An extraction technique to reach the effective radical scavenging constituents from the leaves of Indonesian malva nut tree (Scaphium macropodum): A comparative study of maceration, heat-assisted, ultrasound-assisted, and microwave-assisted extraction

Abstract

Scaphium macropodum (Miq.) Beumée ex K. Heyna is an Indonesian commodity that has been widely used as an herbal medicine. This study examined the total phenolic content (TPC), flavonoid content (TFC), and antioxidant properties of Scaphium macropodum leaves. The leaves were extracted by several methods, including maceration, heat-assisted (HAE), ultrasound-assisted (UAE), and microwave-assisted extraction (MAE) using water, methanol, and ethanol solvents. The TPC value varied within the range of 14.03–97.34 mg GAE/g extract, while the TFC was not detected in water extract and ranged from 61.99 to 88.15 mg QE/g extract for alcohol solvents. The tested extracts showed great antioxidant properties by DPPH (1,1-Diphenyl-2-picrylhydrazyl) and ABTS [2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid)] radical scavenging with the inhibition percentage ranging from 3.21 to 48.62% at the concentration 25 μg/mL for DPPH and 19.48–97.44% at the concentration 20 μg/mL for ABTS assays. The statistical analysis and PCA (Principal component analysis) were conducted to obtain the proper extraction technique. The MAE method using ethanol solvent was the most suitable technique for extracting the valuable compounds of Scaphium macropodum leaves. These findings suggest the potential uses of Scaphium macropodum leaves as an alternative natural medicine with useful bioactive constituents providing good antioxidant activity.