Exploring compositional diversity in the essential oils of 34 Ocimum taxa from Indian flora

To explore diversity in the morphological features, essential oil yield, and chemical composition of Ocimum taxa growing in foot and mid-hills of northern India; 34 populations representing five Ocimum species were collected and investigated. Essential oil yield (%v/w) was found to vary from 0.10 to 0.74% in different populations. Analyses of the essential oils by GC/FID and GC/MS and the subsequent classification by statistical analysis resulted in seven clusters with significant variations in their terpenoid compositions (cluster I: methyl chavicol/linalool; cluster II: eugenol/(Z)-β-ocimene/β-elemene/(E)-caryophyllene; cluster III: camphor/limonene; cluster IV: eugenol/(E)-caryophyllene/β-bisabolene/β-elemene/methyl chavicol/1,8-cineole; cluster V: linalool; cluster VI: methyl eugenol/(E)-caryophyllene/β-elemene; and cluster VII: citral/nerol/geraniol type). Comparison of present results with earlier reports revealed the existence of four new chemotypes in Ocimum taxa from this region.

► Diversity in the volatile oils of five Ocimum spp has been assessed.
► Thirty-four populations were collected from different locations.
► GC/MS and statistical analyses resulted in seven clusters with significant variation.
► Essential oil yield varied from 0.10% to 0.74%.
► Four new chemotypes were identified.