Antifungal Activity of the Essential Oil of Basil (Ocimum basilicum)

The antifungal and fungicidal effects of two chemotypes of basil (Ocimum basilicum) oil and its major individual components were studied in a series of in vitro and in vivo experiments. Mycelial growth of the plant pathogenic fungus Botrytis fabae was reduced significantly by both the methyl chavicol chemotype oil and the linalol chemotype oil, and the major individual components of the oils all reduced fungal growth, with methyl chavicol, linalol, eugenol and eucalyptol reducing growth significantly. Combining the pure oil components in the same proportions as found in the whole oil led to very similar reductions in fungal growth, suggesting that the antifungal effects of the whole oils were due primarily to the major components. When the fungus was exposed to the oils in liquid culture, growth was reduced by concentrations considerably smaller than those used in the Petri dish studies. Botrytis fabae and the rust fungus Uromyces fabae were also controlled in vivo, with the whole oils of both chemotypes, as well as pure methyl chavicol and linalol, reducing infection of broad bean leaves significantly. Most effective control of fungal infection was achieved if the treatments were applied 3 h postinoculation.