In Vitro Characterization of Antioxidant, Antibacterial and Antimutagenic Activities of the Green Microalga Ettlia pseudoalveolaris

Abstract

Recently, green microalgae have gained importance due to their nutritional and bioactive compounds, which makes them some of the most promising and innovative functional foods. The aim of this study was to evaluate the chemical profile and the in vitro antioxidant, antimicrobial and antimutagenic activity of an aqueous extract of the green microalga Ettlia pseudoalveolaris, obtained from the freshwater lakes of the Ecuadorian Highlands. Human microvascular endothelial cells (HMEC-1) were used to determine the ability of the microalga to reduce the endothelial damage caused by hydrogen peroxide-induced oxidative stress. Furthermore, the eukaryotic system Saccharomyces cerevisiae was used to evaluate the possible cytotoxic, mutagenic and antimutagenic effect of E. pseudoalveolaris. The extract showed a notable antioxidant capacity and a moderate antibacterial activity mostly due to the high content in polyphenolic compounds. It is likely that the antioxidant compounds present in the extract were also responsible for the observed reduction in endothelial damage of HMEC-1 cells. An antimutagenic effect through a direct antioxidant mechanism was also found. Based on the results of in vitro assays, E. pseudoalveolaris proved to be a good source of bioactive compounds and antioxidant, antibacterial and antimutagenic capacities making it a potential functional food.

Chlamydomonas agloeformis from the Ecuadorian Highlands: Nutrients and Bioactive Compounds Profiling and In Vitro Antioxidant Activity

“…The centesimal analysis showed that the microalga is rich in compounds considered of great interest for human nutrition, due to the high content in proteins, lipids, and fibers. Interestingly, the protein content was far higher than those we found in Ettlia pseudoalveolaris (13.46 ± 0.12 vs. 8.31 ± 0.12%), another species of green microalga isolated from the same sampling site of Yahuarcocha lake in the Equadorian Highland [31]. The FAs profile revealed a majority of unsaturated ones.…”

“…A previous study by Soares et al [36] aimed to characterize the FAs profile of various different species of microalgae, among which was Chlamydomonas planctogloea, of the same genus of ChA, showed much lower levels of PUFAs. Although slightly lower, we found comparable levels of ALA and LA (29.28 ± 0.12 and 14.95 ± 0.06, respectively) in the green microalga Ettlia pseudoalveolaris [31]. Nevertheless, ChA also exhibited considerable quantities of saturated fatty acids (SFAs), particularly palmitic acid (C16:0), which accounted for the majority (39.46 ± 0.25%) of the composition (Table 2).…”

“…In our previous investigation focusing on the green microalga E. pseudoalveolaris, we observed a prominent presence of verbascoside, similar to ChA, among the identified phenolic acids. Notably, the extract of this microalga exhibited a substantial antioxidant capacity and a noteworthy inhibition of growth in various Gram-positive and Gram-negative bacterial strains, which is likely attributed to the presence of this derivative of caffeic acid [31]. Further investigation would be necessary to assess whether verbascoside and the other detected phenols confer to ChA this antibacterial capacity observed for E. pseudoalveolaris.…”

“…For instance, the abundance of palmitic and stearic acids is desirable in high-quality biodiesel production, as a higher proportion of SFAs contributes to improve viscosity (flow properties) and enables the utilization of biodiesel in low-temperature environments [37]. Notably, a recent analysis of the FA profile of Chlorella vulgaris across four distinct strains and of Ettlia pseudoalveolaris highlighted palmitic acid as the predominant SFA [31,38]. Moreover, investigations on other green microalgal strains, namely T. obliquus and D. abundans, showed the prevalence of SFAs as the primary constituents in their total fatty acid methyl esters profiles, reaffirming the richness of this FA type in numerous microalgae [39].…”

Study of the Antimicrobial Potential of the Arthrospira platensis, Planktothrix agardhii, Leptolyngbya cf. ectocarpi, Roholtiella mixta nov., Tetraselmis viridis, and Nanofrustulum shiloi against Gram-Positive, Gram-Negative Bacteria, and Mycobacteria

“…NT8c, Chlorella sp. FN1, Ettlia pseudoalveolaris [ 30 , 31 ], Oscillatoriales , Nostocales [ 25 ], Amphidinium carterae [ 32 , 33 ], Chlorella vulgaris, and A. platensis [ 34 , 35 ] inhibited the growth of gram-positive and gram-negative bacteria. Linoleic, oleic, docosahexaenoic, eicosapentaenoic acids, polyphenols, amphidinolides, lipid complexes, and nanopeptides (cyclic peptides) are responsible for the antibacterial properties of extracts from cyanobacteria and microalgae.…”