Sulfated polysaccharides from Phaeodactylum tricornutum: isolation, structural characteristics, and inhibiting HepG2 growth activity in vitro

Extraction of polysaccharides from Maca enhances the treatment effect of 5-FU by regulating CD4+T cells

In our previous studies, we used a graded alcohol precipitation method to extract four maca polysaccharide components (MCP1, MCP2, MCP3, and MCP4) from maca with various molecular weights. Compared to other three components, MCP2 had stronger immunoregulatory abilities on CD4⁺T cells. To avoid the immunosuppressive effect of 5-fluorouracil (5-FU), maca polysaccharides in combination with 5-FU treatment were investigated in this study. The results show that 500 mg/kg and 1000 mg/kg MCP2 could significantly delay the growth of tumor and enhance the anti-tumor effect of 5-FU in vivo. Furthermore, MCP2 can partly recover the proliferation of CD4⁺T cells after being suppressed by 5-FU in vitro. Additionally, in order to explore the mechanism in which MCP2 acts on CD4⁺T cells, the MCP2 is marked with FITC fluorescence and synthesis MCP2-Tyr-FITC for the first time. Confocal microscope results show that MCP2-Tyr-FITC can directly bind to the surface of CD4⁺T cells. Together, our work demonstrates that maca polysaccharides could enhance the anti-tumor effect when combined with 5-FU by regulating CD4⁺T cells, suggesting a novel potential immunomodulator in tumor therapy.

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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Reconciling the Gap between Medications and their Potential Leads: The Role of Marine Metabolites in the Discovery of New Anticancer Drugs: A Comprehensive Review

One-third of people will be diagnosed with cancer at some point in their lives, making it the second leading cause of death globally each year after cardiovascular disease. The complex anticancer molecular mechanisms have been understood clearly with the advent of improved genomic, proteomic, and bioinformatics. Our understanding of the complex interplay between numerous genes and regulatory genetic components within cells explaining how this might lead to malignant phenotypes has greatly expanded. It was discovered that epigenetic resistance and a lack of multitargeting drugs were highlighted as major barriers to cancer treatment, spurring the search for innovative anticancer treatments. It was discovered that epigenetic resistance and a lack of multitargeting drugs were highlighted as major barriers to cancer treatment, spurring the search for innovative anticancer treatments. Many popular anticancer drugs, including irinotecan, vincristine, etoposide, and paclitaxel, have botanical origins. Actinomycin D and mitomycin C come from bacteria, while bleomycin and curacin come from marine creatures. However, there is a lack of research evaluating the potential of algae-based anticancer treatments, especially in terms of their molecular mechanisms. Despite increasing interest in the former, and the promise of the compounds to treat tumours that have been resistant to existing treatment, pharmaceutical development of these compounds has lagged. Thus, the current review focuses on the key algal sources that have been exploited as anticancer therapeutic leads, including their biological origins, phytochemistry, and the challenges involved in converting such leads into effective anticancer drugs.

An Overview of Antitumour Activity of Polysaccharides

Cancer incidence and mortality are rapidly increasing worldwide; therefore, effective therapies are required in the current scenario of increasing cancer cases. Polysaccharides are a family of natural polymers that hold unique physicochemical and biological properties, and they have become the focus of current antitumour drug research owing to their significant antitumour effects. In addition to the direct antitumour activity of some natural polysaccharides, their structures offer versatility in synthesizing multifunctional nanocomposites, which could be chemically modified to achieve high stability and bioavailability for delivering therapeutics into tumor tissues. This review aims to highlight recent advances in natural polysaccharides and polysaccharide-based nanomedicines for cancer therapy.

