Fucoidan derived from Undaria pinnatifida induces apoptosis in human hepatocellular carcinoma SMMC-7721 cells via the ROS-mediated mitochondrial pathway

Clinical applications of fucoidan in translational medicine for adjuvant cancer therapy

The chemical composition of fucoidan, a kind of sulfated polysaccharide mainly derived from brown seaweed, includes a substantial percentage of l-fucose. Fucoidan has various biological and pharmacological activities, such as anti-cancer/anti-tumor, anti-proliferation, anti-inflammatory and immune-modulatory functions, and fucoidan-related dietary supplements and nutraceuticals have recently drawn considerable attention. In this review, we aim to provide a current view of different aspects of fucoidan biological activity, with a focus on the anti-cancer regulatory effects of fucoidan on growth signaling mechanisms. First, we discuss historical aspects of fucoidan and fucoidan products, as well as the anti-cancer effects of fucoidan on various cancer cells. Second, we discuss fucoidan’s biological activities and induction of cell death in cancer cells, including multiple mechanisms and signal transduction pathways related to its anti-cancer effects. Next, we focus on fucoidan and fucoidan-derived products that have been marketed as dietary supplements or nutraceuticals for cancer, including anti-cancer effects of fucoidan when combined as an adjuvant with clinical drugs. Finally, case studies of fucoidan in complementary therapy and as an alternative medicine in animal and mouse models and human clinical trials to alleviate side effects of anti-cancer chemotherapy are discussed. Combining fucoidan with clinical therapeutic agents in the treatment of cancer patients, dissecting the related signal transduction pathways and investigating their dynamic interactions may reveal potential molecular targets in cancer prevention, therapies and key obstacles in the current development of anti-cancer strategies.

The Effect of Fucoidan, a Potential New, Natural, Anti-Neoplastic Agent on Uterine Sarcomas and Carcinosarcoma Cell Lines: ENITEC Collaborative Study

The aim of the study was to assess the activity of fucoidan on the uterine sarcomas (MES-SA and ESS-1) and carcinosarcoma cell lines (SK-UT-1 and SK-UT-1B) and its toxicity on the human skin fibroblasts (HSF). Two uterine sarcomas and two carcinosarcoma cell lines were examined, as a control HSF were used. Cell viability was assessed with MTT test, apoptosis with caspase-3 activity and cell cycle by assessment of DNA synthesis. Fucoidan significantly decreases cell viability in SK-UT-1, SK-UT-1B, and ESS-1 cell lines, such effect was not observed in MES-SA. Fucoidan was not substantially affecting proliferation among normal cells. The tested agent induced apoptosis in all cell cultures used in the experiment. Fucoidan affects cell cycle of all tested cell lines except MES-SA by increasing percentage of cells in G0/sub-G1/G1 phase. Fucoidan do not only affect proliferation but induces apoptosis in selected uterine sarcoma and carcinosarcoma cell lines, so it has potential to be used as cytotoxic agent. Fucoidan seems to be promising anti-cancer agent for endometrial stromal sarcoma and carcinosarcoma.

Comparison of structure and in vitro anticancer activity of native and modified fucoidans from Sargassum feldmannii and S. duplicatum

Fucoidans are valuable biologically active polysaccharides of brown algae. The aim of this study was to investigate the structure of fucoidan from Sargassum feldmannii and the anticancer effects of native and modified polysaccharides from S. feldmannii and S. duplicatum. The structure of sulfated (25.3%) galactofucan SfF2 (Fuc/Gal = 72/28 mol%) from S. feldmannii was investigated by NMR spectroscopy of desulfated derivative and mass spectrometry of fucoidan fragments labelled with 18O. SfF2 was shown to contain the main chain from 1,3-linked α-l-fucopyranose and β-d-galactopyranose residues with fucose branches at C4 and C6 of galactose residues and C2 of fucose residues. The following fragments were also identified in SfF2: Fuc-(1,4)-Fuc, Gal-(1,3)-Gal, and Gal-(1,4)-Gal. The sulfate groups occupied positions C2, C3, and C4 of fucose residues and C2, C3, C4, and C6 of galactose residues. The galactofucans from S. feldmannii, S. duplicatum, and their derivatives exhibited no cytotoxicity in vitro. The native and deacetylated fucoidans (200 μg/mL) inhibited colony formation of human colon cancer cells (DLD-1, HT-29, and HCT-116). Both desulfated fucoidans possessed weak anticancer activity.

Pathway Analysis of Fucoidan Activity Using a Yeast Gene Deletion Library Screen

Fucoidan, the sulfated fucose-rich polysaccharide derived from brown macroalgae, was reported to display some anti-cancer effects in in vitro and in vivo models that included apoptosis and cell cycle arrest. The proposed mechanisms of action involve enhanced immune surveillance and direct pro-apoptotic effects via the activation of cell signaling pathways that remain largely uncharacterized. This study aimed to identify cellular pathways influenced by fucoidan using an unbiased genetic approach to generate additional insights into the anti-cancer effects of fucoidan. Drug⁻gene interactions of Undaria pinnatifida fucoidan were assessed by a systematic screen of the entire set of 4,733 halpoid Saccharomyces cerevsiae gene deletion strains. Some of the findings were confirmed using cell cycle analysis and DNA damage detection in non-immortalized human dermal fibroblasts and colon cancer cells. The yeast deletion library screen and subsequent pathway and interactome analysis identified global effects of fucoidan on a wide range of eukaryotic cellular processes, including RNA metabolism, protein synthesis, sorting, targeting and transport, carbohydrate metabolism, mitochondrial maintenance, cell cycle regulation, and DNA damage repair-related pathways. Fucoidan also reduced clonogenic survival, induced DNA damage and G1-arrest in colon cancer cells, while these effects were not observed in non-immortalized human fibroblasts. Our results demonstrate global effects of fucoidan in diverse cellular processes in eukaryotic cells and further our understanding about the inhibitory effect of Undaria pinnatifida fucoidan on the growth of human cancer cells.

