Determination of Antioxidant Activity from Dry Biomass of Macroalgae Cladophora Sp. Collected from Curonian Lagoon

Abstract

Introduction. One of the largest genera of green algae that can grow in both freshwater and saltwater environments is the genus Cladophora (Ulvophyceae, Chlorophyta) [1, 2]. Because of its antioxidant, anticancer, and antibacterial activities, the macroalgae Cladophora are currently being investigated as an unique and sustainable source of bioactive chemicals for both pharmaceutical and nutraceutical purposes [1]. Due to the varied nature of antioxidant activity in naturally occurring algae, it is crucial to identify its variations. The aim of this study was to determine the antioxidant activity from Cladophora sp. biomass collected in Curonian Lagoon. Materials and methods. Dry biomass of macroalgae Cladophora sp. Was received from the Nature Research Centre, Laboratory of Algology and Microbial Ecology. Different solvents, including 99.9 % and 70 % methanol and 70 % ethanol, were used for the extraction. The Soxhlet extraction, ultrasound-assisted extraction, and magnetic stirrer extraction techniques were used. 99.9 % methanol was used during a 12-hour Soxhlet extraction process. A rotary evaporator was used to evaporate the solvent at + 40 °C until the extract was dry. The dry extract was measured and produced up to a weight / volume ratio of 1:10 using distilled water. Both magnetic stirring extraction and ultrasound-assisted extraction were carried out for 2 hours at 40 °C using 70 % methanol and 70 % ethanol, respectively. The obtained extracts were used in further experiments. DPPH (2.2-diphenyl-1-picrylhydrazyl) and ABTS [2.2′-azinobis(3-ethylbenzothiazoline-6-sulpfonic acid)] methods were used to determine total antioxidant capacity, which was expressed as trolox equivalent in micromole per gram of algae dry weight (μmoL TE/g DW) [3]. Repeatability of this experiment – 3 tests. Results were statistically processed by using MS Excel software. Results and their discussion. The strongest antiradical activity in vitro was recorded for Soxhlet extraction (32.398 ± 0.115 µmoL TE/g by ABTS and 26.762 ± 2.007 µmoL TE/g by DPPH). The total antioxidant content of Cladophora sp. Extracted with 70 % ethanol using ultrasonic-assisted extraction was 10.269 ± 0.206 µmoL TE/g by ABTS and 7.329 ± 0.219 µmoL TE/g by DPPH, compared to 8.941 ± 0.087 µmoL TE/g (ABTS) and 1.198 ± 0.051 µmoL TE/g (DPPH) for the same extraction using 70 % methanol. The total antioxidant content determined by the ABTS test for magnetic stirring extraction with methanol was 9.665 ± 0.132 µmoL TE/g and 2.687 ± 0.067 µmoL TE/g by DPPH. Conclusions. The results of total antioxidant activity in the extracts of dry biomass of macroalgae Cladophora sp. show that the Soxhlet extraction with methanol had the strongest antioxidant activity in both tests followed by ultrasonic-assisted extraction using 70 % ethanol.