Optimizing Extraction of total phenolic Compounds in Sargassum sp. and sea lettuce (Ulva sp.) in Chabahar coastal waters using ultrasonic method

The phenolic compounds contain antioxidant properties that can be effective in the treatment of some chronic and malignant diseases. The aim of this study was to determine optimal conditions for extraction of total phenolic compounds from Sargassum sp. and Sea lettuce (Ulva sp.) in Chabahar coastal waters. The extracts of these two algae were extracted by ultrasonic method and then the different parameters consisting of solvent type (water, methanol, ethanol, or acetone), sample size (63, 125, 250, or 500 micron) and dry sample (0.1, 0.2, 0.3, 0.4, or 0.5 g) in 10 ml solvent and ultrasonic time (10, 20, or 30 mins) and temperatures (20, 40, 50, or 60°C) were optimized. The determination of total phenolic compounds were done by spectrophotometric method using Folin ciocalteu reagent and standard curve gallic acid. Maximum total phenol content was obtained by water as a solvent, particle size of 125 microns for Sargassum sp. and 250 microns for Ulva sp., dry extract of 0.1 g per 10 ml solvent for Sargassum sp. and dry extract of 0.2 g per 10 ml solvent for Ulva sp. and ultrasonic time of 10 minutes at 40 ° C for both algae. Under the optimized conditions, the highest total phenolic compounds were obtained for Sargassum algae (i.e.5.58 ± 0.271 mg gallic acid per gram of dry sample) and for Sea lettuce (i.e.2.047 ± 0.258 mg gallic acid per gram of dry sample). The results of the study showed that Sargasum algae can be used as a appropriate natural marine antioxidant source in the food and pharmaceutical industries as well.