Characterization of Bioactive Components in Edible Algae

Algae: A Robust Living Material Against Cancer

Cancer is the second leading cause of death worldwide. Its incidence has been increasing in recent years, and it is becoming a major threat to human health. Conventional cancer treatment strategies, including surgery, chemotherapy, and radiotherapy, have faced problems such as drug resistance, toxic side effects and unsatisfactory therapeutic efficacy. Therefore, better development and utilization of biomaterials can improve the specificity and efficacy of tumor therapy. Algae, as a novel living material, possesses good biocompatibility. Although some reviews have elucidated several algae-based biomaterials for cancer treatment, the majority of the literature has focused on a limited number of algae. As a result, there is currently a lack of comprehensive reviews on the subject of anticancer algae. This review aims to address this gap by conducting a thorough examination of algal species that show potential for anticancer activity. Furthermore, our review will also elucidate the engineering strategies of algae and discuss the challenges and prospects associated with their implementation.

Seaweed Sargassum aquifolium extract ameliorates cardiotoxicity induced by doxorubicin in rats

Doxorubicin (DOX) is a potent anticancer drug with adverse cardiotoxic effects. Alginates are multifunctional biopolymers and polyelectrolytes derived from the cell walls of brown seaweeds. They are nontoxic, biocompatible, and biodegradable, and hence, utilized in several biomedical and pharmaceutical applications. Here, we investigated the potential cardioprotective effect of thermally treated sodium alginate (TTSA), which was extracted and purified from the seaweed Sargassum aquifolium, in treating acute DOX cardiotoxicity and apoptotic pathways in rats. UV-visible spectroscopy, Fourier-transform infrared, and nuclear magnetic resonance (1H-NMR) spectroscopy techniques were used to characterize TTSA. CK-MB and AST levels in sera samples were determined. The expression levels of Erk-2 (MAPK-1) and iNOS genes were investigated by quantitative real-time polymerase chain reaction (qRT-PCR). The protein expression levels of Erk-2, anti-apoptotic p53, and caspase-3 were analyzed using western blotting and ELISA. For the in vivo studies, sixty rats were randomly divided equally into six groups and treated with DOX, followed by TTSA. We revealed that treatment with TTSA, which has low molecular weight and enhanced antioxidant properties, improved DOX-mediated cardiac dysfunction and alleviated DOX-induced myocardial apoptosis. Furthermore, TTSA exhibited a cardioprotective effect against DOX-induced cardiac toxicity, indicated by the increased expression of MAPK-1 (Erk2) and iNOS genes, which are implicated in the adaptive responses regulating DOX-induced myocardial damage. Moreover, TTSA significantly (p < 0.05) suppressed caspase-3 and upregulated anti-apoptotic protein p53 expression. TTSA also rebalanced the cardiomyocyte redox potential by significantly (p < 0.05) increasing the levels of endogenous antioxidant enzymes, including catalase and superoxide dismutase. Our findings suggest that TTSA, particularly at a dose of 400 mg/kg b.w., is a potential prophylactic supplement for treating acute DOX-linked cardiotoxicity.

The possible role of the seaweed Sargassum vulgare as a promising functional food ingredient minimizing aspartame-associated toxicity in rats

Thirty-two male Wistar albino rats were chosen to test the possible protective role of antioxidants of the edible seaweed Sargassum vulgare as a functional food additive to alleviate oxidative stress and toxicity associated with consumption of the artificial sweetener 'aspartame (ASP)'. Biochemical and spleen histopathological analyses of the orally ASP-administrated rats, at a dose of 500 mg/kg for one week daily, showed different apoptotic and inflammatory patterns. Rats treated with ASP and then supplemented orally with the S. vulgare-MeOH extract, at a dose of 150 mg/kg for three consecutive weeks daily, showed significant positive reactions in all investigated assays related to ASP consumption. The protective and immune-stimulant efficacy of S. vulgare-MeOH extract, inferred from combating oxidative stress-induced lipid peroxidation, modulating the low levels of the endogenous antioxidant enzymes superoxide dismutase (SOD) and catalase (CAT) and of the thyroid hormones T3 and T4, attenuating the elevated levels of apoptotic CASP-3 and inflammatory biomarkers TNF-α and IL-6, as well as heat shock proteins (Hsp70), can be most likely ascribed to the synergistic effect of its potent antioxidant phenolics (mainly gallic, ferulic, salicylic, and chlorogenic, and p-coumaric acids) and flavonoids (rutin, kaempferol, and hesperidin). Mechanism of action of these natural antioxidants was discussed.

