In the present study, chemical constituents of the essential oil and supercritical fluid extracts of Valeriana wallichi DC obtained by hydrodistillation and supercritical fluid CO₂ extraction have been studied by GC-MS technique. Seventy six compounds were obtained from hydro distillation, representing 98.6% of the total oil. The major component of hydro distillation was isovaleric acid (37.69%), methylvaleric acid (17.24%) and seychellene (6.49%) along with many other components in minor amounts. Ninty eight and seventy six components were identified by GC-MS in the supercritical CO₂ fluid extracts extracted at 100 and 200 bar respectively, where the major components were cis-adamantane-2-carboxylic acid, 4-hydroxy (36.88%, 40.26%), isovaleric acid (5.91%, 6.75%), β-bisabolol (6.48%, 5.71%), bornyl isovalerate (5.08%, 5.54%), of the Nardostachys jatamansi extract at 200 and 100 bar respectively. Other major components present in the supercritical fluid extracts were β-methasone valerate, valeranone, benzyl isovalerate , nerolidol, methylvaleric acid and geranyl isovalerate which were usually absent or trace in the hydrodistilled essential oil. The antioxidant activity of essential oil and supercritical fluid extracts was evaluated in DPPH radical, superoxide radical, hydroxyl scavenging assays. Reducing power of those oil and extracts were also studied. Essential oil and Supercritical fluid extracts gave comparable DPPH, superoxide radical scavenging and reducing power activity and there is no much deviation among various activities was observed. However, when we consider overall antioxidant assays, 200 bar extract of valerain is the best among essential oil and extracts.

Keywords: Valeriana wallichi DC; Hydrodistillation; Supercritical Fluid CO₂ Extraction; Antioxidant Activities; GC-MS;