Design of ionic liquid-based microwave-assisted extraction of flavonoids from Cyclea barbata Miers. and its lipoxygenase inhibitory activity

ABSTRACT

Green grass jelly (Cyclea barbata Miers.) is a plant from Indonesia that is believed to have anti-inflammatory activity.This study aims to find the optimum condition in grass jelly extraction using the ionic liquid-microwave assistedextraction toward total flavonoid content (TFC) and lipoxygenase activity (LIA). The experimental design wasperformed using the parameters variable including extraction time, liquid–solid ratio, and ionic liquids concentrationto obtain the optimum condition. The optimization analysis used response surface methodology (RSM) with Box–Behnken design (17 trials) to obtain a predictive model with TFC and LIA as a response surface value. In the presentstudy, the optimum condition was suggested by RSM analysis with parameter variables, including extraction time of17 minutes, 1-butyl-3-methylimidazolium bromide ([BMIM]Br) concentration of 1.76 mol/l, and the liquid–solid ratioof 38.21 ml/g. The equation of regression quadratic model was obtained to predict TFC and LIA as follows TFC =2.43A + 2.43B + 1.42C + 0.33AB − 3.20AC − 0.46BC − 4.90A2 − 3.10B2 − 3.10C2 + 28.32 with R2 = 0.8336 and LIA= 0.066A + 8.22B + 0.97C + 2.47AB − 5.86AC + 1.96BC − 9.99A2 − 13.75B2 − 13.11C2 + 63.53 with R2 = 0.9207,respectively