Antioxidant and Cytotoxic Effects on Tumor Cells of Exopolysaccharides from Tetraselmis suecica (Kylin) Butcher Grown Under Autotrophic and Heterotrophic Conditions

Abstract

Marine microalgae produce extracellular metabolites such as exopolysaccharides (EPS) with potentially beneficial biological applications to human health, especially antioxidant and antitumor properties, which can be increased with changes in crop trophic conditions. This study aimed to develop the autotrophic and heterotrophic culture of Tetraselmis suecica (Kylin) Butcher in order to increase EPS production and to characterize its antioxidant activity and cytotoxic effects on tumor cells. The adaptation of autotrophic to heterotrophic culture was carried out by progressively reducing the photoperiod and adding glucose. EPS extraction and purification were performed. EPS were characterized by Fourier-transform infrared spectroscopy and gas chromatography-mass spectrometry. The antioxidant capacity of EPS was analyzed by the 2,2’-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) method, and the antitumor capacity was measured by the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, showing high activity on human leukemia, breast and lung cancer cell lines. Although total EPS showed no cytotoxicity, acidic EPS showed cytotoxicity over the gingival fibroblasts cell line. Heterotrophic culture has advantages over autotrophic, such as increasing EPS yield, higher antioxidant capacity of the EPS and, to the best of our knowledge, this is the first probe that T. suecica EPS have cytotoxic effects on tumor cells; therefore, they could offer greater advantages as possible natural nutraceuticals for the pharmaceutical industry.

Preparation of Highly Substituted Sulfated Alfalfa Polysaccharides and Evaluation of Their Biological Activity

“…The study of Li [ 45 ] showed that low concentrations of polysaccharides could promote cell proliferation, and high concentrations could inhibit cell proliferation. Several studies have also shown that high concentrations of polysaccharides could inhibit the proliferation of tumor cells, and induce apoptosis [ 46 , 47 ]. They inferred that AP or SAP produce cytotoxic effects on cells with increasing concentrations, and this can lead to apoptosis.…”

Health benefits of microalgae and their microbiomes

“…Saxitoxins from T. erythraeum were also connected to mortality events in farmed pearl oysters (Negri et al ., 2004 ). Some of these cytotoxic activities may prove beneficial, for example, in the development and antitumor therapeutants; however, they will make commercial adoption of microalgae more complex (Parra‐Riofrío et al ., 2020 ).…”

Salinity-induced chemical, mechanical, and behavioral changes in marine microalgae

“…7b). A fundamental role in EPS production is played by variation in salinity, which exerts oxidative stress on cells and affects cellular ion balance (Guzman-Murillo and Ascencio 2001;Parra-Riofrío et al 2020). At lower salinity, cellular ion concentrations increased and their ion ratios were constant, whereas at salinity higher than 20, ion ratios became variable (Kirst 1990), affecting the amount of EPS production in T. suecica and its adaptation mechanisms to osmotic stress (Guzman-Murillo and Ascencio 2001).…”