Chemistry and characterization of high value acyclic alcohols in Ocimum africanum Lour. hybrids and their biological potential

Ocimum africanum Lour., a lemon-scented, short-lived annual basil is well known for its high citral content and essential oil yield. Besides its usages as food flavouring agent, fragrance intermediates are the other noteworthy applications. In the present study, we report herein a new chemical composition including biological activities in essential oils obtained from aerial parts of three selected hybrids of O. africanum L. The essential volatile fractions were analysed using gas chromatography coupled with either flame-ionization detector (FID) or mass spectrometer, enantio GC-FID, NMR and Simultaneous Thermogravimetric Analyser (STA) techniques. The oil compositions comprising different plant parts (aerial parts, leaves, and inflorescence) accounted for 92.0–97.0 % of the total composition. The aerial parts, leaves, and inflorescence marked the presence of camphor (8.0–13.6 %), nerol (17.1–24.7 %), neral (14.9–18.1 %), geraniol (5.2–13.5 %), geranial (19.5–23.1 %), β-caryophyllene (1.5–2.3 %), germacrene D (1.6–3.0 %), and trans -α-bisabolene (1.3–2.3 %). In the contrary, the oil extracted from inflorescence of hybrids contained higher nerol (24.7 %) and geraniol (13.5 %) proportions. The single enantiomers of (+)-camphor and (−)-germacrene D were observed and separated using a substituted β-cyclodextrin phase chiral column. The essential oils found effective in terms of their acetylcholinesterase and neuroinflammatory inhibitory potential against BV2 cells in Swiss albino mice. The fingerprints of studied hybrids contained a distinct oil profile vis-a-vis aldehydes, previously reported in O. africanum L. • Developed some unique inter-specific hybrids of Ocimum africanum L. • Acyclic monoterpene classes such alcohol, ketone, aldehyde and esters identified. • Nerol was identified in high proportions in inflorescence oil first time. • Single enantiomers of (+)-camphor and (−)-germacrene D were recorded. • Oils possess acetylcholinesterase and neuro-inflammatory inhibitory activities.