Optimization of ultrasound assisted extraction and antioxidant activity of Phaleria Macrocarpa

Abstract

In the past decades, markets had been flooded with herbal based products including Phaleria macrocarpa (P. macrocarpa) or known as Mahkota Dewa. Previous studies reported that this plant contains high amount of active compound that are responsible for various bioactivities. However, these active compounds are sensitive towards many factors; temperature, pH, light and others in the production line. Thus, this study was conducted to optimize the extraction condition using ultrasound assisted extraction (UAE), determine the primary metabolites of the optimized extract and investigate the antioxidant activities using 2, 2-diphenyl-1-picrylhydrazine radical scavenging activity and ferric reducing antioxidant power assays. The result showed that concentration of solvent, solid to solvent ratio and sonication time affected percentage yield, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activities. The optimized parameters for the extraction are 75% methanol, 1: 31 solid to solvent ratio and 4.06 minutes of sonication time. Under these conditions, P. macrocarpa extract yielded 18.54% of crude extract, 81.59 mg GAE/g (milligram gallic acid/gram) of TPC and 28.17 mg QUE/g (milligram quercetin/gram) of TFC. Primary metabolite assays showed that P. macrocarpa optimized extract contained 40.427±1.127 mg BSA/g (milligram bovine serum albumin/gram) of protein, 23.981±0.2306 mg aescin/g of saponin and 0.853±0.0452 mg glucose/g of polysaccharides. Meanwhile, quantification of phenolic compound (gallic acid) and flavonoid compounds (quercetin, rutin and kaempferol) were done using high performance liquid chromatography and it was found that all compounds were present in the optimized extract with amount of 23.908 mg/g, 6.262 mg/g, 0.393 mg/g and 0.077 mg/g for rutin, gallic acid, kaempferol and quercetin, respectively. This extract was then tested for antioxidant activities and it exhibited potent antioxidant activities in both assays due to the relatively high TPC and TFC. This study suggested that extraction using UAE under controlled parameters contributed to the high antioxidant activities in P. macrocarpa and therefore can improve the quality of herbal products in the market.