Eighty-nine essential oil analyses carried out on Cameroonian plant material by gas chromatography are reviewed, and structures of sixty one main oil compounds are presented. Plant samples had been collected all over the rainforest area and further northwards, covering forty plant species belonging to ten families. For these plants, common names, traditional use as well as bioactivity and toxicity of their essential oils in vitro and in vivo are compiled. Data show that oils from leaves, bark, roots, fruit, rhizome or seeds display their own one to four main essential oil components. Each of them contributing more than 10% to over 90% of the oil´s volume, which sums up to species-unique essential oil fingerprints and decreasing similarity of these fingerprints with increasing phylogenetic distance between species. This review article shows that the environmental factor include, temperature, rainfall (Littoral region), humidity (Center, South, East and West regions) and solar radiation (Adamaoua, North and Far-north regions) as well as the soil nutrients influence the secondary metabolite composition of the plants. Bioassays valorized traditional use of a good number of oils, for example against the dermatophytic fungus Trichophyton rubrum being twice as effective as amphothericin B®; against the chloroquine resistant Plasmodium falciparum; against cancer cell lines; and against a variety of human pathogen bacteria, being up to ten times as effective as ciproxin®, lidaprim®, tetracycline hydrochloride® and lidaprim®. Importantly, in an experiment employing the stored product beetle Callosobruchus maculatus, the leaf oil of Lippia adoensis (Verbenaceae) indicated neurotoxicity, so that preparations should be applied with care. Follow up work may focus on bioassays with commercial pure compounds, with the goal to improve effectivity and doses calculation for traditional essential oil medicines and agricultural products. تفاصيل المقالة

Forty traditional medicinal plants from the Cameroonian rain forest belonging to twelve families are reviewed related to botanical description, taxonomy, common names, traditional use, essential oil composition as well as bioactivity and toxicity of their essential oils. A correlation is drawn between traditional use and bioactivity in vitro/in vivo, and structures of seventy-three main oil ingredients are given. Collected data indicate that plant essential oils unfold their biological activity related to functional groups of major and minor compounds, in a complex, fine-tuned interaction, modulated by environmental factors like the vegetation cycle of the plant, the altitude and the presence or absence of plant pathogen microbes, certain crop weevils as well as nematodes, varying with climatic seasons. Comparison of traditional use with laboratory results indicates effectivity of a good number of essential oils received from various plant parts, like leaves, bark, fruit, roots and rhizomes against Plasmodium falciparum, food borne microbes, dermatophytes, the malaria vector Anopheles gambiae, cancer cell lines, river blindness as well as plant pathogen weevils and fungi. However, toxicological studies are needed before any recommendation for application can be given. Importantly, leaf and fruit oil of Cupressus lusitanica (Cupressaceae) displayed strong acute toxicity in animal model, and the bark oil of Cinnamomum verum (Lauraceae) showed high toxicity in a normal cell line, so that preparations should be applied with care. Preformulation and formulation studies will be needed to develop a range of suitable dosage forms to introduce optimized pharmaceuticals (high active, low toxic) as replacement of current crude plant essential oil preparations in Cameroon and other Subsaharan countries. تفاصيل المقالة