Reconfiguring extraction of phenolics & flavonoids through a solvent-free gravity assisted model for the complete recovery of target analytes from moringa leaves: A complete overhauling attempt in the field of botanical extraction

Abstract

In this study solvent-free microwave extraction has been emphasized as a green tool kit for complete recovery of phenolic and flavonoid principles from fresh moringa leaves (80% w/w moisture content). Extraction comprised of exposure of fresh moringa leaves to different microwave power levels (170 W, 255 W, 340 W, 425 W, 510 W, and 595 W) in short cycles of 5 min each till the last drop of the extract was obtained. A three-stage performance evaluation policy (total phenolics/flavonoid content, HPTLC profiling, and antioxidant activity) was adopted for performance evaluation. The highest TPC (67.3 mg GAE/gm of dried extract) and TFC (117.78 mg QE/gm of dried extract) value was obtained when operated at 510 W microwave power level which lasted for 5 cycles of 5 min each. The maximum content of chlorogenic acid (776.35 μg/gm of dried extract), gallic acid (56.23 μg/gm of dried extract), quercetin (17.02 μg/gm of dried extract) and p-coumaric acid (60.33 μg/gm of dried extract) was found from the same operating condition as well. The highest % scavenging activity of 69.5% was also reported for the extract obtained at 510 W power level. Extraction was found to obtain its peak at the 3rd cycle of 510 W power level. Results were in sync with SEM and chemomicroscopic studies. Such technology not only provides automation but also gives us the comfort of “push a button and walk away”, the need of the hour.