbicide. The EO was obtained using the hydrodistillation method, with an extraction time of 3 hours and an average yield of 2.24%. Analysis of the EO by GC-MS identified thymol (79.37%), o-cymene (9.73%), caryophyllene (3.78%) and caryophyllene oxide (2.61%) as the main compounds. The in vitro biological assay evaluated the effect of the EO on the root growth of Lactuca sativa and Sorghum bicolor. At all tested concentrations, L. sativa seed germination was completely inhibited, while inhibition was total at 1% and 81% at 0.25% in S. bicolor seeds. It is concluded that the EO had a phytotoxic effect, likely due to the presence of thymol as the main constituent, and that pepper rosemary EO holds promise for use in formulations as a bioherbicide.

Funding FAPEMIG, CNPq and CAPES for financial support

Conflict of Interest

The authors declare no conflict of interest.

Publikationsverlauf

Artikel online veröffentlicht:
16. November 2023