Influence of extraction method and solvent system on the antioxidant activity of Scenedesmus parvus extract

Scenedesmus parvus , a Malaysian freshwater microalga, has garnered attention as a promising source of secondary metabolites with applications in various industries, including nutraceuticals, pharmaceuticals, food, and cosmetics. This study aimed to evaluate the extraction yield, total phenolic and flavonoid content, and antioxidant potential of S. parvus extracts obtained through different extraction methods (sonication, non-sonication, and soxhlet). Additionally, the fatty acid profile and key chemical constituents of S. parvus were analysed using GC-FID. Results revealed that the sonication method utilizing methanol as the extraction solvent yielded the highest extraction yield (14.5 ± 1.5%), whereas the non-sonication method employing hexane yielded the lowest (1.34 ± 0.2%). Furthermore, the sonicated ethanol extract exhibited the highest total phenolic content (66.32 ± 0.818 mg GAE g ^− 1 DW) and total flavonoid content (684.45 ± 28.928 mg QE g ^− 1 DW). Soxhlet extraction demonstrated superior antioxidant activity in both DPPH (IC50: 0.48 ± 0.035 mg mL ^− 1 ) and ABTS+ (IC50: 0.13 ± 0.003 mg mL ^− 1 ) scavenging assays compared to the others. These findings highlight the potential of different extraction methods from S. parvus , particularly those obtained with methanol as the extraction solvent, as valuable sources of natural antioxidants for application in nutraceuticals, pharmaceuticals, food, and cosmetics.