Optimization of extraction method to obtain a phenolic compounds-rich extract from Moringa oleifera Lam leaves

Abstract

Moringa oleifera Lam is considered one of the most useful tree in the world because every part of the Moringa tree can be used such as nutritional supplement, for medication, and industrial purposes. Conventional solid–liquid extraction and ultrasound-assisted extraction (UAE) were performed using different solvents and mixtures of solvents with water. The total phenolic content was determined using Folin–Ciocalteu assay. UAE using ethanol:water (50:50) was the best extraction procedure, which allowed 47 ± 4 mg gallic acid equivalents (GAE)/g dry leaf to be obtained. In addition, high-performance liquid chromatography coupled to electrospray ionization quadropole-time of flight mass spectrometry (HPLC–ESI–QTOF–MS) was used to characterize the bioactive compounds in the resulting extract. Consequently, 59 compounds were tentatively characterized, phenolic acid derivatives and flavonoids being the most abundant. Furthermore, 30 of these compounds were tentatively identified for the first time in M. oleifera leaves. This study shows that leaves from M. oleifera are a good nutritional resource used as a nutritional supplement and may carry additional opportunities for food ingredient innovations, pharmaceutical and cosmetics products.