Chemical Composition of Essential Oils of Some Medicinal Plants from Rwanda

We report the chemical compositions of the essential oils of five medicinal plants from Rwanda belonging to the Labiatae family (Lamiaceae): Leonitis nepetifolia, Leucas martinicensis, Plectranthus sylvestris, Plectranthus harbatus and Satureja pseudosimensis. Only the oil of Plectanthus harbatus had been studied previously. The main components of Leonitis nepetifolia leaf and flower oils were linalool (0.5% and 10.5%), β-caryophyllene (10.3% and 6.2%), germacrene D (41.2% and 17.0%) and δ-selinene (6.8% and 16.7%), respectively. The leaf and flower oils of Leucas martinicensis contained 1-hepten-3-ol (7.6–21.5% and 12.8–17.8%) and germacrene D (30.3–39.9% and 29.7–37.0%), respectively. The oil of Plectranthus harbatus contain α-fenchyl acetate (0.7–10%), α-copaene (3.9–7.7%), aromadendrene (8.2–23.6%), borneol (3.0–23.9%), γ-2-cadinene (1.9–4.3%), caryophyllene oxide (1.9–44.0%), T-cadinol (0.5–4.1%), calamenene hydrate and hydroxycalamenene (0.8–7.5% and 2.3–7.3%), respectively. The leaves and flowers oils of Plectranthus sylvestris were characterized by (E)-β-ocimene (6.2% and 26.0%), β-bourbonene (3.8% and 6.3%), β-caryophyllene (3.2% and 5.8%), germacrene-D (22.1% and 24.6%) and (Z,Z)-α-farnesene (22.1% and 24.6%) respectively. The oil of Satureja pseudosimensis was characterized by the presence of limonene (1.8–3.9%), menthone (1.1–18.0%), pulegone (0.2–63.4%) and piperitone oxide (0.5–71.7%).