Aromatic plants of Tropical Central Africa. Part XXXII. Chemical composition and antifungal activity of thirteen essential oils from aromatic plants of Cameroon

Abstract

The essential oils of Hoslundia opposita Vahl. (leaves), Hyptis lanceolata Poit. (whole plant), Hyptis suaveolens Poit. (leaves), Ocimum basilicum L. (whole plant), Ocimum canum Sim. (whole plant), Ocimum gratissimum L. (leaves), Plectranthus glandulosus Hook (leaves), Thymus vulgaris L. (whole plant), Piper capense L. (leaves and seeds), Piper guineense Schum. et Thom. (leaves and seeds) and Bixa orellana L. (leaves) which were obtained by hydrodistillation from plants collected in different regions of Cameroon, were analysed by GC and combined GC–MS. The oils of Hoslundia opposita, Hyptis lanceolata, H. suaveolens, T. vulgaris, P. capense, P. guineense and B. orellana were found to be rich in hydrocarbons (>58%). The most abundant compounds in the oils of O. basilicum, O. canum and P. glandulosus were alcohols and oxides (>40%), while in the oil of O. gratissimum the amounts of hydrocarbons and oxygen-containing components were roughly the same. It is of interest to note the presence in O. basilicum and P. guineense (leaves) of aromatic compounds in a sizeable amount (13.5% and 25.6% respectively). The antifungal activity of these essential oils against Candida albicans, Cryptococcus neoformans, Aspergillus flavus, Aureobasidium pullulans, Microsporum gypseum, Trichophyton rubrum, and Trichoderma viride were also investigated. Two methods were used for these antifungal tests: the microatmosphere method and the standardized broth dilution micromethod. Three oils (from Ocimum gratissimum, Thymus vulgaris and Ocimum basilicum) showed strong antifungal activity. © 1998 John Wiley & Sons, Ltd.