The anti-tumor activity of brown seaweed oligo-fucoidan via lncRNA expression modulation in HepG2 cells

Hepatocellular carcinoma (HCC) is the third most common cause of cancer-related death in Asia. HCC is less sensitive to chemotherapy and is known to express multidrug resistant genes to acquire resistance to chemotherapeutic agents, therefore the development of a potent HCC suppressor is essential in treating HCC. Our previous reports demonstrated that oligo-fucoidan from the brown seaweed Sargassum hemiphyllum elevates microRNA-29b to inhibit epithelial-mesenchymal transition in hepatoma cells. In this study, we aimed to examine in vitro effect of oligo-fucoidan in hepatocellular carcinoma through apoptosis and long noncoding RNA (lncRNA) pathway. Oligo-fucoidan was studied for its anti-hepatoma cells by MTT and DNA ladder analysis. And the mechanism was studied by flow cytometry, qPCR and western blot analysis. In this study, oligo-fucoidan induced sub-G1 phase cell cycle arrest and activation of caspases, indicating that the intrinsic and extrinsic apoptotic pathways were involved in the mechanism of oligo-fucoidan-induced cell death. Moreover, oligo-fucoidan significantly increased the expression of p53, p21, and p27, while cyclin-B1 and -D1 were decreased at the mRNA and protein levels. Finally, we showed that targeting apoptosis and cell cycle pathways could also contribute to the induction of the lncRNA-Saf and lncRNA-p21. Through human lncRNA profiler array analysis, the differential expression of lncRNAs in HCC cells following oligo-fucoidan exposure was further examined. These findings indicated that lncRNAs switched oligo-fucoidan-induced apoptosis, which might be potentially valuable in HCC adjuvant therapy.

New Drugs from the Sea: Pro-Apoptotic Activity of Sponges and Algae Derived Compounds

Natural compounds derived from marine organisms exhibit a wide variety of biological activities. Over the last decades, a great interest has been focused on the anti-tumour role of sponges and algae that constitute the major source of these bioactive metabolites. A substantial number of chemically different structures from different species have demonstrated inhibition of tumour growth and progression by inducing apoptosis in several types of human cancer. The molecular mechanisms by which marine natural products activate apoptosis mainly include (1) a dysregulation of the mitochondrial pathway; (2) the activation of caspases; and/or (3) increase of death signals through transmembrane death receptors. This great variety of mechanisms of action may help to overcome the multitude of resistances exhibited by different tumour specimens. Therefore, products from marine organisms and their synthetic derivates might represent promising sources for new anticancer drugs, both as single agents or as co-adjuvants with other chemotherapeutics. This review will focus on some selected bioactive molecules from sponges and algae with pro-apoptotic potential in tumour cells.

Dendrobium candidum extract inhibits proliferation and induces apoptosis of liver cancer cells by inactivating Wnt/β-catenin signaling pathway

BACKGROUND

Dendrobium candidum extract (DCE) has been reported to have anti-tumor property. However, the effect of DCE on liver cancer has not been well explored. This study was aimed to evaluate the inhibitory effect of DCE on liver cancer cells.

METHODS

The effect of DCE on liver cancer cells was analyzed by detecting cell viability by MTT assay, detecting colony formation ability by colony formation assay, determining apoptotic cell rate, cell cycle distribution, active caspase-3 positive cells, Ki-67 positive cells, reactive oxygen species (ROS) level, and mitochondrial transmembrane potential (MMP) by flow cytometry analysis, and analyzing changes of expressions of cell cycle-, apoptosis-, and Wnt/β-catenin pathway-related proteins by Western blot.

RESULTS

DCE inhibited viability and promoted apoptosis of liver cancer cell lines SMMC-7721 and BEL-7404. DCE decreased colony formation, induced cell cycle arrest, and led to cell cycle-associated proteins' abnormal expressions in SMMC-7721 and BEL-7404 cells. DCE effectively suppressed viability and proliferation of primary liver cancer cells and also induced aberrant expressions of cell cycle- and apoptosis-related proteins. After DCE treatment, ROS level was increased and MMP level was decreased. DCE inhibited β-catenin level in the nucleus and regulated downstream genes of β-catenin and further blocked Wnt/β-catenin pathway in SMMC-7721 and BEL-7404 cells as well as primary liver cancer cells.

CONCLUSION

DCE suppressed liver cancer SMMC-7721 and BEL-7404 cells as well as primary liver cancer cells likely though activating mitochondria apoptosis pathway and inducing inhibition of Wnt/β-catenin pathway.

Structural characterization and antitumor effects of fucoidans from brown algae Kjellmaniella crassifolia farmed in northern China

Brown alga-derived fucoidan has been proven to have a variety of bioactivities. To explore the antitumor effect of fucoidan, Kjellmaniella crassifolia (farmed in Dalian, China)was enzymatically digested to obtain the crude extract (F), which was further separated into three fractions (F1, F2 and F3). The monosaccharide composition and structural characteristics of the isolated fractions were determined using high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR) and 1D and 2D nuclear magnetic resonance (NMR) spectroscopy. F1 is an acetylated galactofucan, and F2 consists of fucose, galactose, mannose and glucuronic acid. F3 has two components, an acetylated galactofucan and a pure sulfated fucan. F, F1 and F2 showed limited cytotoxicity against murine hepatocarcinoma Hca-F cells in vitro. Oral administration of F at a dose of 450 mg/kg d significantly inhibited lump growth in Hca-F-inoculated mice and led to upregulated FAS expression in tumor tissues compared to that of the control. F1 and F2 did not show competitive antineoplastic efficacy, as did the crude extract. Crude fucoidan could be a promising antitumor adjuvant. The origin of its efficacy may be the small molecules, such as phenols that attached to native fucoidan. This theory needs to be further confirmed.

