Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: 10/1/2002
Publication Date: 10/18/2002
Citation: Kyle, S.K., Svoboda, K.P., Walters, D.R., Nishiki, M., Widrlechner, M.P. 2002. Chemical composition of essential oils from a collection of ocimum species (ncrpis, ames, usa); investigation of their antifungal activities and effects on fungal polyamines. Meeting Abstract, pp.255-257.
Technical Abstract: The North Central Regional Plant Introduction Station conserves germplasm of aromatic plants, including extensive collections of Ocimum providing valuable sources of key genes for developing new basil cultivars. We conducted chemical analyses of essential oils of 73 Ocimum accessions, comparing our results with morphological descriptions. Selected Ocimum essential oils were also tested for antifungal activity against two pathogens of Vicia faba: Uromyces viciae-fabae and Botrytis fabae. In addition, we studied these oils' effects on fungal polyamine biosynthesis, function and metabolism. Volatile-oil yields ranged from 0.3 to 4.7%. Oil of O. selloi contained methyleugenol. Ocimum gratissimum included a high-eugenol accession and several with caryophyllene as the largest component. Ocimum tenuiflorum was represented by caryophyllene, eugenol, and elemene chemotypes. We identified five distinct chemotypes of O. americanum: citral, camphor, methylcinnamate, epicamphor, and eucalyptol, and eight of O. basilicum: methylchavicol, linalol, eugenol, methyleugenol, methylchavicol/linalol, methyleugenol/linalol, citral/linalol and citral/methylchavicol. All oils and individual components displayed antifungal activity. They were effective in greenhouse experiments at concentrations of 1000 and 5000 ppm, with significant control obtained by spraying 3 hours post-, 3 days pre-, and 3 days post-inoculation. Biochemical analyses of the effects of Ocimum oils on polyamine pathways of B. fabae revealed up-regulation of the AdoMet enzyme and flux of spermine, the latter indirectly indicating an increase in spermidine synthase activity.