Anticancer effects of different seaweeds on human colon and breast cancers

Evaluation of antioxidant properties and cytotoxicity of brown algae (nizamuddinia zanardinii) in uterine (hela) and pancreatic cancer cell lines (paca-2)

INTRODUCTION

Pancreatic cancer and cervical cancer are among the most common cancers. Brown algae have anti-inflammatory, anti-cancer, anti-fungal, antioxidant, and immune-boosting properties. This study investigated the antioxidant properties and the effect of brown algae extract on pancreatic and uterine cancer cells.

MATERIALS AND METHODS

In this study, Cervical (Hela) and pancreas (Paca-2) cancer cell lines were examined. The algae materials were extracted by sequential maceration method and amount of fucoxanthin content in the sample was determined by using High Performance Liquid Chromatography (HPLC) system. The cytotoxic effect of different concentrations of brown algae was measured by the MTT assay. All statistical calculations for comparing IC50 were analyzed using Graph Pad Prism software.

RESULTS

the algal sample contained an average of 102.52 ± 0.12 μg of fucoxanthin per 100 g. IC50 for 2, 2-diphenyl-1-picrylhydrazyl (DPPH) and hydrogen peroxide free radical scavenging activity for methanolic extract was 2.02 and 11.98 ± 0.13 respectively. Brown algae in all fractions inhibited cell growth and survival. In Hela cell lines, the methanolic extract was the most effective inhibitor, while in Paca cell lines, hexane and methanolic extracts were particularly potent. The methanolic extract was more toxic than other fractions on Hela and Paca cell lines.

CONCLUSION

This study highlights brown algae extracts strong anticancer effects on uterine and pancreatic cancer cells, suggesting its potential as a natural anticancer drug. Different fractions of the extract showed superior apoptotic and cytotoxic effects, with higher concentrations leading to increased apoptotic effects and reduced survival rates of cancer cells.

Tropical Seaweeds as a Sustainable Resource Towards Circular Bioeconomy: Insights and Way Forward

Seaweeds are photosynthetic marine macroalgae known for their rapid biomass growth and their significant contributions to global food and feed production. Seaweeds play a crucial role in mitigating various environmental issues, including greenhouse gases, ocean acidification, hypoxia, and eutrophication. Tropical seaweeds are typically found in tropical and subtropical coastal zones with warmer water temperatures and abundant sunlight. These tropical seaweeds are rich sources of proteins, vitamins, minerals, fibers, polysaccharides, and bioactive compounds, contributing to their health-promoting properties and their diverse applications across a range of industries. The productivity, cultivability, nutritional quality, and edibility of tropical seaweeds have been well-documented. This review article begins with an introduction to the growth conditions of selected tropical seaweeds. Subsequently, the multifunctional properties of tropical seaweeds including antioxidant and anti-inflammatory, anti-coagulant, anti-carcinogenic and anti-proliferative, anti-viral, therapeutic and preventive properties were comprehensively evaluated. The potential application of tropical seaweeds as functional foods and feeds, as well as their contributions to sustainable cosmetics, bioenergy, and biofertilizer production were also highlighted. This review serves as a valuable resource for researchers involved in seaweed farming as it provides current knowledge and insights into the cultivation and utilization of seaweeds.

Antioxidant and chemotherapeutic efficacies of seaweed-derived phlorotannins in cancer treatment: A review regarding novel anticancer drugs

The ineffectiveness of traditional cancer therapies due to drug resistance, nontargeted delivery, and chemotherapy-associated adverse side effects has shifted attention to bioactive phytochemicals. Consequently, research efforts toward screening and identification of natural compounds with anticancer properties have increased in recent years. Marine seaweed-derived bioactive compounds, such as polyphenolic compounds, have exhibited anticancer properties. Phlorotannins (PTs), a major group of seaweed-derived polyphenolic compounds, have emerged as powerful chemopreventive and chemoprotective compounds, regulating apoptotic cell death pathways both in vitro and in vivo. In this context, this review focuses on the anticancer activity of polyphenols isolated from brown algae, with a special reference to PTs. Furthermore, we highlight the antioxidant effects of PTs and discuss how they can impact cell survival and tumor development and progression. Moreover, we discussed the potential therapeutic application of PTs as anticancer agents, having molecular mechanisms involving oxidative stress reduction. We have also discussed patents or patent applications that apply PTs as major components of antioxidant and antitumor products. With this review, researcher may gain new insights into the potential novel role of PTs, as well as uncover a novel cancer-prevention mechanism and improve human health.

The Brown Alga Bifurcaria bifurcata Presents an Anthelmintic Activity on All Developmental Stages of the Parasitic Nematode Heligmosomoides polygyrus bakeri

The current control of gastrointestinal (GI) parasitic nematodes mainly relies on the widespread use of anthelmintics, which has inevitably led to resistance. Therefore, there is an urgent need to find new sources of antiparasitic compounds. Macroalgae represent a rich source of active molecules and are widely described as having medicinal properties. In the present study, we investigated the potential anthelmintic activity of aqueous extracts from three species of algae (Bifurcaria bifurcata, Grateloupia turuturu and Osmundea pinnatifida) on the murine parasite Heligmosomoides polygyrus bakeri. Using a set of complementary in vitro tests, including larval development assays, egg hatching tests and nematicidal activity assays on larvae and adults, we report the nematicidal activity of aqueous extracts of B. bifurcata. In addition, aqueous extract fractionation using liquid/liquid partitioning with a solvent of increasing polarity was performed in order to identify the groups of active molecules underlying the anthelmintic activity. Non-polar extracts (heptane, ethyl acetate) demonstrated high anthelmintic potential, highlighting the role of non-polar metabolites such as terpenes. Here, we highlight the strong anthelmintic potential of the brown alga B. bifurcata on a mouse model of GI parasites, thus confirming the strong interest in algae as natural alternatives for the control of parasitic nematodes.

Efficacy of Synthesized Cubic Spirulina Platensis Photosensitizer in Anticancer Photodynamic Therapy: An in vitro study

Photodynamic therapy (PDT) is becoming increasingly popular in cancer management. Photosensitizers derived from natural sources can offer additional health benefits and play a crucial role in enhancing the efficacy of PDT in cancer treatment. We herein synthesized a cubic form of spirulina platensis (SP) and compared its anticancer-PDT efficacy with the naturally-occurring microhelical SP (MSP) and phycocyanin (Pc) against a tongue cancer cell-line and fibroblast cells. Cubic SP (CSP) was synthesized and characterized using standard analyses. CAL-27 and HGF cell-lines were incubated at different concentrations with each photosensitizer and were irradiated with 635 nm diode-laser. The viability, cellular-uptake, apoptosis and oxidative stress potential were quantitatively analyzed and statistically compared at P<0.05. Our results demonstrated that all three photosensitizers were non-toxic to normal cells before laser irradiation. In CAL-27, viability significantly decreased after PDT in all photosensitizer groups (P<0.05). Whereas, in HGF, Pc exhibited phototoxicity after laser irradiation (P=0.032). Cell-death was mainly apoptotic in Pc and CSP, but necrotic in MSP. Cellular-uptake was significantly higher in Pc, but was similar in MSP and CSP. Increase in reactive oxygen species was significantly higher in the Pc group compared to both SPs (P<0.05). We concluded that both SPs were safe and efficient photosensitizers for anticancer-PDT. CSP exhibited predominant and significant apoptotic death in CAL-27 and HGF cell-lines, while MSP mainly induced necrotic cell death. Despite the good photosensitizing performance of Pc, its use in higher concentrations should be considered with caution, due to the reduced viability that occurred following its use in PDT.