Anti-inflammatory effect of low molecular weight fucoidan from Saccharina japonica on atherosclerosis in apoE-knockout mice

Atherosclerosis (AS) is the key cause of many cardiovascular and cerebrovascular diseases. The inflammatory response and lipid metabolism disorders contribute to the development and progression of AS. This work aims to study the anti-inflammatory effect and mechanism of low molecular weight fucoidan (LMWF) obtained from Saccharina japonica on atherosclerosis in apoE-knockout mice. The experimental results showed that LMWF statistically decreased the levels of triglyceride (TRIG) and oxidative low-density lipoproteins (ox-LDL) and stabilized established atherosclerotic lesions. LMWF ameliorated the inflammatory response by down regulating IL-6 and by up regulating IL-10 transcriptional levels, and LMWF returned p-JNK and cyclin D1 to normal levels. Moreover, LMWF increased the mRNA level of CD11b in the aorta and suppressed the expression of CD11b in the intimal layer of the aorta. Therefore, LMWF prevented macrophages from developing into foam cells and prevented SMCs from migrating into the intimal layer of the aorta, which inhibited the formation of atherosclerotic plaques; and ameliorated the occurrence and development of AS.

Fucoidan Extracted from Undaria pinnatifida: Source for Nutraceuticals/Functional Foods

The importance of fucoidan as a functional ingredient in food, health products, and pharmaceutics is well-recognized due to its beneficial biological effects. Fucoidan is usually extracted from brown seaweeds, including Undaria pinnatifida. Fucoidan exhibits beneficial bio-activity and has antioxidant, anticancer, and anticoagulant properties. This review focuses on the biological activity of U. pinnatifida-derived fucoidan and investigates its structure⁻activity or fraction⁻activity relationship. It also describes several fucoidan extracts, along with their claimed anticancer effects. It aims to provide information and thoughts for future research such as the development of fucoidan into functional foods or nutraceuticals.

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.

Undaria pinnatifida a Rich Marine Reservoir of Nutritional and Pharmacological Potential: Insights into Growth Signaling and Apoptosis Mechanisms in Cancer

Seaweeds are an important part of diet consumed in a different part of the world such as New Zealand, Ireland, Wales, and Asian countries including Korea, China, and Japan. In addition, seaweed is nutritious sources possessing health improving effects and therapeutic potential. Recently, one of the widely eaten seaweed species Undaria pinnatifida (U. pinnatifida) has got much attention because of its pharmacological properties for the prevention of various ailments, including cancer, inflammation, and other diseases. It is rich in all essential amino acids, physiologically significant fatty acids, vitamins, minerals, and has a variety of bioactive constituents which include fucoidan, carotenoids, and fucoxanthin. The present study reviews the nutritional aspects, key bioactivities specifically focusing on anticancer potential along with apoptosis and growth signaling mechanisms of U. pinnatifida or its constituents. It exhibited anticancer effects both in vitro and in vivo studies in a variety of experimental models. Due to a variety of pharmacological properties of U. pinnatifida can not only fulfilling nutritional necessities, but it can be used for treating, curing and preventing cancer.

Purification, partial characterization and inducing tumor cell apoptosis activity of a polysaccharide from Ganoderma applanatum

In this study, a homogeneous polysaccharide (designated as GAP-3S) with an average molecular weight of 6.82×10⁵ Da was purified from Ganoderma applanatum. GAP-3S was composed of glucose, galactose, fucose and xylose in the molar ratio of 7.1:2.6:1.1:1. It could significantly inhibit the proliferation of MCF-7 cells in a dose- and time-dependent manner. Flow cytometry analysis indicated that GAP-3S could also induce cell apoptosis. Treatment of MCF-7 cells with GAP-3S lead to the collapse of mitochondrial membrane potential and the accumulation of ROS, up-regulated expression of Bax, cleavage of PARP, p-p38 and p-JNK, and the down-regulated expression of Bcl-2, PARP and p-ERK. The activities of caspase-3 and caspase-9 were also increased in GAP-3S-treated MCF-7 cells compared to untreated cells. These findings suggested that GAP-3S probably induced apoptosis in MCF-7 cells through intrinsic mitochondrial apoptosis and MAPK signaling pathways.

Fucoidan inhibits lymphangiogenesis by downregulating the expression of VEGFR3 and PROX1 in human lymphatic endothelial cells

Lymphangiogenesis is one of the promoters of tumor lymphatic metastasis. Fucoidan which is a fucose-enriched sulfated polysaccharide has effect on various pharmacological activities including anti-metastasis activity. However, the inhibitory effect of fucoidan on lymphangiogenesis remains unclear. Here, fucoidan extracted from U. pinnatifida sporophylls suppressed HLECs proliferation, migration and tube-like structure formation, and had inhibitory effect of tumor-induced lymphangiogenesis in vitro. Additionally, we found that fucoidan had a dose-dependent depressive effect on the expressions of PROX1, vascular endothelial growth factor receptor 3 (VEGFR3), NF-κB, phospho-PI3K and phospho-Akt in HLECs. Moreover, anti-lymphangiogenesis effect of fucoidan was assessed by using mouse tumor model. In summary, fucoidan inhibit tumor lymphangiogenesis and lymphatic metastasis by suppressing the NF-κB/PI3K/Akt signaling pathway through reduced levels of PROX1 and VEGFR3.

