Extract optimization of Ulva lactuca L. and biological activities of optimized extracts

Algae are microscopic or macroscopic organisms that can photosynthesize and are found in both freshwater and saltwater ecosystems and are considered one of the cornerstones of life. In our study, the biological activities of extracts produced under the extract conditions that provided the highest biological activity of Ulva lactuca L. were determined.

Two different methods, Response Surface Method (RSM) and Artificial Neural Network-Genetic Algorithm (ANN-GA) integration were used for optimization. In this context, the optimum extract conditions were determined as 54.940 ˚C temperature, 6.513 h, 42.109 ethanol/water ratio according to the RSM method and 56.286 ˚C temperature, 7.2793 h, 36.8625 ethanol/water ratio according to ANN-GA. The antioxidant activities of the optimized extracts were evaluated by Rel Assay kits, DPPH and FRAP methods. Anticholinesterase activities were determined by testing against acetylcholinesterase and butyrylcholinesterase enzymes. In addition, antiproliferative effects were examined in A549 lung cancer cell line and phenolic compound contents were analyzed by LC-MS/MS.

As a result of the analyzes, it was seen that the extract obtained from the conditions recommended by ANN-GA exhibited higher activities. Optimized extracts of U. lactuca were found to have potential in terms of antioxidant activities. The highest total antioxidant value was determined as 6.272 ± 0.024 mmol/L. In addition, it was determined that extracts of U. lactuca produced under optimum conditions showed strong cytotoxic effects against A549 lung cancer cell line. In addition, gallic acid, 4-hydroxybenzoic acid, caffeic acid, vanillic acid, syringic acid, quercetin and kaempferol were found in the extracts of the algae produced under optimum conditions. The highest detected compound was caffeic acid. In addition to all these properties, it was seen that U. lactuca has anticholinesterase potential in our study.

In conclusion, optimized extracts of U. lactuca attract attention with their antioxidant and cytotoxic activities as well as anticholinesterase potential and can be considered as a potential source for cancer treatment and management of neurological diseases.