Comparison of sequential microwave/ultrasound and microwave extraction of total phenolic compounds from Moringa oleifera L.

Abstract

Moringa oleifera is known for its high biological value and abundance of phenolic compounds. To produce extracts with a high yield of total phenolic compounds from moringa, appropriate extraction methods are required. In this study, the phenolic extraction from moringa leaves was carried out using the sequential microwave/ultrasound-assisted extraction (MUAE) method, which was compared with microwave-assisted extraction (MAE). The effects of the time and temperature during extraction process were studied on total phenolic conpounds (TPC) using Folin–Ciocalteu assay. The extracts were analyzed by fourier transform infrared spectrophotometry (FTIR). Antioxidant activity of moringa extract was tested using DPPH-scavenging activity. The results of this study show that the total phenolic compounds yield of MAE extract at 3.455 mg GAE/g and MUAE extract at 3.912 mg GAE/g. The FTIR spectrum of moringa extract showed functional groups C=O at 1652-1605 cm−1 and C-O at 1325-1113 cm−1 which indicates the presence of phenolic compounds in moringa. Antioxidant test with DPPH showed that the antioxidant activity was high in the moringa extract with an IC50 of 72.31 µg/mL for MUAE and IC50 of 80.21 µg/mL for MAE.