Chemical profiling and α-glucosidase inhibitory activity of essential oils extracted with two methods from some North Western Himalayan aromatic crops.

Solvent-free hydrodistillation adsorption apparatus (HDA) and normal clevenger hydrodistillation (NC) were applied to obtain Juniperus communis , Valeriana jatamansi and Hedychium spicatum essential oils (EOs). The yields, chemical compositions and α-glucosidase inhibitory activity of the EOs were investigated. Obtained EOs were analyzed using gas chromatography (GC), gas chromatography-mass spectrometry (GC-MS) and nuclear magnetic resonance (NMR) instruments. Recovery improvement was observed in HDA method (30.4%, 27.3% and 29.0% more recovery of EOs than NC method for V. jatamansi , H. spicatum and J. communis , respectively). Present results demonstrated NCV ( V. jatamansi EO (essential oil) by NC method) had highest α-glucosidase inhibitory activity with half-maximal inhibitory concentration (IC ₅₀ ) values of 8.20 μg/mL. As a result, HDA method is considered to be the promising theme for producing EOs with high production recovery. Furthermore, current findings demonstrated that the selected EOs may be a good natural antidiabetic.