Antioxidant and anti-diabetic properties of Spirulina platensis produced in Turkey

Submerged and Solid-State Fermentation of Spirulina with Lactic Acid Bacteria Strains: Antimicrobial Properties and the Formation of Bioactive Compounds of Protein Origin

The aim of this study was to investigate the changes in bioactive compounds (L-glutamic acid (L-Glu), gamma-aminobutyric acid (GABA) and biogenic amines (BAs)) during the submerged (SMF) and solid-state (SSF) fermentation of Spirulina with lactobacilli strains (Lacticaseibacillus paracasei No. 244; Levilactobacillus brevis No. 173; Leuconostoc mesenteroides No. 225; Liquorilactobacillus uvarum No. 245). The antimicrobial properties of the untreated and fermented Spirulina against a variety of pathogenic and opportunistic strains were tested. The highest concentrations of L-Glu (3841 mg/kg) and GABA (2396 mg/kg) were found after 48 h of SSF with No. 173 and No. 244 strains, respectively. The LAB strain used for biotreatment and the process conditions, as well as the interaction of these factors, had statistically significant effects on the GABA concentration in Spirulina (p ≤ 0.001, p = 0.019 and p = 0.011, respectively). In all cases, the SSF of Spirulina had a higher total BA content than SMF. Most of the fermented Spirulina showed exceptional antimicrobial activity against Staphylococcus aureus but not against the other pathogenic bacteria. The ratios of BA/GABA and BA/L-Glu ranged from 0.5 to 62 and from 0.31 to 10.7, respectively. The GABA content was correlated with putrescine, cadaverine, histamine, tyramine, spermidine and spermine contents. The L-glutamic acid concentration showed positive moderate correlations with tryptamine, putrescine, spermidine and spermine. To summarize, while high concentrations of desirable compounds are formed during fermentation, the formation of non-desirable compounds (BAs) must also be considered due to the similar mechanism of their synthesis as well as the possibility of obtaining high concentrations in the end products.

Microalgal bioactive metabolites as promising implements in nutraceuticals and pharmaceuticals: inspiring therapy for health benefits

The rapid increase in global population and shrinkage of agricultural land necessitates the use of cost-effective renewable sources as alternative to excessive resource-demanding agricultural crops. Microalgae seem to be a potential substitute as it rapidly produces large biomass that can serve as a good source of various functional ingredients that are not produced/synthesized inside the human body and high-value nonessential bioactive compounds. Microalgae-derived bioactive metabolites possess various bioactivities including antioxidant, anti-inflammatory, antimicrobial, anti-carcinogenic, anti-hypertensive, anti-lipidemic, and anti-diabetic activities, thereof rapidly elevating their demand as interesting option in pharmaceuticals, nutraceuticals and functional foods industries for developing new products. However, their utilization in these sectors has been limited. This demands more research to explore the functionality of microalgae derived functional ingredients. Therefore, in this review, we intended to furnish up-to-date knowledge on prospects of bioactive metabolites from microalgae, their bioactivities related to health, the process of microalgae cultivation and harvesting, extraction and purification of bioactive metabolites, role as dietary supplements or functional food, their commercial applications in nutritional and pharmaceutical industries and the challenges in this area of research.

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Naturally Occurring Functional Ingredient from Filamentous Thermophilic Cyanobacterium Leptolyngbya sp. KC45: Phytochemical Characterizations and Their Multiple Bioactivities

Cyanobacteria are rich in phytochemicals, which have beneficial impacts on the prevention of many diseases. This study aimed to comprehensively characterize phytochemicals and evaluate multifunctional bioactivities in the ethanolic extract of the cyanobacterium Leptolyngbya sp. KC45. Results found that the extract mainly contained chlorophylls, carotenoids, phenolics, and flavonoids. Through LC-ESI-QTOF-MS/MS analysis, 38 phenolic compounds with promising bioactivities were discovered, and a higher diversity of flavonoids was found among the phenolic compounds identified. The extract effectively absorbed the harmful UV rays and showed high antioxidant activity on DPPH, ABTS, and PFRAP. The extract yielded high-efficiency inhibitory effects on enzymes (tyrosinase, collagenase, ACE, and α-glucosidase) related to diseases. Interestingly, the extract showed a strong cytotoxic effect on cancer cells (skin A375, lung A549, and colon Caco-2), but had a much smaller effect on normal cells, indicating a satisfactory level of safety for the extract. More importantly, the combination of the DNA ladder assay and the TUNEL assay proved the appearance of DNA fragmentation in cancer cells after a 48 h treatment with the extract, confirming the apoptosis mechanisms. Our findings suggest that cyanobacterium extract could be potentially used as a functional ingredient for various industrial applications in foods, cosmetics, pharmaceuticals, and nutraceuticals.