Essential Oil Composition of Platostoma menthoides (L.) A. J. Paton whole plant

Platostoma menthoides (L.) A. J. Paton (Syn: Geniosporum prostratum (L) Benth. Geniosporum tenuiflorum) is an aromatic annual herb found in India and Sri Lanka belonging to the family Lamiaceae. Hydrodistillation of the plant collected from the North Central province in Sri Lanka, yielded 0. 5% (v/w) of a light yellow colored fragrant oil. The oil was analyzed by GC-FID and GC-MS. A total of 74 components accounting for 85.01 % of the oil were identified by comparison of their mass spectra with those in the NIST and WILEY libraries and their retention indices with published values. These compounds included sesquiterpene hydrocarbons (55.80 %), monoterpene hydrocarbons (14.77 %), oxygenated monoterpenes (8.82 %) and oxygenated sesquiterpenes (17.62 %). The main components of the oil were beta-caryophyllene (37.01 %), limonene (8.45 %), bornyl formate (5.57 %), alpha-humulene (4.70 %) and caryophyllene oxide (5.82 %). It also contained a small amount of the methoxychromene precocene 1 (0.23 %), an insect anti-juvenile hormone which has not been reported widely from the Lamiaceae or the genus Platostoma.