Essential oil composition, phenolics and antioxidant activities of Valeriana jatamansi at different phenological stages

Abstract

Valeriana jatamansi Jones is an important herbaceous plant of the Caprifoliaceae family used for the treatment of insomnia and stress-related disorders, due to its sedative and anxiolytic properties. In the present study, aerial parts and roots of the species collected in three phenological stages (pre-flowering, flowering and post-flowering) from three natural populations located at an altitudinal gradient were analysed for essential oil composition, phenolics, and antioxidant activity. Essential oil obtained from rhizomes exhibited qualitative and qualitative variations in growth phenophases along the altitudes. Methanolic extracts of aerial parts and roots revealed that the majority of phenolic compounds such as, gallic acid, catechin, chlorogenic acid, hydroxybenzoic acid, caffeic acid and p-coumaric acid, varied largely among different phenological stages along the altitudes. Pre-flowering stage was found to possess maximum concentration of phenolics, flavonoids and higher antioxidant activity in the aerial parts and roots. Findings from this study highlighted that the pre-flowering stage is the most suitable time for harvesting to obtain maximum phytochemicals and antioxidant activity. Further, high level of few phenolics in per-flowering stage at high altitude, suggested the requirement of compound-specific agro-climatic techniques to obtain commercial benefits from the cultivation of V. jatamansi.