Fucoidan inhibits amyloid-β-induced toxicity in transgenic Caenorhabditis elegans by reducing the accumulation of amyloid-β and decreasing the production of reactive oxygen species

Fucoidan treatment effectively alleviates the paralyzed phenotype induced by the accumulation of Abeta in a transgenic Caenorhabditis elegans (C. elegans) Alzheimer's disease (AD) model.

Myricetin Inhibits Angiogenesis by Inducing Apoptosis and Suppressing PI3K/Akt/mTOR Signaling in Endothelial Cells

Background

Myricetin has been shown to possess potential antiangiogenic effects in endothelial cells. However, the underlying mechanisms are not fully understood. Therefore, we evaluated its antiangiogenic effects in human umbilical vascular endothelial cells (HUVECs).

Methods

HUVECs were cultured in endothelial cell growth medium-2 to induce proliferation and angiogenesis and treated with different doses of myricetin (0.25, 0.5, and 1 μM) for 24 hours. Cell proliferation was analyzed by the MTT and lactate dehydrogenase release assays; angiogenesis was determined by the tube formation assay. In addition, cell signaling pathways related to angiogenesis were investigated by Western blotting.

Results

Myricetin induced apoptosis and procaspase-3 cleavage though the induction of reactive oxygen species (ROS). It significantly inhibited cell migration, tube formation, and PI3K/Akt/mTOR signaling in HUVECs.

Conclusions

Myricetin exerts antiangiogenic effects by inducing ROS-mediated apoptosis and inhibiting PI3K/Akt/mTOR signaling in HUVECs.

The potential of brown-algae polysaccharides for the development of anticancer agents: An update on anticancer effects reported for fucoidan and laminaran

In recent decades, attention to cancer-preventive treatments and studies on the development of anticancer drugs have sharply increased owing to the increase in cancer-related death rates in every region of the world. However, due to the adverse effects of synthetic drugs, much attention has been given to the development of anticancer drugs from natural sources because of fewer side effects of natural compounds than those of synthetic drugs. Recent studies on compounds and crude extracts from marine algae have shown promising anticancer properties. Among those compounds, polysaccharides extracted from brown seaweeds play a principal role as anticancer agents. Especially, a number of studies have revealed that polysaccharides isolated from brown seaweeds, such as fucoidan and laminaran, have promising effects against different cancer cell types in vitro and in vivo. Herein, we reviewed in vitro and in vivo anticancer properties reported for fucoidan and laminaran toward various cancer cells from 2013 to 2016.

Dihydromyricetin-mediated inhibition of the Notch1 pathway induces apoptosis in QGY7701 and HepG2 hepatoma cells

AIM

To investigate whether Dihydromyricetin (DHM) inhibits cell proliferation and promotes apoptosis by downregulating Notch1 expression.

METHODS

The correlation between Notch1 and Hes1 (a Notch1 target molecule) expression in hepatoma samples was confirmed by qRT-PCR. In addition, MTT assays, flow cytometry and TUNEL analysis showed that DHM possessed strong anti-tumor properties, evidenced not only by reduced cell proliferation but also by enhanced apoptosis in QGY7701 and HepG2 hepatocellular carcinoma (HCC) cells. The expressions of Notch1, Hes1, Bcl-2 and Bax were determined by Western blot.

RESULTS

Among the tested samples (n = 64), the expression levels of Notch1 (75% of patients) and Hes1 (79.7% of patients) mRNA in tumor tissues were higher than in the normal liver tissues. There was a negative correlation between the expression of Notch1 and the degree of differentiation and positively correlated with the Alpha Fetal Protein concentration. The viability of HCC cells treated with DHM was significantly inhibited in a dose and time-dependent manner. Apoptosis was induced in HepG2 and QGY7701 cell lines following 24 h of DHM treatment. After treatment with DHM, the protein expression of Notch1 was downregulated, the apoptosis-related protein Bax was upregulated and Bcl2 was downregulated. Notch1 siRNA further enhanced the anti-tumor properties of DHM.

CONCLUSION

Notch1 is involved in the development of HCC and DHM inhibits cell proliferation and promotes apoptosis by down-regulating the expression of Notch1.

Sinularin induces oxidative stress-mediated G2/M arrest and apoptosis in oral cancer cells

Soft corals-derived natural product, sinularin, was antiproliferative against some cancers but its effect and detailed mechanism on oral cancer cells remain unclear. The subject of this study is to examine the antioral cancer effects and underlying detailed mechanisms in terms of cell viability, oxidative stress, cell cycle analysis, and apoptosis analyses. In MTS assay, sinularin dose-responsively decreased cell viability of three oral cancer cells (Ca9-22, HSC-3, and CAL 27) but only little damage to oral normal cells (HGF-1). This cell killing effect was rescued by the antioxidant N-acetylcysteine (NAC) pretreatment. Abnormal cell morphology and induction of reactive oxygen species (ROS) were found in sinularin-treated oral cancer Ca9-22 cells, however, NAC pretreatment also recovered these changes. Sinularin arrested the Ca9-22 cells at G2/M phase and dysregulated the G2/M regulatory proteins such as cdc2 and cyclin B1. Sinularin dose-responsively induced apoptosis on Ca9-22 cells in terms of flow cytometry (annexin V and pancaspase analyses) and western blotting (caspases 3, 8, 9) and poly (ADP-ribose) polymerase (PARP). These apoptotic changes of sinularin-treated Ca9-22 cells were rescued by NAC pretreatment. Taken together, sinularin induces oxidative stress-mediated antiproliferation, G2/M arrest, and apoptosis against oral cancer cells and may be a potential marine drug for antioral cancer therapy.