Naturally Occurring Organohalogen Compounds-A Comprehensive Review

The present volume is the third in a trilogy that documents naturally occurring organohalogen compounds, bringing the total number-from fewer than 25 in 1968-to approximately 8000 compounds to date. Nearly all of these natural products contain chlorine or bromine, with a few containing iodine and, fewer still, fluorine. Produced by ubiquitous marine (algae, sponges, corals, bryozoa, nudibranchs, fungi, bacteria) and terrestrial organisms (plants, fungi, bacteria, insects, higher animals) and universal abiotic processes (volcanos, forest fires, geothermal events), organohalogens pervade the global ecosystem. Newly identified extraterrestrial sources are also documented. In addition to chemical structures, biological activity, biohalogenation, biodegradation, natural function, and future outlook are presented.

Antitumor immunity and therapeutic properties of marine seaweeds-derived extracts in the treatment of cancer

Marine seaweeds are important sources of drugs with several pharmacological characteristics. The present study aims to evaluate the antitumor and antitumor immunological potentials of the extracts from the brown alga Padinapavonica and the red alga Janiarubens, inhibiting the Egyptian marine coasts. Hep-G2 cell lines were used for assessment of the antitumor efficacy of Padinapavonica and Janiarubens extracts in vitro, while Ehrlich ascites carcinoma (EAC) cells were applied to gain more antitumor immunity and antitumor insights of P.pavonica and J.rubens extracts in vivo. In vitro antitumor potentials of P.pavonica and J.rubens extracts were analyzed against human liver cancer Hep-G2 cells by MTT and trypan blue exclusion assays. In vivo antitumor immunological potentials of P.pavonica and J.rubens extracts at low, high, and prophylactic doses were analyzed by blood counting and flow cytometry in mice challenged with Ehrlich ascites carcinoma (EAC) cells. In vitro results revealed that P.pavonica and J.rubens extracts caused significant decreases in the number and viability of Hep-G2 cells in a dose-dependent manner as compared to untreated Hep-G2 cells or Cisplatin^®-treated Hep-G2 cells. In vivo findings showed that P.pavonica and J.rubens extracts at low, high, and prophylactic doses significantly reduced the number and viability of EAC tumor cells accompanied by increases in EAC apoptosis compared to naïve EAC mouse. Additionally, P.pavonica and J.rubens extracts at low and prophylactic doses remarkably increased both the total WBC count and the relative numbers of lymphocytes and decreased the relative numbers of neutrophils and monocytes. Flow cytometric analysis showed that P.pavonica and J.rubens extracts at the treatment and the prophylactic doses resulted in a significant increase in the phenotypic expressions of CD4⁺ T, CD8⁺ T, and CD335 cells compared to naïve EAC mouse. Overall, both extracts P.pavonica and J.rubens possess potential antitumor and antitumor immunological effects with less toxicity, opening new approaches for further studies of the chemical and biological mechanisms behind these effects.

Effectiveness of Fucoidan on Supplemental Therapy in Cancer Patients: A Systematic Review

Purpose: Fucoidan is a dietary supplement which is commonly used by cancer patients. However, despite evidence of positive effects in cell culture environments, there are currently no clinical guidelines for supplementary use of fucoidan in cancer patients. This study aims to evaluate the effectiveness of fucoidan supplemental use. Methods: A systematic literature search was conducted using databases including Cochrane Library, JBI, PubMed, Embase, and CINAHL. All original studies on fucoidan for supplemental use in cancer patients were included. The search was made in databases without time restriction. The outcomes included disease progression status, inflammatory markers, nutritional status, adverse effects, and quality of life. The appraisal tool used was JBI-MAStARI. Results: Four studies were included: One randomized controlled trial and three quasi-experimental studies. Meta-analysis was not applied due to the heterogeneity of measurement tools. Overall sample size was 118. Most participants were metastatic colorectal and gastric cancer patients. Two studies revealed a significantly longer survival time and chemotherapy treatment periods with fucoidan use. Positive but insignificant effects of disease control rate, inflammatory markers, nutrition status, fatigue, and financial difficulty were shown in those using fucoidan. Conclusions: The results of this systematic review indicate that the effects of fucoidan were inconsistent with clinical outcomes in metastatic or recurrent cancer patients. Only four studies were included, and heterogeneity in methodologies and relatively small sample sizes limited the research consensus. Although cause and effect between fucoidan and the survival time, disease control or adverse effects could not be confirmed, this study includes the most research on fucoidan in humans.

The Red Seaweed Grateloupia turuturu Prevents Epidermal Dysplasia in HPV16-Transgenic Mice

The role of dietary profiles in promoting or reducing the risk of multiple types of cancer is increasingly clear, driving the search for balanced foods and nutraceuticals. The red seaweed Grateloupia turuturu has been used as human food showing a balanced nutritional profile. This study aims to test in vivo chemopreventive effects of G. turuturu against cutaneous pre-malignant lesions in transgenic mice for the human papillomavirus type 16 (HPV16). Forty-four female HPV^+/− or HPV^−/− mice received a standard diet or were supplemented with 10% G. turuturu for 22 consecutive days. Cutaneous lesions (ear and chest skin) were identified histologically. Complementarily, the weights and histology of internal organs as well as blood biochemical and DNA integrity parameters were also assessed. G. turuturu consistently reduced the incidence of epidermal dysplasia induced by HPV16 on both cutaneous sites. Moreover, biochemical, DNA integrity and histological analyses confirmed G. turuturu edibility as no signs of toxicity were found. Dietary supplementation with G. turuturu is an effective and safe chemopreventive strategy in this model.

The Toxic Mechanism of Gliotoxins and Biosynthetic Strategies for Toxicity Prevention

Gliotoxin is a kind of epipolythiodioxopiperazine derived from different fungi that is characterized by a disulfide bridge. Gliotoxins can be biosynthesized by a gli gene cluster and regulated by a positive GliZ regulator. Gliotoxins show cytotoxic effects via the suppression the function of macrophage immune function, inflammation, antiangiogenesis, DNA damage by ROS production, peroxide damage by the inhibition of various enzymes, and apoptosis through different signal pathways. In the other hand, gliotoxins can also be beneficial with different doses. Low doses of gliotoxin can be used as an antioxidant, in the diagnosis and treatment of HIV, and as an anti-tumor agent in the future. Gliotoxins have also been used in the control of plant pathogens, including Pythium ultimum and Sclerotinia sclerotiorum. Thus, it is important to elucidate the toxic mechanism of gliotoxins. The toxic mechanism of gliotoxins and biosynthetic strategies to reduce the toxicity of gliotoxins and their producing strains are summarized in this review.

