Optimization of extraction conditions for obtaining active compounds of Ulva sp.

Ulva sp., a green macroalgae known as sea lettuce, is rich in polysaccharides, proteins, minerals, and bioactive compounds with antimutagenic, anticoagulant, anticancer, anti-inflammatory, antibacterial, and nutraceutical properties. Its abundance along the Aegean Sea coast poses an environmental challenge, as it is often disposed of as waste. However, Ulva sp. holds potential for high-value products in cosmetics and dietary supplements. Optimizing the extraction of its bioactive compounds using response surface methodology involved adjusting ethanol concentration, solid/liquid ratio, and extraction time. Key responses evaluated included yield, total polysaccharides, total protein, total phenol, total antioxidant activity, alpha-glucosidase inhibitory activity, and yeast cell glucose uptake. In this study, extraction yields ranged from 0.86% to 22.47% based on variations in extraction conditions. The highest total protein content was 106.88 mg BSA/g dry extract, while the polysaccharide content was determined to be 15.42%. The highest values for total phenol content and antioxidant capacity were found to be 82.15 mg GAE/g dry extract and 63.63 mg Trolox/g dry extract, respectively. The determination of the total amounts of antioxidants and phenolic compounds in extracts may expand their potential applications. In addition, the potential application of Ulva sp extracts as inhibitors for the treatment of diabetes has been demonstrated through experiments assessing both alpha-glucosidase enzyme inhibition and glucose uptake in yeast cells. The results support an environmentally friendly approach for the utilization of Ulva sp. from waste into valuable antidiabetic products.