Ultrasound-assisted exraction of phytochemicals using response surface methodology in commercial Moringa oleifera Lam leaves

Abstract

Moringa oleifera Lam is a rich source of phenolic and flavonoid compounds that act as antioxidant, antibacterial and anti-inflammatory agents. M. oleifera is one of the species belong to Moringa genus from the Moringaceae family. It also well-known as a “pokok kelor”. This research was carried out to optimize the ultrasound-assisted extraction (UAE) of the extract from commercial sample of M. oleifera leaves by using response surface methodology (RSM). Box-Behnken design (BBD) was used to design the 17 experiments using three variables which were extraction temperature (40, 50, 60°C), time (25, 30, 35 min) and methanol composition as solvent (60, 70, 80%). The effect of parameters on the responses of extraction yield, quantification of quercetin (2) and chlorogenic acid (23) as well as DPPH (2,2-diphenyl-1-picrylhydrazyl) assay for antioxidant were determined. Quantification of quercetin (2) and chlorogenic acid (23) in the extracts was done using reversed-phase high-performance liquid chromatography coupled with a diode array detector. It was discovered that both compounds were present in the optimized extracts. The highest percentage of yield (48.99%) and the concentration of chlorogenic acid (23) (31.07% w/w) were found at the extraction temperature of 50°C, time of 30 minutes and 70% of methanol. The highest antioxidant activity was also found in this condition with the IC50 value of 31.77 µg/ml. However, highest concentration of quercetin (2) (5.40% w/w) was discovered when the extraction was carried out at 50°C for 35 minutes and 80% of methanol concentration. The experimental values were closed agreed with the predicted values. The determination coefficient (R2) of extraction yield, quercetin (2), chlorogenic acids (23) and DPPH assay were 0.993, 0.9094, 0.9098 and 0.9849, respectively. The analysis of variance (ANOVA) showed a good statistical and model fitting of the quadratic model. The numerical data indicated the success of the RSM method for optimizing the parameter for extraction of phytochemicals from M. oleifera leaves. This research recommended that the ultrasound-assisted extraction method under specific parameters has favourable potential to be used in the extraction process. Therefore, this extraction process can improve the effect of efficiency on yield, quantification on phytochemicals and antioxidant activities.