Marine Health-Promoting Compounds: Recent Trends for Their Characterization and Human Applications

Seaweeds represent a rich source of biologically active compounds with several applications, especially in the food, cosmetics, and medical fields. The beneficial effects of marine compounds on health have been increasingly explored, making them an excellent choice for the design of functional foods. When studying marine compounds, several aspects must be considered: extraction, identification and quantification methods, purification steps, and processes to increase their stability. Advanced green techniques have been used to extract these valuable compounds, and chromatographic methods have been developed to identify and quantify them. However, apart from the beneficial effects of seaweeds for human health, these natural sources of bioactive compounds can also accumulate undesirable toxic elements with potential health risks. Applying purification techniques of extracts from seaweeds may mitigate the amount of excessive toxic components, ensuring healthy and safer products for commercialization. Furthermore, limitations such as stability and bioavailability problems, chemical degradation reactions during storage, and sensitivity to oxidation and photo-oxidation, need to be overcome using, for example, nanoencapsulation techniques. Here we summarize recent advances in all steps of marine products identification and purification and highlight selected human applications, including food and feed applications, cosmetic, human health, and fertilizers, among others.

The effect of photodynamic therapy on head and neck squamous cell carcinoma cell lines using spirulina platensis with different laser energy densities

BACKGROUND

Considering the anti-cancer properties of spirulina platensis (S. platensis), we aimed to investigate the effectiveness of this algae as a novel natural photosensitizer for photodynamic therapy (PDT) against oral and hypopharyngeal cancer cells. The appropriate laser energy density to apply during PDT was also determined.

METHODS AND MATERIALS

CAL-27, FaDu and HGF cell lines were exposed to S. platensis with concentrations of 0.3 g/l and 0.6 g/l and were irradiated with 635 nm diode laser using 2, 4, 12, and 24 J/cm² energy densities with constant power. MTT assay was performed to investigate cell viability and cytotoxicity after 24 h. The results were analyzed using two-way ANOVA and post hoc Tukey tests (P-value<0.05).

RESULTS

survival rate in CAL-27 (P-Value<0.001) and FaDu (P-Value<0.001) cell lines were significantly different following irradiation with various laser energy densities. Different concentrations of S. platensis had no significant effect on the viability of CAL-27 cells (P-Value=0.158) and FaDu cells (P-Value=0.072) and showed no significant cytotoxicity against HGF cells, with or without laser.

CONCLUSION

S. platensis could be considered as a novel safe and effective natural photosensitizer for cancer PDT with no cytotoxic effect on normal cells. When combined with laser using appropriate energy densities, it has the ability to induce death in oral and hypopharyngeal cancer cell lines.

Anticancer Effects of Seaweed-Derived Bioactive Compounds

Cancer remains a major life-threatening disease worldwide. The development of anticancer drugs using natural products obtained from marine organisms has been proposed as an alternative approach. Seaweeds are the mainstay of marine ecosystems; therefore, they are highly enriched with diverse bioactive compounds. In the past decade, a vast number of natural compounds, such as polysaccharides, polyphenols, carotenoids, and terpenoids, have been isolated from seaweeds. Seaweeds have bioactive compounds that show cytotoxicity in various cancer cell lines. These compounds prevent tumor growth by inducing apoptotic cell death and arrest growth by interfering with different kinases and cell cycle pathways. This review discussed the anticancer properties of various bioactive compounds isolated from different types of seaweeds and their therapeutic potential against cancers.

Identified Seaweed Compound Diphenylmethane Serves as an Efflux Pump Inhibitor in Drug-Resistant Escherichia coli

Drug efflux pumps are one of the major elements used by antibiotic-resistant bacteria. Efflux pump inhibitors (EPIs) are potential therapeutic agents for adjunctive therapy, which can restore the activity of antibiotics that are no longer effective against pathogens. This study evaluated the seaweed compound diphenylmethane (DPM) for its EPI activity. The IC₅₀ and modulation results showed that DPM has no antibacterial activity but can potentiate the activity of antibiotics against drug-resistant E. coli. Time-kill studies reported that a combination of DPM and erythromycin exhibited greater inhibitory activity against drug-resistant Escherichia coli. Dye accumulation and dye efflux studies using Hoechst 33342 and ethidium bromide showed that the addition of DPM significantly increased dye accumulation and reduced dye efflux in drug-resistant E. coli, suggesting its interference with dye translocation by an efflux pump. Using MALDI-TOF, it was observed that the addition of DPM could continuously reduce antibiotic efflux in drug-resistant E. coli. Additionally, DPM did not seem to damage the E. coli membranes, and the cell toxicity test showed that it features mild human-cell toxicity. In conclusion, these findings showed that DPM could serve as a potential EPI for drug-resistant E. coli.

Dieckol: a brown algal phlorotannin with biological potential

Dieckol [C36H22O18], is a naturally occurring phlorotannin found in some brown algal species. Dieckol is gaining more attention in the scientific community for its potential biological activities. It has been exhibited a broad spectrum of therapeutic functions including anti-bacterial, anti-cancer, anti-oxidant, anti-aging, anti-diabetic, neuroprotective, and other medicinal applications. Distinct emphasis has been given to extraction, purification, and biomedical applications of dieckol. This critical review comprises of in vitro, in vivo, and in silico biological properties of dieckol. An attempt has been made to evaluate the effectiveness, therapeutical application, and mechanism of dieckol against various diseases. The pharmacological significance, current status and the dosage of multifunctional dieckol and its mechanisms have been discussed in this review. Dieckol plays an important role in apoptosis induction via inhibiting the PI3K, AKT, mTOR and FAK signaling molecules. Dieckol remarkably inhibited the lipid accumulation in high fat diet induced animal models. Dieckol, a multifaceted compound will be beneficial in attenuating the action of various diseases and it could be a potential pharmaceutical and nutraceutical compound. Therefore, the combined effects of dieckol with existing drugs and natural compounds will be studied in future to optimize its benefits. Besides limited information on the toxicological action and dosage administration of dieckol on the human was reported to date. Overall, dieckol is a prospective health-promoting compound for the development of a novel drug against numerous diseases.

Metabolic regulation mechanism of fucoidan via intestinal microecology in diseases

The intestinal microecology is an extremely complex ecosystem consisting of gut microbiota, intestinal mucosa and the intestinal immune system. The intestinal microecology performs several important functions and is considered to be an essential 'organ' because it plays an important role in regulating human metabolism. Fucoidan contains a large amount of fucose and galactose residues, as well as various other neutral and acidic monosaccharides. Fucoidan particularly effects tumors, inflammatory bowel disease, diabetes and obesity by repairing intestinal mucosal damage and improving the intestinal microecological environment. It has been proposed that fucoidan could be used as a prebiotic agent for pharmaceutical and functional foods. In this review, we elucidate the potential mechanisms of the metabolic regulation of fucoidan with respect to the intestinal microecology of diseases. © 2021 Society of Chemical Industry.

Phytochemical screening, antioxidant potential, and cytotoxic effects of different extracts of red algae (Laurencia snyderiae) on HT29 cells

Background and purpose

Marine algae are potential renewable and sustainable sources of bioactive natural products which can be utilized in nutraceutical and pharmaceutical industries.

Experimental approach

Different extracts (methanol, chloroform, and ethyl acetate) of red algae, Laurencia snyderiae, was evaluated for their antioxidant potential, with various antioxidant assessment assays, cytotoxic properties (using MTT colorimetric assay), and phytochemical constituents (total phenolic and flavonoid contents). The GC-MS analyses of the algal methanolic extract and its apoptotic effects on the human colon carcinoma cell line (HT29) were also investigated.

