Investigation of Essential Oils of Plectranthus glandulosus Hook f. (Lamiaceae) from Cameroon

Abstract

The essential oil of fresh and dried leaves of Plectranthus glandulosus Hook f. [syn. Coleus laxiflorus (Benth.) Roberty] from Cameroon were analysed by GC and GC/MS. The oils were characterized by a high percentage of oxygenated monoterpenes (58.6% and 84.6% respectively) represented by cis-piperitone oxide (3.0% and 35.1%), trans-piperitone oxide (0.5% and 12.6%), fenchone (30.8% and 21.6%) and piperitenone oxide (10.9% and 6.0%). The main monoterpene hydrocarbons were terpinolene (25.2% and 7.7%), limonene (3.2% and 1.7%) and myrcene (2.2% and 1.6%). The sesquiterpene derivatives were found in a very low percentage (< 2.5%), represented mainly by germacrene D (1.4% and 1.0%).

Key Word Index:

• Plectranthus glandulosus
• Lamiaceae
• essential oil composition
• cis-piperitone oxide
• trans-piperitone oxide
• piperitenone oxide
• fenchone