Dynamics of ethyl para-methoxycinnamate in <i>Kaempferia galanga</i> L.<i> </i>with rhizome age, storage and bioefficacy of rhizome extract against mosquito larvae

Kaempferia galanga is an important medicinal plant with a major active principle, ethyl para-methoxy cinnamate (EPMC), which has diverse medicinal applications. It has a great scope for cultivation to provide raw material for EPMC extraction. The present study assessed the EPMC Content and Yield/ha in the 1st year of cultivation, the loss of EPMC in stored rhizomes, and the mosquito larvicidal effect. The plants were harvested from the 3rd-9th month of planting; morphometric observations were recorded, and EPMC content (%) was estimated by the Thin Layer Chromatography-UV-Spectrophotometer method. The assessed ranges were for EPMC content (8.077% - 18.443%) and EPMC yield/ha (4.062 kg/ha - 16.977kg/ha) on oven dry weight basis. For storage study, 2.5 yr-old harvested rhizome was cut into small sizes (10g) and stored separately under different regimes (Light, Dark), conditions (Open, Closed), and durations (0, 30, 60, and 90 days). The EPMC content was evaluated after 90 days of rhizome storage. The maximum EPMC content (2.475%) was recorded in the materials stored in open-dark conditions, a 42.638% decrease from the initial storage. The Individual effect of storage condition revealed EPMC content was higher in material stored in the dark (2.747%) than in the light (2.679%), and higher in the open condition (2.882%) than in the closed condition (2.544%). The efficacy of the ethanolic extract of K. galanga rhizome on mosquito larval mortality was studied using 7 concentrations (0, 12.5, 25, 50, 100, 150, 200 ppm) applied for 4 hours. The LC 50 value was found to be 66.433 ppm (LL: 32.234 ppm – UL:136.915 ppm) and LC 90 value found to be 201.341 ppm (LL: 97.693 ppm – UL: 414.95 ppm).