Findings/Results

The total phenolic content in the methanol, chloroform, and ethyl acetate extracts of L. snyderiae was 3.6 ± 0.12, 3.2 ± 0.41, and 3.3 ± 0.35 μg/mg of gallic acid, respectively. Among different algae extracts, chloroform extract showed significantly chelating ability (IC₅₀ = 0.027 mg/mL) and reducing power activity (IC₅₀ = 0.082 mg/mL), while the highest DPPH scavenging activity (IC₅₀ = 0.058 mg/mL) exhibited in the methanol extract compared to the other extracts. The methanolic extract was found to have a higher cytotoxicity effect on colon carcinoma cells with IC₅₀ 70.2 μg/mL. The viability of the cancer cells was increased with the decrease in the concentration in different extracts. GC-MS analysis of the algal methanolic extract revealed the presence of active antitumor constituents and apoptosis-based cytotoxicity against colon cancer cells through the DNA damage was also confirmed.

Conclusion and implications

Based on these results, the red algae L. snyderiae possesses potent bioactive constituents and can use as additional resources as a natural antioxidant and antitumor agent in the pharmaceutical and nutraceutical area.

Integrated algal and oil palm biorefinery as a model system for bioenergy co-generation with bioproducts and biopharmaceuticals

BACKGROUND

There has been a greater call for greener and eco-friendly processes and bioproducts to meet the 2030's core agenda on 17 global sustainable development goals. The challenge lies in incorporating systems thinking with a comprehensive worldview as a guiding principle to develop the economy, whilst taking cognisance of the need to safeguard the environment, and to embrace the socio-cultural diversity dimension as an equal component. Any discussion on climate change, destruction of eco-system and habitat for wildlife, poverty and starvation, and the spread of infectious diseases, must be addressed together with the emphasis on the development of cleaner energy, air and water, better management of resources and biodiversity, improved agro-practices for food production and distribution, and affordable health care, as the outcomes and key performance indicators to be evaluated. Strict regulation, monitoring and enforcement to minimize emission, pollution and wastage must also be put in place.

CONCLUSION

This review article focuses on the research and development efforts to achieve sustainable bioenergy production, environmental remediation, and transformation of agro-materials into value-added bioproducts through the integrated algal and oil palm biorefinery. Recent development in microalgal research with nanotechnology as anti-cancer and antimicrobial agents and for biopharmaceutical applications are discussed. The life-cycle analysis in the context of palm oil mill processes is evaluated. The way forward from this integrated biorefinery concept is to strive for inclusive development strategies, and to address the immediate and pressing problems facing the Planet and the People, whilst still reaping the Profit.

Microalgal extract from thermotolerant Coelastrella sp. F50 retards the liver tumor progression by targeting hepatic cancer stem cells

Microalgae extracts have shown antitumor activities. However, the antitumor mechanism of them is not yet completely clear, especially the effect on cancer stem cells (CSCs). This study aimed to elucidate the antitumor activity and mechanism of microalgal extract from thermotolerant Coelastrella sp. F50 (F50) in hepatocellular carcinoma (HCC). Oncogenic behaviors were analyzed using cell proliferation, colony formation, invasion, sphere formation, and side population cells (SPCs) assays in HCC cells after F50 treatment. The molecular mechanism was further studied by quantitative real-time PCR, immunoblot, and immunofluorescence analyses. The chemopreventive efficacy of F50 was evaluated in rat orthotopic hepatoma, and the hepatic pathologies were investigated by immunohistochemical, immunoblot, and immunofluorescence analyses. F50 specifically suppressed hepatic CSCs (tumor spheres, drug efflux, CD133/ABCG2 CSCs markers) with no cytotoxicity in vitro. In the animal experiments, prophylactic F50 administration significantly attenuated tumor progression and improved liver function in HCC-bearing rats. In the mechanistic analysis, F50 potentially inhibited cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE₂ ) axis in HCC cells and rat hepatoma, and exogenous PGE₂ restored CSCs properties in F50-treated HCC cells. In summary, F50 extract inhibits hepatic CSCs by COX-2/PGE₂ downregulation and may facilitate a novel phytotherapy for HCC prevention.

Effects of brown seaweeds on postprandial glucose, insulin and appetite in humans - A randomized, 3-way, blinded, cross-over meal study

BACKGROUND & AIMS

Seaweed including brown seaweeds with rich bioactive components may be efficacious for a glycaemic management strategy and appetite control. We investigated the effects of two brown edible seaweeds, Laminaria digitata (LD) and Undaria pinnatifida (UP), on postprandial glucose metabolism and appetite following a starch load in a human meal study.

METHODS

Twenty healthy subjects were enrolled in a randomized, 3-way, blinded cross-over trial. The study was registered under ClinicalTrials.gov Identifier no. NCT00123456. At each test day, the subjects received one of three meals comprising 30 g of starch with 5 g of LD or UP or an energy-adjusted control meal containing pea protein. Fasting and postprandial blood glucose, insulin, C-peptide and glucagon-like peptide-1 (GLP-1) concentrations were measured. Subjective appetite sensations were scored using visual analogue scales (VAS).

RESULTS

Linear mixed model (LMM) analysis showed a lower blood glucose, insulin and C-peptide response following the intake of LD and UP, after correction for body weight. Participants weighing ≤ 63 kg had a reduced glucose response compared to control meal between 40 and 90 min both following LD and UP meals. Furthermore, LMM analysis for C-peptide showed a significantly lower response after intake of LD. Compared to the control meal, GLP-1 response was higher after the LD meal, both before and after the body weight adjustment. The VAS scores showed a decreased appetite sensation after intake of the seaweeds. Ad-libitum food intake was not different three hours after the seaweed meals compared to control.

CONCLUSIONS

Concomitant ingestion of brown seaweeds may help improving postprandial glycaemic and appetite control in healthy and normal weight adults, depending on the dose per body weight.

CLINICAL TRIAL REGISTRY NUMBER

Clinicaltrials.gov (ID# NCT02608372).

Cytotoxicity of Seaweed Compounds, Alone or Combined to Reference Drugs, against Breast Cell Lines Cultured in 2D and 3D

Seaweed bioactive compounds have shown anticancer activities in in vitro and in vivo studies. However, tests remain limited, with conflicting results, and effects in combination with anticancer drugs are even scarcer. Here, the cytotoxic effects of five seaweed compounds (astaxanthin, fucoidan, fucosterol, laminarin, and phloroglucinol) were tested alone and in combination with anticancer drugs (cisplatin-Cis; and doxorubicin-Dox), in breast cell lines (three breast cancer (BC) subtypes and one non-tumoral). The combinations revealed situations where seaweed compounds presented potentiation or inhibition of the drugs' cytotoxicity, without a specific pattern, varying according to the cell line, concentration used for the combination, and drug. Fucosterol was the most promising compound, since: (i) it alone had the highest cytotoxicity at low concentrations against the BC lines without affecting the non-tumoral line; and (ii) in combination (at non-cytotoxic concentration), it potentiated Dox cytotoxicity in the triple-negative BC cell line. Using a comparative approach, monolayer versus 3D cultures, further investigation assessed effects on cell viability and proliferation, morphology, and immunocytochemistry targets. The cytotoxic and antiproliferative effects in monolayer were not observed in 3D, corroborating that cells in 3D culture are more resistant to treatments, and reinforcing the use of more complex models for drug screening and a multi-approach that should include histological and ICC analysis.

