Impact of Extraction Techniques and Solvent Systems on the Antioxidant Activity and Fatty Acid Composition of Scenedesmus parvus Extracts

Abstract Scenedesmus parvus , a Malaysian freshwater microalga, has emerged as a promising source of secondary metabolites with potential applications in nutraceutical, pharmaceutical, food, and cosmetic industries. This study aimed to assess the extraction yield, total phenolic and flavonoid content, and antioxidant potential of S. parvus extracts obtained using different extraction methods, including sonication, maceration, and Soxhlet extraction methods. Additionally, the fatty acid profile and key chemical constituents of S. parvus were analyzed using gas chromatography-flame ionization detection (GC-FID). To date, this study represents one of the first comprehensive investigations into the synergistic interaction between sonication and solvent systems on the S. parvus , concurrently evaluating effects on both antioxidant activity and lipid profile. The results indicate that the sonication method with methanol as the extraction solvent yielded the highest extraction efficiency (14.65 ± 0.503%), whereas the maceration method with hexane resulted in the lowest yield (1.34 ± 0.371%). 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 with methanol as solvent demonstrated the highest antioxidant activity, as evidenced by its superior performance in both DPPH (IC50, 0.48 ± 0.035 mg mL −1 ) and ABTS⁺ (IC50, 0.13 ± 0.003 mg mL −1 ) radical scavenging assays. These findings highlight the impact of extraction methods on the yield of bioactive compounds and the antioxidant properties of S. parvus . In particular, methanol-based extraction demonstrated significant potential for obtaining high antioxidant activity and an optimal fatty acid profile, underscoring its suitability for applications in nutraceutical, pharmaceutical, food, and cosmetic formulations.