Chondrus crispus treated with ultrasound as a polysaccharides source with improved antitumoral potential

Ultrasound-assisted extraction was used to recover gelling biopolymers and antioxidant compounds from Chondrus crispus with improved biological potential. The optimal processing conditions were evaluated using a Box-Behnken design, and the impact on the biological and thermo-rheological properties of the carrageenan fraction and on the bioactive features of the soluble extracts were studied. The optimum extraction parameters were defined by extraction time of ~34.7 min; solid liquid ratio of ~2.1 g/100 g and ultrasound amplitude of ~79.0% with a maximum power of 1130 W. The dependent variables exhibited maximum carrageenan yields (44.3%) and viscoelastic modulus (925.9 Pa) with the lowest gelling temperatures (38.7 °C) as well as maximum content of the extract in protein (22.4 mg/g), gallic acid (13.4 mg/g) and Trolox equivalents antioxidant capacity (182.4 mg TEAC/g). Tested hybrid carrageenans exhibited promising biological activities (% of growth inhibition around 91% for four human cancer cellular lines: A549; A2780; HeLa 229; HT-29).

Benefits and Drawbacks of Ultrasound-Assisted Extraction for the Recovery of Bioactive Compounds from Marine Algae

The increase in life expectancy has led to the appearance of chronic diseases and interest in healthy aging, in turn promoting a growing interest in bioactive compounds (BCs) and functional ingredients. There are certain foods or products rich in functional ingredients, and algae are one of them. Algae consumption has been nominal in Europe until now. However, in recent years, it has grown significantly, partly due to globalization and the adoption of new food trends. With the aim of obtaining BCs from foods, multiple methods have been proposed, ranging from conventional ones, such as maceration or Soxhlet extraction, to more innovative methods, e.g., ultrasound-assisted extraction (UAE). UAE constitutes a novel method, belonging to so-called green chemistry, that enables the extraction of BCs requiring lower amounts of solvent and energy costs, preserving the integrity of such molecules. In recent years, this method has been often used for the extraction of different BCs from a wide range of algae, especially polysaccharides, such as carrageenans and alginate; pigments, including fucoxanthin, chlorophylls, or β-carotene; and phenolic compounds, among others. In this way, the application of UAE to marine algae is an efficient and sustainable strategy to pursue their deep characterization as a new source of BCs, especially suitable for vegetarian and vegan diets.

Empowering blue economy: From underrated ecosystem to sustainable industry

With increasing demand for resources to achieve global food-water-energy nexus and rapid decline in land-based sources, oceans represent both solution and boost to sustainable environment and economy. In addition to fundamental part of earth's ecosystem for uncatalogued diversity of life, oceans are undervalued economy powerhouse with gross marine product value. With sustainable management of existing assets including shipping, transportation, manufacturing, fisheries, tourism and exploration of new business like marine biotechnology and renewable energy, the ocean or blue economy has potential to fulfill sustainable development goals (SDG). In spite of recognition of blue economy as a new economic frontier, investments by existing industries and emergence of new ones are limited and less known, hence require more in depth attention and scientific understanding. In the present study, authors present a systematic comparative assessment of blue economy sectors with distinct challenges and strategies to be further explored and implemented for industrial deployment. The conceptualization of integrated routes of bio(economy) by the current study can act as gateway for key stakeholders, i.e. governance, bluepreneurs (scientists and industries) to prioritize technologies for sustainable applications of marine resources.

