The chemical composition of essential oils obtained from the leaves of Cymbopogon giganteus Chiov. and Cymbopogon schoenanthus (L.) Spreng, two Poaceae growing wild in Benin were analyzed by GC and GC/MS. The main constituents of Cymbopogon giganteus were cis-p-mentha-1(7),8-dien-2-ol (19.4%), transp-mentha-2,8-dien-1-ol (16.4%) and limonene (13.7%). The major components identified in the oil of Cymbopogon schoenanthus were piperitone (68.4%), and δ-2-carene (11.5%). The antimicrobial activity of the essential oil of Cymbopogon giganteus was found to be moderate on Staphylococcus aureus ATCC 25923 with MIC equal to 0.32 ± 0.02 mg/mL and Escherichia coli ATCC 25922 with MIC equal to 0.64 ± 0.34 mg/mL. This same oil induced the death of 57.84% of ticks at 8µL. Therefore, essential oil of Cymbopogon schoenanthus had a low antimicrobial activity on Staphylococcus aureus ATCC 25923 with MIC equal to 2.63 ± 0.16 mg/mL and Escherichia coli ATCC 25922 with MIC equal to 2.63 ± 0.16 mg/mL.

The essential oil obtained by hydrodistillation from seeds of Syzygium aromaticum (Myrtaceae) growing in Benin was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). Twenty-one components, which represented 99.4% of the total constituents of the oil were identified. The essential oil is rich in hydrocarbons monoterpenic. The major constituents found were eugenol (60.4%), trans-β-caryophyllene (24.0%). The oil extract revealed an important antiradical activity and a high antimicrobial activity.

The chemical composition of essential oils, fatty acids and unsaponifiable of the limbs, foliars sheaths and rhizomes of Siphonochilus aethiopicus were studied by GC/MS. In petroleum ether extracts, the lipidic fractions are marked by significant rates (7.41 to 23.45 %) of fatty acids in C18. The majority of unsaponifiable compounds from the limbs, foliars sheaths and rhizomes of S. aethiopicus are essentially consist of terpenoïds accompanied by heneicosane (6.2 to 21.6 %). Otherwise, S. aethiopicus contains varied rates of catechic saponins, tanins and leucoanthocyanes in its organs.