Antioxidant, Immunomodulatory and Potential Anticancer Capacity of Polysaccharides (Glucans) from Euglena gracilis G.A. Klebs

The present study was carried out to determine the bioactivity of polysaccharides extracted from Euglena gracilis (EgPs). These were characterized by FT-IR and GC-MS. Cytotoxicity analyses (MTT) were performed on healthy human gingival fibroblast cell lines (HGF-1), obtaining an IC₅₀ of 228.66 µg mL^-1, and cell lines with anticancer activity for colon cancer (HCT-116), breast cancer (MCF-7), human leukemia (U-937, HL-60) and lung cancer (NCl-H460), showing that EgPs have anticancer activity, mainly in HTC-116 cells (IC₅₀ = 26.1 µg mL^-1). The immunological assay determined the immunomodulatory capacity of polysaccharides for the production of proinflammatory cytokines IL-6 and TNF-α in murine macrophages (RAW 264.7) and TNF-α in human monocytes (THP-1). It was observed that the EgPs had a stimulating capacity in the synthesis of these interleukins. The antioxidant capacity of polysaccharides and their biomass were analyzed using the ABTS method (18.30 ± 0.14% and (5.40 ± 0.56%, respectively, and the DPPH method for biomass (17.79 ± 0.57%). We quantitatively profiled HGF-1 proteins by liquid chromatography-tandem mass spectrometry analysis, coupled with 2-plex tandem mass tag labelling, in normal cells. In total, 1346 proteins were identified and quantified with high confidence, of which five were considered to be overexpressed. The data is available through ProteomeXchange, under identifier PXD029076.

Microalgae-derived polysaccharides: Potential building blocks for biomedical applications

In recent years, the increasing concern about human health well-being has strongly boosted the search for natural alternatives that can be used in different fields, especially in biomedicine. This has put microalgae-based products in evidence since they contain many bioactive compounds, of which polysaccharides are attractive due to the diverse physicochemical properties and new or improved biological roles they play. Polysaccharides from microalgae, specially exopolysaccharides, are critically important for market purposes because they can be used as anti-inflammatory, immunomodulatory, anti-glycemic, antitumor, antioxidant, anticoagulant, antilipidemic, antiviral, antibacterial, and antifungal agents. Therefore, to obtain higher productivity and competitiveness of these naturally available compounds, the cultivation parameters and the extraction/purification processes must be better optimized in order to bring perspectives for the exploitation of products in commercial and clinical practice. In this sense, the objective of the present review is to elucidate the potential biomedical applications of microalgae-derived polysaccharides. A closer look is taken at the main polysaccharides produced by microalgae, methods of extraction, purification and structural determination, biological activities and their applications, and current status.

Media engineering in marine diatom Phaeodactylum tricornutum employing cost-effective substrates for sustainable production of high-value renewables

Phaeodactylum tricornutum is a marine diatom, rich in omega-3 polyunsaturated fatty acids especially eicosapentaenoic acid (EPA) and brown pigment, that is, fucoxanthin. These high-value renewables (HVRs) have a high commercial and nutritional relevance. In this study, our focus was to enhance the productivities of such renewables by employing media engineering strategy via., photoautotrophic (P1, P2, P3) and mixotrophic (M1, M2, M3, M4) modes of cultivation with varying substrate combinations of carbon (glycerol: 0.1 m) and nitrogen (urea: 441 mm and/or sodium nitrate: 882 mm). Our results demonstrate that mixotrophic [M4] condition supplemented with glycerol (0.1 m) and urea (441 mm) feed enhanced productivities (mg L^-1  day^-1 ) as follows: biomass (770.0), total proteins (36.0), total lipids (22.0), total carbohydrates (23.0) with fatty acid methyl esters (9.6), EPA (2.7), and fucoxanthin (1.1), respectively. The overall yield of EPA represents 28% of total fatty acids in the mixotrophic [M4] condition. In conclusion, our improved strategy of feeding urea to a glycerol-supplemented medium defines a new efficient biomass valorization paradigm with cost-effective substrates for the production of HVRs in oleaginous diatoms P. tricornutum.

Recent Advancements and Future Perspectives of Microalgae-Derived Pharmaceuticals

Microalgal cells serve as solar-powered factories that produce pharmaceuticals, recombinant proteins (vaccines and drugs), and valuable natural byproducts that possess medicinal properties. The main advantages of microalgae as cell factories can be summarized as follows: they are fueled by photosynthesis, are carbon dioxide-neutral, have rapid growth rates, are robust, have low-cost cultivation, are easily scalable, pose no risk of human pathogenic contamination, and their valuable natural byproducts can be further processed. Despite their potential, there are many technical hurdles that need to be overcome before the commercial production of microalgal pharmaceuticals, and extensive studies regarding their impact on human health must still be conducted and the results evaluated. Clearly, much work remains to be done before microalgae can be used in the large-scale commercial production of pharmaceuticals. This review focuses on recent advancements in microalgal biotechnology and its future perspectives.

