Effect of individual factors on the extraction of phenolic compounds from turmeric rhizomes (Curcuma longa) and moringa leaves (Moringa oleifera

Phenolic compounds are of great interest for their high antioxidant power and their numerous health benefits. These biomolecules are present in large quantities in many food and medicinal plants, such as the rhizomes of Curcuma longa and the leaves of Moringa oleifera. However, extraction methods for these bioactive compounds underestimate the plant's potential. The aim of this study was therefore to evaluate the influence of seven factors involved in the process of extracting phenolic compounds from Curcuma longa rhizomes and Moringa oleifera leaves. The seven main factors, i.e. drying time, mesh size, ethanol concentration, solvent/sample ratio, stirring speed, temperature and extraction time, influence the extraction of total polyphenols from Curcuma longa rhizomes and Moringa oleifera leaves. However, the optimum conditions for sample drying time are 48 to 72 h for Curcuma longa rhizomes and 60 to 72 h for Moringa oleifera leaves. Those for mesh size and sample/solvent ratio are 250 to 500 µm and 1/20 to 1/10 respectively. The best solvent concentration was between 60 and 80% for Curcuma longa rhizomes and between 40 and 60% for Moringa oleifera leaves. In addition, the best stirring speed is between 200 and 300 rpm and the best extraction time between 15 and 30 min. In addition, the best extraction temperatures are between 40 and 50°C for Curcuma longa rhizomes and between 50 and 60°C for Moringa oleifera leaves. These factors should therefore be taken into account for maximum extraction of total polyphenols from Curcuma longa rhizomes and Moringa oleifera leaves.