Optimization of Microwave-Assisted Extraction of AntioxidantCompounds from Vitex negundo Leaves using Response SurfaceMethodology

Abstract

IntroductionPolyphenolic substances are obtained from the leaves of Vitex negundo has gained attention for its therapeutic benefits. ObjectivesTo obtain the maximized antioxidant-rich polyphenolic substances from the Vitex negundo leaves via microwave-assisted extraction (MAE). Material and MethodsBox-Behnken design (BBD) was employed to evaluate the influence of several variables of MAE on the total phenolic content (TPC) and total flavonoid content (TFC) as determined by Folin-Ciocalteu assay method and Aluminum Chloride assay method, and the antioxidant capacity as measured by DPPH and ABTS assay methods, respectively. Response surface methodology (RSM) was used for finding optimal extraction conditions. GC-MS analysis was conducted on the extract. The tocopherol content and anticancer potential were also estimated using HPLC and MTT assay respectively. ResultsThe ideal extraction parameters were found to be 14 minutes, 48 {degrees}C, 65 % (v/v) methanol concentration, and 14 mL of extraction solvent. The optimum experiment conditions produced the TPC and TFC values of 1.46 mg GAE/g extract and 1.06 mg QE/g extract respectively. Furthermore, the DPPH and ABTS assays results showed the optimum values of 53 % and 77 % respectively. 12 bioactive compounds were identified using GC-MS. The amount of tocopherol was found to be 414.87 {micro}g/g. Lastly, the obtained leaf extract was demonstrated its anticancer potential on PC3 cell lines. ConclusionThe findings demonstrated leaf extracts potential as a useful source of polyphenols with strong antioxidant qualities that can be used in a variety of pharmaceutical applications.