Comparison of extraction methods of phytochemical compounds from white flower variety of Melastoma malabathricum

Phytochemical compounds from plants provide good nutrient value and give immense health benefits to human health. The selection of a suitable extraction method is vital to obtain the targeted phytochemical compounds. In this study, the phytochemical compounds in white flower variety of Melastoma malabathricum aerial parts were extracted using Conventional Soxhlet Extraction (CSE), Ultrasound-Assisted Extraction (UAE) and Modified Ultrasound-Assisted Extraction (MUAE). The extraction performance was evaluated based on phytochemical analysis including total flavonoid content (TFC), total phenolic content (TPC), total saponin, total polysaccharide and total protein contents. The antioxidant activity of M. malabathricum extract was also determined using Diphenyl-2-picrylhydrazyl (DPPH) method. The analysis results showed significant effect (p<0.05) of MUAE method on TFC, TPC, total saponin, total polysaccharide, total protein content and DPPH (64.94 mg QE/g, 538.6 mg GAE/g, 1.87 mg EE/g, 320.05 mg GE/g, 399.32 mg BSA/g and 18 µg/mL respectively). Strong correlation effects between TFC (r = 0.992) and TPC (r = 0.993) on DPPH activity were observed. More than nineteen metabolites in M. malabathricum such as flavonoids, pentacyclic triterpenes, tannins, steroid, quinic acid and triterpenoid were detected using ultra-high performance liquid chromatography coupled with orbitrap mass spectrometry, and verified based on standard mass spectra and generated theoretical fragment. These results indicate that adoption of MUAE increases the efficiency of phytochemical compounds extraction when compared to the other two extraction methods studied.