Four selected commercial seaweeds: biologically active compounds, antioxidant and cytotoxic properties

The aim of this research work was to study the chemical characterisation, antioxidant and cytotoxic activity of ethanolic extracts of four commercial algae species Arame, Kombu, Hijiki and Wakame. The highest scavenging activity has been observed in Arame extract. Antioxidant potential of all extracts was in correlation with total phenol content (Arame extract: 319.15 ± 0.56 mg GAE/g d.w) and it was not in correlation with total carotenoids content (Wakame: 75.15 ± 0.20 mg/g). Polyphenols were quantified using LC-MS/MS technique. Baicalein and amentoflavone were identified in higher amount in relation to other phenols. Intracellular antioxidant activity and cytotoxicity of algae extracts were evaluated on the human prostate cancer cell line PC3. Although presented biomolecules in the extracts have demonstrated in vitro antioxidant activity, they did not show a significant effect on PC3 cells. However, this study opens up broad perspective for the further comprehensive investigation of these, commercial, seaweed's biopotential.

Bioactive Compounds of Seaweeds and Their Effects on Certain Types of Cancer

Cancer is considered as one of the major health problems worldwide. So far, no completely effective method has been found for cancer treatment. Therefore, the rise of using natural products has been proposed as an alternative therapy in this regard. For many years, the seaweed has been a source of many functional bioactive compounds including polysaccharides, polyphenols, pigments, terpenes, and many others. These compounds have shown many bioactivities including anticancer activity against different kinds of cancer. Bioactive compounds obtained from the seaweed have been demonstrated to cause apoptosis in cancer cells and trigger cell cycle arrest with low cytotoxicity against normal cells. In this review, it was attempted to shed light on the anticancer activity of some seaweed-derived bioactive compounds.

The Potential Role of Nutraceuticals as an Adjuvant in Breast Cancer Patients to Prevent Hair Loss Induced by Endocrine Therapy

Nutraceuticals, natural dietary and botanical supplements offering health benefits, provide a basis for complementary and alternative medicine (CAM). Use of CAM by healthy individuals and patients with medical conditions is rapidly increasing. For the majority of breast cancer patients, treatment plans involve 5–10 yrs of endocrine therapy, but hair loss/thinning is a common side effect. Many women consider this significant, severely impacting on quality of life, even leading to non-compliance of therapy. Therefore, nutraceuticals that stimulate/maintain hair growth can be proposed. Although nutraceuticals are often available without prescription and taken at the discretion of patients, physicians can be reluctant to recommend them, even as adjuvants, since potential interactions with endocrine therapy have not been fully elucidated. It is, therefore, important to understand the modus operandi of ingredients to be confident that their use will not interfere/interact with therapy. The aim is to improve clinical/healthcare outcomes by combining specific nutraceuticals with conventional care whilst avoiding detrimental interactions. This review presents the current understanding of nutraceuticals beneficial to hair wellness and outcomes concerning efficacy/safety in breast cancer patients. We will focus on describing endocrine therapy and the role of estrogens in cancer and hair growth before evaluating the effects of natural ingredients on breast cancer and hair growth.

Interactions of fibroblast growth factors with sulfated galactofucan from Saccharina japonica

A total 68 types of marine algae oligosaccharides and polysaccharides were prepared and used to study the structure-activity relationship of oligosaccharides and polysaccharides in their interactions with fibroblast growth factors (FGF) 1 and 2. Factors considered include different types of algae, extraction methods, molecular weight, sulfate content and fractions. In the case of low molecular weight polysaccharide (SJ-D) from Saccharina japonica and its fractions eluting from anion exchange column, both 1.0 M NaCl fraction (SJ-D-I) and 2.0 M NaCl fraction (SJ-D-S) had stronger binding affinity than the parent SJ-D, suggesting that sulfated galactofucans represented the major tight binding component. Nuclear magnetic resonance showed that SJ-D-I was a typical sulfated galactofucan, composed of four units: 1, 3-linked 4-sulfated α-L-fucose (Fuc); 1, 3-linked 2, 4-disulfated α-L-Fuc; 1, 6-linked 4-sulfated β-D-Gal and/or 1, 6-linked 3, 4-sulfated β-D-Gal. Modification by autohydrolysis to oligosaccharides and desulfation decreased the FGF binding affinity while oversulfation increased the affinity. The solution-based affinities of SJ-D-I to FGF1 and FGF2 were 69 nM and 3.9 nM, suggesting that SJ-D-I showed better preferentially binding to FGF1 than a natural ligand, heparin, suggesting that sulfated galactofucan might represent a good regulator of FGF1.

Associations of Japanese food intake with survival of stomach and colorectal cancer: A prospective patient cohort study

Dietary factors may affect the prognosis of digestive tract cancer, but evidence has been sparse. We investigated the association between pretreatment intake of 6 Japanese foods (including soy food, miso [soybean paste] soup and seaweed) and the risk of death among patients with histologically confirmed major digestive tract cancers (stomach, 1931; colon, 793; rectum, 510) diagnosed during 1997‐2013 at a single institution in Japan. Pretreatment dietary intake was assessed using a food frequency questionnaire, and the patients were followed until December 2016. The Cox proportional hazards model was used to estimate hazard ratios (HR) and 95% confidence intervals (CI). Among the patients with stomach cancer, frequent intake of soy food was inversely associated with the risk of all‐cause (P_trend for four frequency groups = 0.01; HR = 0.72, 95% CI: 0.50‐1.04 for highest vs lowest group) and stomach cancer (P_trend = 0.03; HR = 0.63, 95% CI: 0.40‐0.99) death. A similar inverse association was also found for intake of miso soup. In contrast, frequent seaweed intake was inversely associated with the risk of all‐cause death among the patients with colon cancer (P_trend = 0.03). Rectal cancer patients who had frequently consumed seaweed tended to have a lower risk of rectal cancer death (P_trend = 0.02). These findings indicate that pretreatment intake of Japanese foods such as soybean products and seaweed may have favorable effects on patient survival of stomach and colorectal cancer, although this needs to be confirmed by further research.

Reflexin A, a new indole alkaloid from Rauvolfia reflexa induces apoptosis against colon cancer cells

One new indole alkaloid, reflexin A (1), and two known indoles, macusine B (2) and vinorine (3), were isolated from the bark of Rauvolfia reflexa. Their structures were elucidated by 1D and 2D NMR, UV, IR, and MS spectroscopic analyses. Compound 1 displayed anticancer activity against HCT-116 colon cancer cells with an IC₅₀ value of 30.24 ± 0.75 µM. The results implied that the newly isolated 1 induced apoptosis in HCT-116 cells, suggesting its possible role as an anticancer agent. In vivo acute toxicity study was performed on compound 1 to evaluate its safety profile.