Eco-friendly extraction of Mastocarpus stellatus carrageenan for the synthesis of gold nanoparticles with improved biological activity

Carrageenan was extracted from Mastocarpus stellatus using hot water extraction under atmospheric and pressurized conditions. The influence of heating temperature during a non-isothermal heating profile up to temperatures in the range 70-190 °C was studied to evaluate the extraction yields and properties of the carrageenan fraction. Under the selected conditions (130 °C), extracted carrageenan (CMs) was used for the green synthesis of gold nanoparticles (AuNPs). After the optimization of the reaction conditions, the synthesized gold nanoparticles (Au@CMs) were characterized by UV-Vis spectroscopy, Z potential measurements, electron microscopy, and X-ray diffraction analysis, which confirmed the formation of spherical, polycrystalline, and negatively charged nanoparticles with a mean diameter of 14.3 ± 2.1 nm. The study conducted by scanning transmission electron microscopy, energy dispersive X-ray analysis and mapping confirmed the presence of carrageenan stabilizing AuNPs. Finally, Fourier transformed infrared spectroscopy was performed to analyze the functional groups of CMs involved in the reduction and stabilization of AuNPs. The selective cytotoxicity and the antioxidant activity of the Au@CMs were evaluated in different cell lines and compared to the CMs. Au@CMs showed an improved antioxidant capacity in cells under oxidative stress and the induction of apoptosis in a monocytic cell line, while no antitumor effect was observed in a lung endothelial cell line.

The possible role of the seaweed Ulva fasciata on ameliorating hyperthyroidism-associated heart inflammations in a rat model

Cardiovascular diseases are key complications primarily associated with hyperthyroidism disorders. The present study sought to ameliorate hyperthyroidism-mediated cardiovascular inflammations and related oxidative stress paradigms in experimental rats using the broadly distributed green seaweed Ulva fasciata. Forty-eight adult male albino rats were recruited and randomly classified into six groups. Hyperthyroidism was stimulated using L-thyroxine sodium at a dose of 100 μg/kg i.p. for 3 weeks daily. Further, 200 mg/kg b.wt. concentration of the U. fasciata methanolic (U. fasciata-MeOH) extract was the recommended dose and administrated orally to the hyperthyroid rats. The standard commercial drug "propranolol hydrochloride" was also tested at a dose of 10 mg/kg i.p. to compare the findings obtained from the seaweed extract. A combined treatment with the U. fasciata-MeOH extract and propranolol hydrochloride was also assessed. Our results implied that the treatment of hyperthyroid rats with the U. fasciata-MeOH extract significantly reduced serum levels of the thyroid hormones T3 and T4, proinflammatory cytokines (TNF-α, MPO, and CRP), triglycerides and total cholesterol, as well as the cardiac biomarkers CK-MB, LDH, and troponin to thresholds close to those of the standard drug. In addition, levels of high-density lipoprotein cholesterol (HDL-C) and interleukin 10 (IL-10) were significantly upregulated. Hyperthyroid rats only treated with propranolol hydrochloride, or with a combination of the drug and the seaweed extract, conferred the same observations. Histopathological architecture boosted our interesting findings where the myocardium tissues in hyperthyroid rats, administrated the U. fasciata-MeOH extract or/and propranolol hydrochloride, exhibited more or less a normal structure as the control, reflecting the potential cardiovascular recovery exerted by this seaweed extract. In vitro DPPH, ABTS, and FRAP antioxidant assays of the U. fasciata-MeOH extract showed an outstanding ROS-scavenging potential. HPLC analysis of the U. fasciata-MeOH extract unraveled an inestimable valuable array of phenolics (mainly p-coumaric, gallic, ferulic, chlorogenic, and syringic acids) and flavonoids (hesperidin, kaempferol, catechin, quercetin, and rutin). Conclusively, the seaweed U. fasciata is a profitable source of antioxidant polyphenolics characterized by having a pharmaceutical potential against hyperthyroidism-linked cardiovascular inflammations and oxidative stress patterns due to their substantial free radical quenching properties, and also via regulating the signalling pathways of the proinflammatory, lipid profile, and cardiac biomarkers.