Enantioselective GC analysis of C3-oxygenated p-menthane type Indian mentha spicata var. viridis 'Ganga' essential oil

Abstract

Essential oil of Mentha spicata L. var. viridis 'Ganga', an indigenously developed variety, was chemically profiled using various gas chromatographic techniques. Piperitenone oxide was characterized as the most exclusive constituent (69.7%) along with a new C3-oxygenated p-menthane alcohol, diosphenolene (1.6%). Enantiomeric discrimination revealed (4S)-(-)-limonene, (R)-(-)-linalool and (1S,2S)-(+)-piperitenone oxide as predominant enantiomers. The oil contained mainly C3-oxygenated p-menthane monoterpenoids, which are distinctive of peppermint, instead of the characteristic C6-oxygenated class of spearmint. The present findings will aid in understanding the pathway and cause of C3-oxygenation in a spearmint taxon. The essential oil and pure piperitenone oxide showed growth inhibiting properties and thus, may be utilized in antifungal preparations for disease management of medicinal and aromatic plants.