Fucoidan induces Toll-like receptor 4-regulated reactive oxygen species and promotes endoplasmic reticulum stress-mediated apoptosis in lung cancer

Fucoidan, a sulfated polysaccharide extracted from brown algae, exhibits anti-cancer activity. However, the effects and mechanism of fucoidan-induced apoptosis via endoplasmic reticulum (ER) stress is unclear. In this study, we demonstrated that fucoidan prevents tumorigenesis and reduces tumor size in LLC1-xenograft male C57BL/6 mice. Fucoidan induces an ER stress response by activating the PERK-ATF4-CHOP pathway, resulting in apoptotic cell death in vitro and in vivo. Furthermore, ATF4 knockdown abolishes fucoidan-induced CHOP expression and rescues cell viability. Specifically, fucoidan increases intracellular reactive oxygen species (ROS), which increase ATF4 and CHOP in lung cancer cells. Using the ROS scavenger N-acetyl-l-cysteine (NAC), we found that ROS generation is involved in fucoidan-induced ER stress-mediated apoptosis. Moreover, via Toll-like receptor 4 (TLR4) knockdown, we demonstrated that fucoidan-induced ROS and CHOP expression were attenuated. Our study is the first to identify a novel mechanism for the antitumor activity of fucoidan. We showed that fucoidan inhibits tumor viability by activating the TLR4/ROS/ER stress axis and the downstream PERK-ATF4-CHOP pathway, leading to apoptosis and suppression of lung cancer cell progression. Together, these results indicate that fucoidan is a potential preventive and therapeutic agent for lung cancer that acts via activation of ROS-dependent ER stress pathways.

Protective Effects of Fucoidan on Aβ25-35 and d-Gal-Induced Neurotoxicity in PC12 Cells and d-Gal-Induced Cognitive Dysfunction in Mice

Alzheimer's disease (AD) is a chronic neurodegenerative disease which contributes to memory loss and cognitive decline in the elderly. Fucoidan, extracted from brown algae, is a complex sulfated polysaccharide and potential bioactive compound. In this study, we investigated whether fucoidan protects PC12 cells from apoptosis induced by a combination of beta-amyloid 25-35 (Aβ25-35) and d-galactose (d-Gal), and improves learning and memory impairment in AD model mice. The results indicated that fucoidan could inhibit the release of cytochrome c from the mitochondria to cytosol and activation of caspases, and increase the expression of apoptosis inhibitor proteins (IAPs), including livin and X-linked IAP (XIAP) in PC12 cells damaged by Aβ25-35 and d-Gal-induction. Fucoidan reversed the decreased activity of acetylcholine (ACh) and choline acetyl transferase (ChAT), as well as the increased activity of acetylcholine esterase (AChE), in AD model mice induced by infusion of d-Gal. Furthermore, fucoidan improved antioxidant activity in vitro and in vivo by activation of superoxide dismutase (SOD) and glutathione (GSH). These results suggested that fucoidan could protect PC12 cells from apoptosis and ameliorate the learning and memory impairment in AD model mice, which appeared to be due to regulating the cholinergic system, reducing oxidative stress, and inhibiting the caspase-dependent apoptosis pathway.

Thapsigargin sensitizes human esophageal cancer to TRAIL-induced apoptosis via AMPK activation

Tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) is a promising anticancer agent for esophageal squamous cell carcinoma (ESCC). Forced expression of CHOP, one of the key downstream transcription factors during endoplasmic reticulum (ER) stress, upregulates the death receptor 5 (DR5) levels and promotes oxidative stress and cell death. In this study, we show that ER stress mediated by thapsigargin promoted CHOP and DR5 synthesis thus sensitizing TRAIL treatment, which induced ESCC cells apoptosis. These effects were reversed by DR5 siRNA in vitro and CHOP siRNA both in vitro and in vivo. Besides, chemically inhibition of AMPK by Compound C and AMPK siRNA weakened the anti-cancer effect of thapsigargin and TRAIL co-treatment. Therefore, our findings suggest ER stress effectively sensitizes human ESCC to TRAIL-mediated apoptosis via the TRAIL-DR5-AMPK signaling pathway, and that activation of ER stress may be beneficial for improving the efficacy of TRAIL-based anti-cancer therapy.

Sulfated polysaccharide-protein complex sensitizes doxorubicin-induced apoptosis of breast cancer cells in vitro and in vivo

The present study aimed to investigate the effect of sulfated polysaccharide-protein complex (SPPC) on the antitumor effect of doxorubicin (Dox) on MDA-MB-231 breast cancer cells in vitro and in vivo. MTT and Annexin V/propidium iodide staining assays demonstrated that SPPC selectively sensitized MDA-MB-231 cells to Dox-induced cytotoxicity. The half maximal inhibitory concentration of Dox against MDA-MB-231 cells was decreased from 5.3 to 1.5 µM when it was used concomitantly with 5 µM SPPC. SPPC potentiated Dox-induced apoptosis in breast cancer cells via the mitochondrial apoptosis signaling pathway by activating caspase-3 and caspase-9. Notably, the caspase inhibitor Z-VAD-fmk diminished the effect of SPPC on Dox-mediated apoptosis. Furthermore, combination treatment with SPPC and Dox markedly reduced the growth of breast cancer xenografts in mice. The present study demonstrated that SPPC was able to enhance the antitumor effect of Dox on breast cancer cells, thus suggesting that SPCC may be used to reduce the cumulative dose of Dox and its associated toxicities in the chemotherapy of breast cancer and other types of cancer.