Antioxidant, Anticancer Activity and Phytochemical Analysis of Green Algae, Chaetomorpha Collected from the Arabian Gulf

Seaweeds are a group of marine multicellular algae; the presence of antioxidant phytochemical constituents in Seaweed Chaetomorpha sp. extracts has received attention for their role in the prevention of human diseases. This study explores the phytochemical constituents, antioxidant, and anticancer properties of the Cladophoraceae, Chaetomorpha sp. Energy dispersive x-ray spectroscopy (EDX), and Gas chromatography-mass spectrometry (GC/MS) were performed to study the chemical structure and chemical formula. Different concentrations of ethanol and aqueous extracts of Chaetomorpha were used to estimate antioxidant activity by 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity and total flavonoid, phenolic, and tannins content assays. Anti-tumor activity against breast cancer cell lines (MCF-7 and MDA-MB-231) was assessed by 3-(4,5-Dimethylthiazol-2-cyl)-2,5-Diphenyltetrazolium Bromide (MTT) assay. The EDX analysis indicated the presence of oxygen, silicon, and calcium as dominant elements. Antioxidant assays indicated that the ethanol extracts of Chaetomorpha consisted of a total of 189.14 ± 0.99 mg QE/g flavonoid content, 21.92 ± 0.43 mg GAE/g phenolic content and 21.81 ± 0.04 mg GAE/g tannins content. The DPPH radical scavenging assay exhibited higher antioxidant activity IC₅₀ (9.41 ± 0.54 mg/mL) in the ethanol extract. Moreover, it showed high anticancer activity by growth inhibition in the MDA-MB-231 breast cancer cell line and low IC₅₀ (225.18 ± 0.61 µg/mL). GC/MS analysis revealed the presence of Dichloracetic acid (DCA) as the active antitumor constituent of Chaetomorpha sp.; other anticancer compounds identified were Oximes and L-α-Terpinol. The results revealed that the type of Chaetomorpha sp. studied here possesses very unique and novel constituents and active potent antitumor chemical constituents and it can act as a promising antioxidant and anticancer agent for future applications in pharmaceutical industries.

Seaweed and seaweed-derived metabolites as prebiotics

Seaweeds and their bioactive compounds, particularly polysaccharides and phenolics can be regarded as great dietary supplements with gut health benefits and prebiotics. These components are resistant to digestion by enzymes present in the human gastrointestinal tract, also selectively stimulate the growth of beneficial gut bacteria and the production of fermentation products such as short chain fatty acids. Commonly, the health benefits of seaweed components are assessed by including them in an in vitro anaerobic fermentation system containing human fecal inocula that mimics the environment of the human large bowel. Regarding to the complex interactions between dietary components, gastrointestinal physiological processes, and gut microbiota are difficult to model in vitro. Consequently it is important to follow up the promising in vitro results with in vivo animal or human testing. The aim of this chapter is to have a comprehensive review on the application of seaweeds and seaweed-derived metabolites as prebiotics, and understand the trends, gaps and future directions of both scientific and industrial developments. This work contributes to develop and expand new platform of seaweed utilization for higher-value products, particularly to functional food and nutraceutical industries in order to serve the social demand for health awareness and support economic development.

Variation in Lipid Components from 15 Species of Tropical and Temperate Seaweeds

The present study describes the variation in lipid components from 15 species of seaweeds belonging to the Chlorophyta, Ochrophyta, and Rhodophyta phyla collected in tropical (Indonesia) and temperate (Japan) areas. Analyses were performed of multiple components, including chlorophylls, carotenoids, n-3 and n-6 polyunsaturated fatty acids (PUFAs), and alpha tocopherol (α-Toc). Chlorophyll (Chl) and carotenoid contents varied among phyla, but not with the sampling location. Chl a and b were the major chlorophylls in Chlorophyta. Chl a and Chl c were the main chlorophylls in Ochrophyta, while Chl a was the dominant chlorophylls in Rhodophyta. β-Carotene and fucoxanthin were detected as major seaweed carotenoids. The former was present in all species in a variety of ranges, while the latter was mainly found in Ochrophyta and in small quantities in Rhodophyta, but not in Chlorophyta. The total lipids (TL) content and fatty acids composition were strongly affected by sampling location. The TL and n-3 PUFAs levels tended to be higher in temperate seaweeds compared with those in tropical seaweeds. The major n-3 PUFAs in different phyla, namely, eicosapentaenoic acid (EPA) and stearidonic acid (SDA) in Ochrophyta, α-linolenic acid (ALA) and SDA in Chlorophyta, and EPA in Rhodophyta, accumulated in temperate seaweeds. Chlorophylls, their derivatives, and carotenoids are known to have health benefits, such as antioxidant activities, while n-3 PUFAs are known to be essential nutrients that positively influence human nutrition and health. Therefore, seaweed lipids could be used as a source of ingredients with health benefits for functional foods and nutraceuticals.

Macroalgae as a Valuable Source of Naturally Occurring Bioactive Compounds for the Treatment of Alzheimer's Disease

Alzheimer's disease (AD) is a neurological condition that affects mostly aged individuals. Evidence suggests that pathological mechanisms involved in the development of AD are associated with cholinergic deficit, glutamate excitotoxicity, beta-amyloid aggregation, tau phosphorylation, neuro-inflammation, and oxidative damage to neurons. Currently there is no cure for AD; however, synthetic therapies have been developed to effectively manage some of the symptoms at the early stage of the disease. Natural products from plants and marine organisms have been identified as important sources of bioactive compounds with neuroprotective potentials and less adverse effects compared to synthetic agents. Seaweeds contain several kinds of secondary metabolites such as phlorotannins, carotenoids, sterols, fucoidans, and poly unsaturated fatty acids. However, their neuroprotective effects and mechanisms of action have not been fully explored. This review discusses recent investigations and/or updates on interactions of bioactive compounds from seaweeds with biomarkers involved in the pathogenesis of AD using reports in electronic databases such as Web of science, Scopus, PubMed, Science direct, Scifinder, Taylor and Francis, Wiley, Springer, and Google scholar between 2015 and 2019. Phlorotannins, fucoidans, sterols, and carotenoids showed strong neuroprotective potentials in different experimental models. However, there are no data from human studies and/or clinical trials.

Associations among dietary seaweed intake, c-MYC rs6983267 polymorphism, and risk of colorectal cancer in a Korean population: a case-control study

PURPOSE

The effects of seaweed compounds have been studied in relation to colorectal cancer (CRC) based on their ability to modulate carcinogen metabolism in vivo and in vitro. However, no epidemiological studies on the interaction between edible seaweed and genetic variants relevant to CRC have been reported. This study examined the associations among dietary seaweed intake (gim, miyeok, and dashima), single-nucleotide polymorphisms (SNPs; rs6983267, rs7014346, and rs719725), and CRC risk in a Korean population.

METHODS

The participants comprised 923 CRC patients and 1846 controls who visited the National Cancer Center Korea. We used a Semiquantitative Food Frequency Questionnaire and genotyped SNPs using genomic DNA samples.

RESULTS

The intake of total seaweed, miyeok, and dashima showed a significant inverse association with CRC risk after adjusting for potential confounding factors (total seaweed odds ratio (OR) [95% CI] = 0.65 [0.50-0.85], P for trend < 0.001; miyeok = 0.82 [0.62-1.09], P for trend < 0.05; dashima = 0.58 [0.44-0.76], P for trend < 0.001, highest vs. lowest tertile). We confirmed that the homozygous T/T allele of rs6983267 c-MYC indicated an interaction between dietary seaweed intake and both overall CRC and rectal cancer (CRC OR [95% CI] = 0.52 [0.34-0.81], P for interaction = 0.015; rectal cancer = 0.45 [0.25-0.79], P for interaction = 0.007, T/T carriers with high total seaweed intake vs. T/T carriers with low total seaweed intake).

CONCLUSIONS

This study provides evidence of the effect of dietary seaweed intake on CRC risk with respect to c-MYC gene variants.

