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

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

A new angiotensin-converting enzyme inhibitor from Peperomia pellucida (L.) Kunth

Objective: To isolate, identify, and evaluate a new angiotensin-converting enzyme inhibitor from Peperomia pellucida (L.) Kunth herbs. Methods: A dried sample of Peperomia pellucida herb was successively macerated with n-hexane and ethyl acetate. The ethyl acetate extract solution was evaporated to obtain the crude extract. Vacuum liquid column chromatography and thin layer chromatography were performed to obtain two pure compounds. Then, both compounds were elucidated and identified using the spectroscopic method. Angiotensin-converting enzyme inhibitory activity studies of both compounds were determined using angiotensin-converting enzyme kit WST-1 with spectrophotometer microplate reader 96-well at 450 nm wavelength. Results: Two bioactive compounds were successfully isolated from Peperomia pellucida herb, including a new compound of 2,3,5-trimethoxy-9-(12,14,15-trimethoxybenzyl)-1H-indene and pellucidin A. Both compounds demonstrated angiotensin-converting enzyme inhibitory activity, with IC50 values of 72 μM (27.95 μg/mL) and 11 μM (4.4 μg/mL), respectively. Conclusions: In the present study, two active angiotensin-converting enzyme inhibitors were successfully isolated and purified from Peperomia pellucida which is used as an antihypertensive in traditional medicine, and support its use as an angiotensin-converting enzyme-inhibiting drug.