Chemical composition, larvicidal and antibacterial activities of some leaves of the Cameroonian’s flora

Recent studies have demonstrated the resistance of target pests to certain chemical insecticides. Environmental pollution is one result of the use of these chemical insecticides. The objective of this study was to determine larvicidal and antibacterial properties of the essential oil extracted from plants (Curcuma longa, Petroselinum crispum and Apium graveolens) by hydrodistillation. These plants were selected because of their utilisation, for instance, as tea. Chemical composition was analyzed using gas chromatography (GC) and GC coupled with mass spectrometry (GC-MS). Larvicidal efficacy was assessed following guidelines established by the World Health Organization (WHO). C. longa yielded the highest extraction efficiency at 0.9%. All these samples are rich in monoterpenes (C. longa: 87.90%; P. crispum: 97.80%; A. graveolens: 88.08 %; M. piperita: 94.94%). In C. longa extract, Δ3-carène (37.40%) was the main compound. In the Apiaceae, 1,8-cinéole was the major component (P. crispum: 63.97% and A. graveolens: 63.33%). The larvicidal tests showed that C. longa and P. crispum exhibited the highest larvicidal activity on Anopheles gambiae s.l. larvae. The immature stages were most susceptible. In addition, A. graveolens and P. crispum exhibited excellent antibacterial properties. Bacillus subtilis was the most sensible (DI=12mm). C. longa and P. crispum essential oils can be used as bio-insecticide and A. graveolens as a natural antibiotic.