Fucoidan Induces ROS-Dependent Apoptosis in 5637 Human Bladder Cancer Cells by Downregulating Telomerase Activity via Inactivation of the PI3K/Akt Signaling Pathway

Preclinical Research Fucoidan, a sulfated polysaccharide, is a compound found in various species of seaweed that has anti-viral, anti-bacterial, anti-oxidant, anti-inflammatory, and immunomodulatory activities; however, the underlying relationship between apoptosis and anti-telomerase activity has not been investigated. Here, we report that fucoidan-induced apoptosis in 5637 human bladder cancer cells was associated with an increase in the Bax/Bcl-2 ratio, the dissipation of the mitochondrial membrane potential (MMP, Δψm), and cytosolic release of cytochrome c from the mitochondria. Under the same experimental conditions, fucoidan-treatment decreased hTERT (human telomerase reverse transcriptase) expression and the transcription factors, c-myc and Sp1. This was accompanied by decreased telomerase activity. Fucoidan-treatment also suppressed activation of the PI3K/Akt signaling pathway. Inhibition of PI3K/Akt signaling enhanced fucoidan-induced apoptosis and anti-telomerase activity. Meanwhile, fucoidan treatment increased the generation of intracellular ROS, whereas the over-elimination of ROS by N-acetylcysteine, an anti-oxidant, attenuated fucoidan-induced apoptosis, inhibition of hTERT, c-myc, and Sp1 expression, and reversed fucoidan-induced inactivation of the PI3K/Akt signaling pathway. Collectively, these data indicate that the induction of apoptosis and the inhibition of telomerase activity by fucoidan are mediated via ROS-dependent inactivation of the PI3K/Akt pathway. Drug Dev Res 78 : 37-48, 2017.   © 2016 Wiley Periodicals, Inc.

A review about the development of fucoidan in antitumor activity: Progress and challenges

Fucoidan is composed of l-fucose, sulfate groups and one or more small proportions of d-xylose, d-mannose, d-galactose, l-rhamnose, arabinose, glucose, d-glucuronic acid and acetyl groups in different kinds of brown seaweeds. Many reports have demonstrated that fucoidan has antitumor activities on various cancers. However, until now, few reviews have discussed the antitumor activity of fucoidan and few reports have summarized detailed molecular mechanisms of its actions and antitumor challenges of fucoidan specially. In this review, the antitumor signaling pathway mechanisms related to fucoidan are elucidated as much detail as possible. Besides, the factors affecting the anticancer effects of fucoidan, the structural characteristics of fucoidan with anticancer activities and the challenges for the further development of fucoidan are also summarized and evaluated. The existing similar and different conclusions are summarized in an attempt to provide guidelines to help further research, and finally contribute to go into market as chemotherapeumtics.

Fucoidans in Nanomedicine

Fucoidans are widespread cost-effective sulfated marine polysaccharides which have raised interest in the scientific community over last decades for their wide spectrum of bioactivities. Unsurprisingly, nanomedicine has grasped these compounds to develop innovative therapeutic and diagnostic nanosystems. The applications of fucoidans in nanomedicine as imaging agents, drug carriers or for their intrinsic properties are reviewed here after a short presentation of the main structural data and biological properties of fucoidans. The origin and the physicochemical specifications of fucoidans are summarized in order to discuss the strategy of fucoidan-containing nanosystems in Human health. Currently, there is a need for reproducible, well characterized fucoidan fractions to ensure significant progress.

Anticancer Effect of Fucoidan on DU-145 Prostate Cancer Cells through Inhibition of PI3K/Akt and MAPK Pathway Expression

In this study, we showed that PI3K/Akt signaling mediates fucoidan’s anticancer effects on prostate cancer cells, including suppression of proliferation. Fucoidan significantly decreased viability of DU-145 cancer cells in a concentration-dependent manner as shown by MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide] assay. The drug also significantly increased chromatin condensation, which indicates apoptosis, in a concentration-dependent manner as shown by DAPI (4′,6-diamidino-2-phenylindole) staining. Fucoidan increased expression of Bax, cleaved poly-ADP ribose polymerase and cleaved caspase-9, and decreased of the Bcl-2, p-Akt, p-PI3K, p-P38, and p-ERK in a concentration-dependent manner. In vivo, fucoidan (at 5 and 10 mg/kg) significantly decreased tumor volume, and increased apoptosis as assessed by the TUNEL (terminal deoxynucleotidyl transferase dUTP nick end labeling) assay, confirming the tumor inhibitory effect. The drug also increased expression of p-Akt and p-ERK as shown by immunohistochemistry staining. Therefore, fucoidan may be a promising cancer preventive medicine due to its growth inhibitory effects and induction of apoptosis in human prostate cancer cells.

Anti-inflammatory effects of sodium alginate/gelatine porous scaffolds merged with fucoidan in murine microglial BV2 cells

Microglia are the immune cells of the central nervous system (CNS). Overexpression of inflammatory mediators by microglia can induce several neurological diseases. Thus, the underlying basic requirement for neural tissue engineering is to develop materials that exhibit little or no neuro-inflammatory effects. In this study, we have developed a method to create porous scaffolds by adding fucoidan (Fu) into porous sodium alginate (Sa)/gelatine (G) (SaGFu). For mechanical characterization, in vitro degradation, stress/strain, swelling, and pore size were measured. Furthermore, the biocompatibility was evaluated by assessing the adhesion and proliferation of BV2 microglial cells on the SaGFu porous scaffolds using scanning electron microscopy (SEM) and lactate dehydrogenase (LDH) assay, respectively. Moreover, we studied the neuro-inflammatory effects of SaGFu on BV2 microglial cells. The effect of gelatine and fucoidan content on the various properties of the scaffold was investigated and the results showed that mechanical properties increased porosity and swelling ratio with an increase in the gelatine and fucoidan, while the in vitro biodegradability decreased. The average SaGFu diameter attained by fabrication of SaGFu ranged from 60 to 120μm with high porosity (74.44%-88.30%). Cell culture using gelatine 2.0% (SaG2Fu) and 4.0% (SaG4Fu), showed good cell proliferation; more than 60-80% that with Sa alone. Following stimulation with 0.5μg/mL LPS, microglia cultured in porous SaGFu decreased their expression of nitric oxide (NO), prostaglandin E2 (PGE2), and reactive oxygen species (ROS). SaG2Fu and SaG4Fu also inhibited the activation and translocation of p65 NF-κB protein levels, resulting in reduction of NO, ROS, and PGE2 production. These results provide insights into the diverse biological effects and opens new avenues for the applications of SaGFu in neuroscience.