Aqueous-ethanol extracts of some South African seaweeds inhibit beta-amyloid aggregation, cholinesterases, and beta-secretase activities in vitro

In this study, we evaluated the anti-amyloidogenic, anticholinesterase, and antioxidant potentials of hydroethanolic extracts of Ecklonia maxima (ECK), Gelidium pristoides (GLD), Gracilaria gracilis (GCL), and Ulva lactuca (ULT). The effect of the extracts on β-amyloid (Aβ1-42 ) peptide were determined using electron microscope. The effects of the extracts on β-secretase and cholinesterase activities, as well as their radical scavenging and metal chelating activities were also assessed. Electron micrographs revealed that ECK, GLD, GCL, and ULT incubated with Aβ1-42 at different intervals (0-96 hr) showed very low levels of fibrils compared to the control. The extracts also inhibited β-secretase, acetylcholinesterase, and butyrylcholinesterase activities in a dose-dependent manner. Furthermore, the extracts scavenged hydroxyl radicals and were able to chelate Fe2+ in a dose-dependent manner. Our findings suggest that the seaweed extracts are potential sources of lead compounds and novel inhibitors of β-amyloid aggregation, β-secretase, and cholinesterases for the management of Alzheimer's diseases. PRACTICAL APPLICATIONS: Seaweeds have been identified as good sources of naturally occurring bioactive compounds with several medicinal properties. They are commonly used as functional foods and development of nutraceuticals, dietary supplements, and cosmeceuticals. However, the neuroprotective effects of many species of seaweeds have not been fully explored. The findings of this study suggests that Gracilaria gracilis, Ulva lactuca, Ecklonia maxima, and Gelidium pristoides are potential sources of cholinesterase, beta-secretase, and amyloid protein aggregation inhibitors. Hence, this support the use of these seaweeds as alternative sources of antioxidants and natural compounds with neuroprotective potentials for the management of Alzheimer's disease.

Cytotoxic activity of the seaweed compound fucosterol, alone and in combination with 5-fluorouracil, in colon cells using 2D and 3D culturing

Colorectal cancer (CRC) is one of the most frequently occurring carcinomas which require effective therapies. Fucosterol is a sterol present in marine brown seaweeds with several biological activities. However, the influence of fucosterol in CRC remains to be determined. Thus, the aim of this study was to examine the anticancer activity of fucosterol alone and in combination with 5-fluorouracil (5-Fu) on two human CRC cell lines (HCT116 and HT29) and compared with cytotoxicity in one normal colon fibroblast cell line (CCD-18co) in monolayer (2D). The effect of fucosterol alone or in combination with 5-Fu was further assessed using HT29 multicellular spheroids (3D). Data demonstrated that fucosterol alone or combined with 5-Fu decreased cell viability in HT29 cells in 2D cultures without inducing cytotoxic in normal colon cells. The combination, fucosterol, and 5-Fu, also inhibited cell proliferation, clonogenic potential and cell migration without producing cell death in 2D. In multicellular spheroids, the combination fucosterol plus 5-Fu at the same concentrations used in 2D was not effective demonstrating that under the tested conditions the 3D model was more resistant than the 2D model. Taken together, these findings suggest that fucosterol might be a promising alternative to enhance the cytotoxic and anti-invasive actions of 5-Fu in colon cancer cells without consequent major adverse effects in normal cells. Our results also reinforce the need to include more complex 3D culture models in the initial stages of drug screening.

Brown and Red Seaweeds Serve as Potential Efflux Pump Inhibitors for Drug-Resistant Escherichia coli

Multidrug-resistant pathogens are a significant clinical problem. Efflux pump inhibitors (EPIs) can restore the activities of existing antibiotics by interfering with drug efflux pumps located in bacterial cell membranes. Seaweeds are important sources of biologically active metabolites of natural origin; however, their potential as EPIs remains uninvestigated. Here, functional extracts from the brown seaweeds Laminaria japonica and Sargassum horneri and the red seaweeds Gracilaria sp. and Porphyra dentata were evaluated as potential EPIs against drug-resistant Escherichia coli. All these extracts were found to potentiate the activities of drugs in modulation tests, although not to the same extent. Synergistic effects of the extracts and the drug clarithromycin were observed from the onset of Time-kill assays, with no evidence of bacterial regrowth. Ethidium bromide accumulation studies revealed that the efflux decreased in the presence of each extract, as indicated by the presence of EPIs. Most identified EPIs that have been discovered to date have aromatic structures, and the seaweed extracts were found to contain various terpenes, terpenoids, phenolic compounds, indoles, pyrrole derivatives, alkaloids, and halogenated aromatic compounds. Our study highlights the potential of these compounds of the seaweeds as drug EPIs.

Role of Green Macroalgae Enteromorpha Prolifera Polyphenols in the Modulation of Gene Expression and Intestinal Microflora Profiles in Type 2 Diabetic Mice

Effects of green macroalgae 55% ethanolic extract Enteromorpha prolifera through an ultrafiltration membrane of 3 kDa (EPE3k) on antidiabetic activity, gut microbiota, and regulation mechanism were investigated in high-fat/high-sucrose diet and streptozocin-induced diabetic mice. The structural characterizations of its major compounds in EPE3k were determined by ultra-performance liquid chromatography-quadrupole/time of flight mass spectrometry. Furthermore, the intestinal microflora modulation in diabetic mice was also investigated with high-throughput 16S rRNA gene sequencing. The proposed presence of polyphenols in EPE3k was confirmed. EPE3k could significantly decrease the fasting blood glucose and improve fasting glucose tolerance. The hypoglycemic effect of EPE3k was via activation of phosphatidylinositol 3-kinase and suppression of c-Jun N-terminal kinase in liver. EPE3k treatment significantly increased the relative abundance of Akkermansia and decreased the proportion of Alistipes and Turicibacter. The above results indicated that EPE3k could be provided as a new potential therapy for the treatment of type 2 diabetic mellitus.

Antidiarrheal activity of a novel sulfated polysaccharide from the red seaweed Gracilaria cervicornis

ETHNOPHARMACOLOGICAL RELEVANCE

The use of marine seaweeds as a source of natural compounds with medicinal purposes is increasing in Western countries in the last decades, becoming an important alternative in the traditional medicine of many developing countries, where diarrhea still remains a severe public health problem, with high rates of mortality and morbidity. Sulfated polysaccharides (PLS) extracted from red seaweeds can exhibit therapeutic effects for the treatment of gastrointestinal disorders. Thus, the pharmacological properties of the PLS from Gracilaria cervicornis, an endemic seaweed found in the Brazilian northeast coast, was evaluated as an alternative natural medication for diarrhea.

AIM OF THE STUDY

This study aimed to evaluate the antidiarrheal activity of sulfated polysaccharides (PLS) extracted from the red seaweed G. cervicornis in Swiss mice pre-treated with castor oil or cholera toxin.

MATERIALS AND METHODS

The seaweed Gracilaria cervicornis was collected at Flecheiras beach (city of Trairí, State of Ceará, Brazil) and the PLS was obtained through enzymatic extraction and administered in mice (25-30 g) before diarrhea induction with castor oil or cholera toxin. For the evaluation of the total number of fecal output and diarrheal feces, the animals were placed in cages lined with adsorbent material. The evaluation of intestinal fluid accumulation (enteropooling) on castor oil-induced diarrhea in mice occurred by dissecting the small intestine and measuring its volume. The determination of Na⁺/K⁺-ATPase activity was measured in the small intestine supernatants by colorimetry, using commercial biochemistry kits. The gastrointestinal motility was evaluated utilizing an activated charcoal as a food tracer. The intestinal fluid secretion and chloride ion concentration were evaluated in intestinal closed loops in mice with cholera toxin-induced secretory diarrhea. The binding ability of PLS with GM1 and/or cholera toxin was evaluated by an Enzyme-Linked Immunosorbent Assay (ELISA).

