Edible Microalgae and Their Bioactive Compounds in the Prevention and Treatment of Metabolic Alterations

Abstract

Marine and freshwater algae and their products are in growing demand worldwide because of their nutritional and functional properties. Microalgae (unicellular algae) will constitute one of the major foods of the future for nutritional and environmental reasons. They are sources of high-quality protein and bioactive molecules with potential application in the modern epidemics of obesity and diabetes. They may also contribute decisively to sustainability through carbon dioxide fixation and minimization of agricultural land use. This paper reviews current knowledge of the effects of consuming edible microalgae on the metabolic alterations known as metabolic syndrome (MS). These microalgae include Chlorella, Spirulina (Arthrospira) and Tetraselmis as well as Isochrysis and Nannochloropsis as candidates for human consumption. Chlorella biomass has shown antioxidant, antidiabetic, immunomodulatory, antihypertensive, and antihyperlipidemic effects in humans and other mammals. The components of microalgae reviewed suggest that they may be effective against MS at two levels: in the early stages, to work against the development of insulin resistance (IR), and later, when pancreatic -cell function is already compromised. The active components at both stages are antioxidant scavengers and anti-inflammatory lipid mediators such as carotenoids and -3 PUFAs (eicosapentaenoic acid/docosahexaenoic acid; EPA/DHA), prebiotic polysaccharides, phenolics, antihypertensive peptides, several pigments such as phycobilins and phycocyanin, and some vitamins, such as folate. As a source of high-quality protein, including an array of bioactive molecules with potential activity against the modern epidemics of obesity and diabetes, microalgae are proposed as excellent foods for the future. Moreover, their incorporation into the human diet would decisively contribute to a more sustainable world because of their roles in carbon dioxide fixation and reducing the use of land for agricultural purposes.

Impact of dietary Chlorella vulgaris and carbohydrate-active enzymes incorporation on plasma metabolites and liver lipid composition of broilers

“…The former authors hypothesised that the reason for the decreased plasma TAG concentration of laying hens was the inhibition of hepatic fatty acid synthesis and triacylglycerol production. Previous studies have shown that the nutritional composition of C. vulgaris may contribute to their effects on mitigating metabolic alterations through different mechanisms [ 36 , 37 ]. Several algae-derived bioactive compounds, like lipids, antioxidants, pigments, vitamins and polysaccharides are known to have beneficial effects on human and animal health [ 38 – 40 ].…”

Light and Autofluorescence, Multitasking Features in Living Organisms

“…In particular, it is to recall that Spirulina species belong to cyanobacteria and contain both chlorophyll and phycocyanins, the respective green and blue pigments involved in photosynthesis, making Spirulina species to be commonly defined as a blue-green alga. Phycocyanins exhibit special spectral properties in term of high absorbance and fluorescence yields, accounting for their photoprotection role in cyanobacteria and for more general strong antioxidant properties, which have stimulated the use of phycocyanins in nutriceutics and pharmacology, besides the use in food and pharmaceutics as a mere dye [15,50,51,[54][55][56][57][58][59]. The absorption and fluorescence properties of purified phycocyanin and allophycocyanin have been also analyzed by time-resolved techniques to investigate ultrafast kinetic components of excitation energy transfer in phycobilisome, with the aim to improve the collection of solar energy for photovoltaic applications [15].…”

“…The main fluorophores described in this section are summarized in Table 2. [10,22,23] Abiotic stress in higher plants [39] Phycocyanin Allo-phycocyanin 550-670 nm 650-700 nm Light harvesting, efficient energy conversion, photoprotection in cyanobacteria [58] Food and pharmaceutic additives [15,50,51,[54][55][56][57][58][59] Models to improve photovoltaic applications [15] * Other optical parameters besides absorption/fluorescence may have been used in some applications; excitation/emission ranges may vary depending on measurement conditions.…”

“…The pleasing effects of polyphenol derivatives on taste and color of alimentary products, along with the increasing awareness on their nutritional and healthy properties account for the gathering efforts to improve their natural content in edible vegetables or their use as additives in food and beverage. The antioxidant properties of phenolic compounds are considered the main reason for their anticancer, antidiabetic, anti-inflammatory, anti-osteoporotic and cardioprotective effects, [55,71,72,[87][88][89][90][91]. Actions on the pathways of glucose metabolism, as well as on the signaling pathways regulating cell proliferation, apoptosis, host immune response and inflammation, or on estrogenic or anti-estrogenic activity are reported in the literature to explain the manifold therapeutic effects of polyphenols, with particular attention to the cyanidin-3-O-galactoside, the colored derivative commonly present in different kinds of seeds and fruits [71,92].…”

The Nutritional Efficacy of Chlorella Supplementation Depends on the Individual Gut Environment: A Randomised Control Study

“…Chlorella contains dietary fibre such as β-glucan that is metabolised to short-chain fatty acids (SCFAs) such as propionate and butyrate, which are known to have beneficial effects on host health, by the gut microbiota (15). However, a simple comparison showed no significant difference in the faecal abundances of propionate and butyrate before and after Chlorella intake in this study (Figures 4A,C).…”