A novel polysaccharide from Sargassum integerrimum induces apoptosis in A549 cells and prevents angiogensis in vitro and in vivo

Many polysaccharides isolated from plants have exhibited promising antitumor activities. The aim of this study is to investigate the antitumor activity of the novel polysaccharide named SPS from Sargassum integerrimum, elucidate the underlying anticancer mechanism in a human lung cancer cell line A549, and evaluate its anti-angiogenic activity both in vitro and in vivo. The results show that SPS significantly reduces A549 cells viability in a dose- and time-dependent manner via MTT method. Flow cytometry analysis indicates that SPS could induce cell apoptosis, the loss of mitochondrial membrane potential (MMP), generation of reactive oxygen species (ROS) and G2/M phase cell cycle arrest of A549 cells. Up-regulation of the expressions of P53 and Bax, down-regulation of the expression of Bcl-2, and activation of cleaved caspase-3, caspase-9 and PARP are also detected by western blotting after the treatment of SPS. In addition, SPS inhibits the proliferation, migration and cord formation of human umbilical vein endothelial cells (HUVECs) in vitro, and prevents the vascular development of zebrafish embryos in vivo. Altogether, our data prove the anticancer and anti-angiogenesis properties of SPS, and provide further insights into the potential pharmacological application of SPS as antitumor and anti-angiogenic agent against lung cancer.

Extracellular Polymeric Substances of Aphanizomenon flos-aquae (EPS-A) Induced Apoptosis in Astrocytes of Zebrafish

In this study, extracellular polymeric substances of Aphanizomenon flos-aquae (EPS-A) were investigated in order to explore their effect on astrocytes of zebrafish and potential risk for environment. Astrocytes were treated with varying concentrations of EPS-A, the results showed that EPS-A inhibited astrocytes growth in a dose-and time-dependent manner. With the concentrations of EPS-A increasing, the adherent ability of astrocytes decreased and the number of astrocytes floating in the culture medium increased. When treated with 2.35 µg/mL EPS-A, EPS-A induced cell cycle arrest and made the collapse of mitochondrial membrane potential and then led to astrocytes apoptosis. The results suggested that EPS-A could pose a threat to zebrafish and represent risk for environment, so regularly monitoring the presence of EPS-A was very important in nutrient-rich freshwaters when A. flos-aquae blooms broke out.

Icariin displays anticancer activity against human esophageal cancer cells via regulating endoplasmic reticulum stress-mediated apoptotic signaling

In this study, we investigated the antitumor activity of icariin (ICA) in human esophageal squamous cell carcinoma (ESCC) in vitro and in vivo and explored the role of endoplasmic reticulum stress (ERS) signaling in this activity. ICA treatment resulted in a dose- and time-dependent decrease in the viability of human EC109 and TE1 ESCCs. Additionally, ICA exhibited strong antitumor activity, as evidenced by reductions in cell migration, adhesion, and intracellular glutathione (GSH) levels and by increases in the EC109 and TE1 cell apoptotic index, Caspase 9 activity, reactive oxygen species (ROS) level, and nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activity. Furthermore, ICA treatments upregulated the levels of ERS-related molecules (p-PERK, GRP78, ATF4, p-eIF2α, and CHOP) and a pro-apoptotic protein (PUMA) and simultaneously downregulated an anti-apoptotic protein (Bcl2) in the two ESCC cell lines. The downregulation of ERS signaling using eIF2α siRNA desensitized EC109 and TE1 cells to ICA treatment, and the upregulation of ERS signaling using thapsigargin sensitized EC109 and TE1 cells to ICA treatment. In summary, ERS activation may represent a mechanism of action for the anticancer activity of ICA in ESCCs, and the activation of ERS signaling may represent a novel therapeutic intervention for human esophageal cancer.

Extracellular polymeric substance from Aphanizomenon flos-aquae induces apoptosis via the mitochondrial pathway in A431 human epidermoid carcinoma cells

Extracellular polymeric substance (EPS) is a substance secreted during algal growth, which has been found to have numerous health-promoting effects. In the present study, A431 human epidermoid carcinoma cells were selected as target cells and cultivated in vitro as an experimental model to investigate the anti-cancer effect of extracellular polymeric substances from Aphanizomenon flos-aquae (EPS-A) and the possible underlying mechanism. Apoptosis- and cell cycle-associated molecules as well as the mitochondrial membrane potential of the cells were quantified using flow cytometry (FCM). FCM showed that EPS-A induced cell cycle arrest, which led to a loss of mitochondrial function of the A431 cells and an increase in necrotic and late apoptotic cells. In order to evaluate the apoptosis and cell viability, acridine orange/ethidium bromide staining was used, morphological changes were observed using fluorescence microscopy and typical apoptotic characteristics were observed. Following treatment with a high dose of EPS-A, transmission electron microscopy showed nuclear fragmentation, chromosome condensation, cell shrinkage and expansion of the endoplasmic reticulum; apoptotic bodies were also observed. In conclusion, EPS-A caused cell cycle arrest, stimulated cell apoptosis via the mitochondrial pathway and exhibited important anti-cancer activity.

