Evaluation of yield, quality and antioxidant activity of essential oil of in vitro propagated Kaempferia galanga Linn

Objective: To determine chemical constituents and antioxidant properties of essential oil from rhizome of the medicinal plant, Kaempferia galanga (K. galanga) Linn. (Zingiberaceae) in conventionally propagated (CP) and in vitro propagated (IVP) plants. Methods: In vitro (micro) propagation of K. galanga was done by inoculating explants on to Murashige and Skoog agar medium, supplemented with suitable combinations of phytohormones; the regenerants were transferred to soil for further growth. Essential oil preparations of both CP and IVP rhizomes grown in soil, obtained by the hydro-distillation method were analyzed by gas chromatography-mass spectrometry. Antioxidant activities of essential oil samples were monitored. Results: Maximum numbers of regenerated shoots were found in the medium supplemented with 1 mg/L benzyl adenine and 0.5 mg/L indole-3-acetic acid. A total of 6 compounds were identified from rhizomes from CP and IVP plants that yielded 96.9% and 97.81% of the total oil contents, respectively. The major compound of rhizome oil identified from CP and IVP rhizomes was ethyl p-methoxy cinnamate in quantities, 82.01% and 71.77%, respectively, without any compositional variation. Antioxidant properties of essential oil preparations were assessed by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide radical scavenging assays. Moreover, antioxidant activities of rhizome-oil from IVP plants were better than that of CP oil samples. Conclusions: As IVP rhizomes had better oil yield, those could be used for a large scale commercial propagation for sustainable use of essential oil. The principal chemical in the essential oil, ethyl p-methoxy cinnamate could help apothecary, for several ailments.