Microalgae Polysaccharides: An Overview of Production, Characterization, and Potential Applications

Microalgae and cyanobacteria are photosynthetic microorganisms capable of synthesizing several biocompounds, including polysaccharides with antioxidant, antibacterial, and antiviral properties. At the same time that the accumulation of biomolecules occurs, microalgae can use wastewater and gaseous effluents for their growth, mitigating these pollutants. The increase in the production of polysaccharides by microalgae can be achieved mainly through nutritional limitations, stressful conditions, and/or adverse conditions. These compounds are of commercial interest due to their biological and rheological properties, which allow their application in various sectors, such as pharmaceuticals and foods. Thus, to increase the productivity and competitiveness of microalgal polysaccharides with commercial hydrocolloids, the cultivation parameters and extraction/purification processes have been optimized. In this context, this review addresses an overview of the production, characterization, and potential applications of polysaccharides obtained by microalgae and cyanobacteria. Moreover, the main opportunities and challenges in relation to obtaining these compounds are highlighted.

Production of Algal Biomass and High-Value Compounds Mediated by Interaction of Microalgal Oocystis sp. KNUA044 and Bacterium Sphingomonas KNU100

There is growing interest in the production of microalgae-based, high-value by-products as an emerging green biotechnology. However, a cultivation platform for Oocystis sp. has yet to be established. We therefore examined the effects of bacterial culture additions on the growth and production of valuable compounds of the microalgal strain Oocystis sp. KNUA044, isolated from a locally adapted region in Korea. The strain grew only in the presence of a clear supernatant of Sphingomonas sp. KNU100 culture solution and generated 28.57 mg/l/d of biomass productivity. Protein content (43.9 wt%) was approximately two-fold higher than carbohydrate content (29.4 wt%) and lipid content (13.9 wt%). Oocystis sp. KNUA044 produced the monosaccharide fucose (33 μg/mg and 0.94 mg/l/d), reported here for the first time. Fatty acid profiling showed high accumulation (over 60%) of polyunsaturated fatty acids (PUFAs) compared to saturated (29.4%) and monounsaturated fatty acids (9.9%) under the same culture conditions. Of these PUFAs, the algal strain produced the highest concentration of linolenic acid (C18:3 ω3; 40.2%) in the omega-3 family and generated eicosapentaenoic acid (C20:5 ω3; 6.0%), also known as EPA. Based on these results, we suggest that the application of Sphingomonas sp. KNU100 for strain-dependent cultivation of Oocystis sp. KNUA044 holds future promise as a bioprocess capable of increasing algal biomass and high-value bioactive by-products, including fucose and PUFAs such as linolenic acid and EPA.

Medicinal Prospects of Antioxidants From Algal Sources in Cancer Therapy

Though cancer therapeutics can successfully eradicate cancerous cells, the effectiveness of these medications is mostly restricted to several deleterious side effects. Therefore, to alleviate these side effects, antioxidant supplementation is often warranted, reducing reactive species levels and mitigating persistent oxidative damage. Thus, it can impede the growth of cancer cells while protecting the normal cells simultaneously. Moreover, antioxidant supplementation alone or in combination with chemotherapeutics hinders further tumor development, prevents chemoresistance by improving the response to chemotherapy drugs, and enhances cancer patients' quality of life by alleviating side effects. Preclinical and clinical studies have been revealed the efficacy of using phytochemical and dietary antioxidants from different sources in treating chemo and radiation therapy-induced toxicities and enhancing treatment effectiveness. In this context, algae, both micro and macro, can be considered as alternative natural sources of antioxidants. Algae possess antioxidants from diverse groups, which can be exploited in the pharmaceutical industry. Despite having nutritional benefits, investigation and utilization of algal antioxidants are still in their infancy. This review article summarizes the prospective anticancer effect of twenty-three antioxidants from microalgae and their potential mechanism of action in cancer cells, as well as usage in cancer therapy. In addition, antioxidants from seaweeds, especially from edible species, are outlined, as well.

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

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.

