Study of the Essential Oil of Plectranthus Marrubioides Hochst Cultivated in Kenya

Abstract

Fran the leaves of Plectranthus marrubioides Hochst, obtained frcm a cultivation in Nairobi (at Kabete), the essential (volatile) oil was isolated. Both macroscopic and microscopic examination of the leaves was done. The study of the distilled oil was done by Thin Layer Chromatography and Gas Liquid Chromatography. Cn steam distillation the yield of the oil (calculated on moisture free basis) was 4.25% v/w. The physical properties of the oil were obtained as follows:- Specific gravity W24) : 0.9531 Refractive index (np25.4^ ; 1.4810 Optical rotation (»<D 25'4) : +4.4° The oil was found to contain at least 21 components and the major one was identified as camphor and occurred in a quantity of 74.0%. The volatile oil frcm the stems was also isolated. The yield was 0.43% v/w calculated on a moisture free basis. This oil was compared with the oil obtained from the leaves and was found to contain a slightly lower percentage of camphor (70%). Finally the volatile oil was isolated from leaves which had not been dried properly and had started rotting to see if it had undergone any changes. GLC studies showed that most of the major constituents remained unchanged.