RESULTS

The G. cervicornis PLS showed antidiarrheal effects in both acute and secretory diarrhea, reducing the total number of fecal output, diarrheic stools, intestinal fluid accumulation, and increasing small intestine Na⁺/K⁺-ATPase activity on castor oil-induced diarrhea. However, the PLS did not affect gastrointestinal motility, indicating that this compound has a different action mechanism than loperamide. In secretory diarrhea, the PLS decreased intestinal fluid secretion and small intestine chloride excretion, binding with GM1 and/or cholera toxin and blocking their attachment to the enterocyte cell surface.

CONCLUSIONS

In conclusion, PLS has a significant antidiarrheal effect in acute and secretory diarrhea. Further investigation is needed towards its use as a natural medicine to treat diarrhea.

Drug resistance in glioblastoma and cytotoxicity of seaweed compounds, alone and in combination with anticancer drugs: A mini review

BACKGROUND

Glioblastomas (GBM) are one of the most aggressive tumor of the central nervous system with an average life expectancy of only 1-2 years after diagnosis, even with the use of advanced treatments with surgery, radiation, and chemotherapy. There are several anticancer drugs with alkylating properties that have been used in the therapy of malignant gliomas. Temozolomide (TMZ) is one of them, widely used even in combination with ionizing radiation. However, the main disadvantage of using these types of drugs in the treatment of GBM is the development of cancer drug resistance. Research of bioactive compounds with anticancer activity has been heavily explored.

PURPOSE

This review focuses on a carotenoid and a phlorotannin present in seaweed, namely fucoxanthin and phloroglucinol, and their anticancer activity against glioblastoma. The combination of natural compounds with conventional drugs is also discussed.

CONCLUSION

Several natural compounds existing in seaweeds, such as fucoxanthin and phoroglucinol, have shown cytotoxic activity in models in vitro and in vivo, acting through different molecular mechanisms, such as antioxidant, antiproliferative, DNA damage/DNA repair, proapoptotic, antiangiogenic and antimetastic. Within the scope of interactions with conventional drugs, there are evidences that some seaweed compounds could be used to potentiate the action of anticancer drugs. However, their effects and mechanisms of action, alone or in combination with anticancer drugs, namely TMZ, in glioblastoma cell, still few explored and require more attention due to the unquestionable high potential of these marine compounds.

Investigation of antioxidant and anticancer potential of fucoidan from Sargassum polycystum

The present study was aimed to evaluate the antioxidant and anticancer potential of fucoidan isolated from Sargassum polycystum. The isolated fucoidan was successfully purified by DEAE cellulose-ion exchange chromatography and dialysis. Totally four active fractions (F1-F4) were collected and explored its chemical constitution by calorimetric assays. Among them, fraction 2 (F2) showed the higher yield percentage, fucose and sulphate content. Further, monosaccharide composition, structural and functional properties of the F2 was analyzed by HPLC, FTIR and NMR. F2 shows highest DPPH radical scavenging activity (55.94 ± 0.69%), reducing power (0.33 absorbance rate), hydrogen peroxide scavenging activity (71.76 ± 2.14%) and nitric oxide radical scavenging activity (51.81 ± 1.04%) at 1000 μg/ml. The cell viability of MCF-7 and HCT-15 cell lines was proportionate to the concentration of F2 with an estimated IC50 was 20 and 50 μg/ml respectively. The fluorescence and confocal laser scanning microscopic analysis demonstrated the apoptotic morphological changes and cell mediated death in F2 treated cancer cells. Higher amount of LDH release was found in the F2 treated cancer cells than the control group. Thus, the present finding proved that the isolated F2 encompasses significant antioxidant and anticancer property.

From Marine Origin to Therapeutics: The Antitumor Potential of Marine Algae-Derived Compounds

Marine environment has demonstrated to be an interesting source of compounds with uncommon and unique chemical features on which the molecular modeling and chemical synthesis of new drugs can be based with greater efficacy and specificity for the therapeutics. Cancer is a growing public health threat, and despite the advances in biomedical research and technology, there is an urgent need for the development of new anticancer drugs. In this field, it is estimated that more than 60% of commercially available anticancer drugs are natural biomimetic inspired. Among the marine organisms, algae have revealed to be one of the major sources of new compounds of marine origin, including those exhibiting antitumor and cytotoxic potential. These compounds demonstrated ability to mediate specific inhibitory activities on a number of key cellular processes, including apoptosis pathways, angiogenesis, migration and invasion, in both in vitro and in vivo models, revealing their potential to be used as anticancer drugs. This review will focus on the bioactive molecules from algae with antitumor potential, from their origin to their potential uses, with special emphasis to the alga Sphaerococcus coronopifolius as a producer of cytotoxic compounds.

Seaweed Extract (Stella Maris®) Activates Innate Immune Responses in Arabidopsis thaliana and Protects Host against Bacterial Pathogens

Insects and pathogenic infections (bacteria, viruses and fungi) cause huge losses in agriculturally important crops yearly. Due to the rise in pesticide and antibiotic resistance, our crops and livestock are increasingly at risk. There is a rising demand for environmentally friendly solutions to prevent crop decreases. Components of Ascophyllum nodosum seaweed extracts were recently found to boost plant immunity. The stimulatory activities of the A.nodosum marine alga-derived extract (Stella Maris®) were investigated in a broad range of immune assays. Elevated hydrogen peroxide production measured in a chemiluminescence assay suggested that the extract elicited a strong burst of reactive oxygen species. Arabidopsis seedlings treated with Stella Maris® activated the expression of WRKY30, CYP71A12 and PR-1 genes, the induction of which represent early, mid and late plant immune response, respectively. Finally, this study found that Stella Maris® inhibited the growth of multiple bacterial pathogens, including an opportunistic human pathogen that has demonstrated pathogenicity in plants. In summary, the pre-treatment with the seaweed extract protected Arabidopsis against subsequent infection by these pathogens.

Polysaccharides from Sargassum thunbergii: Monthly variations and anti-complement and anti-tumour activities

Monthly variations of polysaccharides from Sargassum thunbergii and their anti-complement and anti-tumour activities were investigated. It was observed that an increase in fucose and total sugar contents occurred during the growth period (from early April to mid-June), accompanied by a decrease in molar ratios of other monosaccharides to fucose. The highest yields were obtained from early July to early September, which was in accordance with the significant increase in molar ratio of glucose to fucose and decrease in molar ratio of other monosaccharides to fucose. And the above results suggested that S. Thunbergii synthesized large amount of laminaran, the storage substance of brown algae, during the senescence period. However, sulfate contents were relatively stable in the life cycle of S. thunbergii. These results suggested that S. thunbergii synthesized complex sulfated heteropolysacchairdes during inactive period, while during other periods, it synthesized more sulfated galactofucan. All polysaccharides showed anti-complement activity, suggesting that the harvesting time did not influence the anti-complement activities. In the anti-tumour assay in vitro, the polysaccharides taken during the senescence period had much lower anti-tumour activity, suggesting that fucoidan, but not laminaran, determined the anti-tumour activities. Therefore, polysaccharides from S. thunbergii might have great potential in anti-complement and anti-tumour application.