Anti-bacterial, anti-scavenging and cytotoxic activity of garden cress polysaccharides

Plants polysaccharides are an infinite stock of drug composites with varying pharmacological and biological activities. The present investigation aimed to examine the antibacterial, anti-scavenging and cytotoxic potential of garden cress (GC) polysaccharides. The antibacterial effects vs Escherichia coli and as well as Staphylococcus aureus of GC polysaccharides were examined by means of agar diffusion assay, minimum inhibitory concentration (MIC), outer and inner cell membrane permeability. Antioxidant potential of the GC polysaccharides were performed by free radical DPPH scavenging, superoxide anion scavenging, hydroxyl radical scavenging, reducing power potential assay, and hydrogen peroxide method. Cytotoxicity potential of GC polysaccharides were evaluated by MTT assay in human cervical (HeLa) and liver carcinoma (HepG2) cell lines. The findings showed that GC polysaccharides MIC were 1.06 and 0.56 mg mL^-1 against E. coli and S. aureus, respectively. Compared to the standard inhibitor, the GC polysaccharides showed essential inhibitor assays in a very dose dependent approach, and notable actions to scavenge reactive oxygen species (ROS) are also due to the large quantities of hydrophilic polyphenols. The IC₅₀ values of all tested parameters were measured against standard ascorbic acid antioxidant agent. The GC polysaccharides diminish the cell viability percentage of HeLa and HepG2 in a concentration dependent manner. GC polysaccharides at a dose of 500 µg ml^-1 exhibited higher anti-tumor activity in both HeLa (65.33 ± 3.75%) and HepG2 (60.33 ± 3.48%). The findings obtained in this study indicate that GC polysaccharides has antibacterial and has a possible source of natural antioxidant and also has cytotoxic effect on different carcinoma cell lines.

PRP1, a heteropolysaccharide from Platycodonis Radix, induced apoptosis of HepG2 cells via regulating miR-21-mediated PI3K/AKT pathway

Two polysaccharides (PRP1 and PRP2) were isolated from Platycodonis Radix. Preliminary structural analysis indicated that PRP1 was composed of glucose, fructose, and arabinose in a molar ratio of 1:1.91:1.59 with a molecular weight of 440 kDa, whereas PRP2 was composed of arabinose, fructose, and galactose in a molar ratio of 1:1.39:1.18 with a molecular weight of 2.85 kDa. Compared with PRP2, PRP1 exerted stronger anticancer activity in vitro. Treatment with 5-30 μg/ml of PRP1 significantly inhibited the proliferation of HepG2 cells in vitro, and oral administration at the doses of 75-300 mg/kg also reduced the tumor growth in vivo. The miRNA expression patterns of human liver cancer cells HepG2 in vivo under PRP1 treatment were established, and microRNA-21 (miR-21) as the onco-miRNA was appreciably downregulated. PRP1 repressed the expression of miR-21, which directly targeted and suppressed PTEN (a negative regulator of the PI3K/Akt signaling cascade), and subsequently upregulated the expression of PTEN but downregulated the PI3K/AKT pathway, thereby promoting liver cancer cell apoptosis. These findings indicated that PRP1 inhibited the proliferation and induced the apoptosis of HepG2 mainly via inactivating the miR-21/PI3K/AKT pathway. Therefore, PRP1 could be used as a food supplement and candidate for the treatment of liver cancer.

Microalgae with Immunomodulatory Activities

Microalgae are photosynthetic microorganisms adapted to live in very different environments and showing an enormous biochemical and genetic diversity, thus representing an excellent source of new natural products with possible applications in several biotechnological sectors. Microalgae-derived compounds have shown several properties, such as anticancer, antimicrobial, anti-inflammatory, and immunomodulatory. In the last decade, compounds stimulating the immune system, both innate immune response and adaptive immune response, have been used to prevent and fight various pathologies, including cancer (cancer immunotherapy). In this review we report the microalgae that have been shown to possess immunomodulatory properties, the cells and the cellular mediators involved in the mechanisms of action and the experimental models used to test immunostimulatory activities. We also report information on fractions or pure compounds from microalgae identified as having immunostimulatory activity. Given the increasing interest in microalgae as new eco-friendly source of bioactive compounds, we also discuss their possible role as source of new classes of promising drugs to treat human pathologies.