Anisomeles malabarica (L.) R.Br.: the essential oil chemical composition of the accession growing wild in Sri Lanka.

The genus Anisomeles R.Br. is a genus of the family Lamiaceae, including twenty-six species. Anisomeles malabarica (L.) R.Br. is a plant largely utilised in the local popular medicine as a species endemic of India and Sri Lanka. Although several researches have been carried out on its non-volatile metabolites, its essential oil results very poorly investigated. This is the first report regarding the Sri Lanka accession chemical composition of the essential oil (EO), extracted from its aerial parts. The EO (Am) was characterised by monoterpene hydrocarbons (33.77%), with α-pinene (16.42%), β-pinene (6.48%) and β-myrcene (5.68%) as the principal metabolites. Among sesquiterpene hydrocarbons (8.69%) β-caryophyllene (5.83%) was the main product. Comparing our results with the only published study on EO distilled from Indian species, notable differences emerged. It would be worth investigating whether climatic, soil, and geographic conditions cause these variations, or whether genetic differences exist between Indian and Sri Lankan plants.