Profiling of Essential Oil Constituents in Ocimum Species

Abstract

Ocimum species are herbaceous plants with great medicinal importance. Various tissues of the plants are being used in folk remedies for a variety of purposes. The pharmacologically active natural products present in essential oils in the Ocimum species belong to two major classes of natural compounds, viz. phenylpropanoids and terpenoids. In the present study, the essential oils from the inflorescence, leaf, and stem tissues of four major Ocimum species were hydro-distilled and analyzed. Gas chromatography–mass spectrometry profiling to unravel the phytomolecules and compositional quantification showed the occurrence of distinct tissue-based variability of phytomolecules. Phenylpropanoids such as eugenol and methyl chavicol were specifically found in the tissues of O. sanctum, O. gratissimum, and O. basilicum, respectively, whereas O. kilimandscharicum was distinct in possessing a terpenoid phytomolecule camphor predominantly in its tissues. The study also analyzed the uniqueness of the distribution of phytochemical constituents of essential oil in Ocimum species in tissue- and species-specific manner. Leaves were the major site of accumulation of essential oil, whereas inflorescence and stem also contained essential oil constituents albeit in low quantities.