Assessment of the Essential Oil Composition in Ocimum species of Uttarakhand

The constituents of essential oils isolated by hydro-distillation of the aerial parts of six Ocimum species were examined by Gas Chromatography-Mass Spectrometry (GC-MS). Highest percentage of essential oils (dry weight basis) was found in O. kilimandscharium (2.47 %) and lowest in O. tenuiflorum green type (0.65 %). On fresh weight basis, the percentage of essential oils was highest in O. b. var. glabratum (0.76 %) and lowest in O. viride (0.001 %). A total of eight major components were identified. The oil of O. b. var. basilicum contained, as main components, methyl chavicol and linalool. Major compound in O. b. var. pilosum was methyl chavicol; in O.b. var. glabratum, O. b. var. thyrsiflora and O. b. var. difforme was linalool; beta cedrcne and linalool in O. b. var. purpurascens: methyl chavicol in O. citriodorum; camphor and 1,8-cineole in O. kilimandascharium; beta bisabolene and 1,8-cineole in O. viride; eugenol in O. tenuiflorum, and eugenol and methyl eugenol in O. gratissimum.