Allelopathic effects of volatile compounds of essential oil from Ravensara aromatica Sonnerat chemotypes

The chemical compositions of three chemotypes of Ravensara aromatica Sonn. (Lauraceae) leaf essential oils (EOs) was determined by GC and GC/MS. One chemotype rich in aromatic components (methyl chavicol) and two chemotypes rich in terpenic components (limonene and sabinene as main compounds, respectively) were identified. The three chemotypes were inhibitory to germination and phytotoxic to seedlings of rice (Oryza sativa), garden cress (Lepidium sativum) and greengram (Vigna radiata). Germination inhibition and phytotoxicity varied significantly among the chemotypes. The limonene chemotype was least herbicidal and the sabinene chemotype was most toxic to rice and cress seedlings. The chemotype rich in methyl chavicol was most inhibitory to germination of greengram and rice. Rice proved most resistant to allelopathic effects of test essential oils than two dicotyledons (Green gram, garden cress). The potential use of essential oils of R. aromatica as a bioherbicide is discussed. (Résumé d'auteur