Gallic acid as a selective anticancer agent that induces apoptosis in SMMC-7721 human hepatocellular carcinoma cells

Gallic acid (3,4,5-trihydroxybenzoic acid; GA) is a naturally occurring plant polyphenol, isolated from water caltrop, which has been reported to exert anticancer effects. The present study investigated the antiproliferative effects of GA on the HepG2 and SMMC-7721 human hepatocellular carcinoma (HCC) cell lines using MTT and colony formation assays. In particular, the underlying mechanism of GA-induced apoptosis in SMMC-7721 cells was studied in vitro by flow cytometry and western blotting. The results of the present study indicated that GA was capable of inhibiting the proliferation of HepG2 and SMMC-7721 cells in a time- and dose-dependent manner, as well as inducing the apoptosis of SMMC-7721 cells. GA induced caspase-3, caspase-9 and reactive oxygen species activity, elevated the expression of apoptosis regulator Bcl-2-like protein 4 and reduced the mitochondrial membrane potential in SMMC-7721 cells. When compared with HL-7702 normal human hepatocytes, GA demonstrated selective toxicity for HCC cells. In conclusion, GA is able to induce apoptosis in SMMC-7721 cells in vitro via mitochondrial-mediated pathways, and may possess the potential to be a novel therapeutic compound for use in the treatment of HCC.

Fucoidan inhibits proliferation of the SKM-1 acute myeloid leukaemia cell line via the activation of apoptotic pathways and production of reactive oxygen species

Myelodysplastic syndromes (MDS) are a heterogeneous group of myeloid disorders characterized by peripheral blood cytopenias and a high risk of progression to acute myeloid leukaemia (AML). Fucoidan, a complex sulphated polysaccharide isolated from the cell wall of brown seaweeds, has recently attracted attention for its multiple biological activities and its potential as a novel candidate for cancer therapy. In the present study, the anti‑cancer activity of fucoidan was investigated in the MDS/AML cell line SKM‑1. Fucoidan inhibited proliferation, induced apoptosis and caused G1-phase arrest of the cell cycle in SKM‑1 cells as determined by a cell counting kit 8 assay and flow cytometry. Furthermore, reverse transcription quantitative polymerase chain reaction and western blot analyses indicated that treatment with fucoidan (100 µg/ml for 48 h) activated Fas and caspase‑8 in SKM‑1 cells, which are critical for the extrinsic apoptotic pathway; furthermore, caspase‑9 was activated via decreases in phosphoinositide-3 kinase/Akt signaling as indicated by reduced levels of phosphorylated Akt, suggesting the involvement of the intrinsic apoptotic pathway. In addition, fucoidan treatment of SKM‑1 cells resulted in the generation of reactive oxygen species (ROS) as determined by staining with dichloro-dihydro-fluorescein diacetate. These results suggested that the mechanisms of the anti‑cancer effects of fucoidan in SKM‑1 are closely associated with cell cycle arrest and apoptotic cell death, which partly attributed to the activation of apoptotic pathways and accumulation of intracellular ROS. Our results demonstrated that Fucoidan inhibits proliferation and induces the apoptosis of SKM‑1 cells, which provides substantial therapeutic potential for MDS treatment.

Mitochondrial reactive oxygen species and complex II levels are associated with the outcome of hepatocellular carcinoma

In the present study, two oxidative stress parameters, reactive oxygen species (ROS) and mitochondrial respiratory complex II, were evaluated in the mitochondria of hepatocellular carcinoma (HCC) cells to determine the association between these parameters and the carcinogenesis and clinical outcome of HCC. High levels of ROS and low levels of complex II were found to be associated with reduced post-operative survival in HCC patients using the log-rank test. Furthermore, multivariate analysis confirmed that the levels of ROS [relative risk (RR)=2.867; 95% confidence interval (CI), 1.062-7.737; P=0.038] and complex II (RR=5.422; 95% CI, 1.273-23.088; P=0.022) were independent predictors for the survival of patients with HCC. Therefore, the analysis of ROS and complex II levels may provide a useful research and therapeutic tool for the prediction of HCC prognosis and treatment.

Activation and Inhibition of ATM by Phytochemicals: Awakening and Sleeping the Guardian Angel Naturally

Double-stranded breaks (DSBs) are cytotoxic DNA lesions caused by oxygen radicals, ionizing radiation, and radiomimetic chemicals. Increasing understanding of DNA damage signaling has provided an ever-expanding list of modulators reported to orchestrate DNA damage repair and ataxia telangiectasia mutated (ATM) is the master regulator and main transducer of the DSB response. Increasingly, it is being realized that DNA damage response is a synchronized and branched network that functionalizes different molecular cascades to activate special checkpoints, thus temporarily arresting progression of the cell cycle while damage is being assessed and processed. It is noteworthy that both nutrigenetics and nutrigenomics have revolutionized the field of molecular biology and rapidly accumulating experimental evidence has started to shed light on biological activities of a wide range of phytochemicals reported to modulate cell cycle, DNA repair, cell growth, differentiation and apoptosis as evidenced by cell-based studies. In this review, we have attempted to provide an overview of DNA damage signaling, how ATM signaling regulates tumor necrosis factors-related apoptosis inducing ligand (TRAIL)-induced intracellular network. We also illuminate on how resveratrol, epigallocatechin gallate, curcumin, jaceosidin, cucurbitacin, apigenin, genistein, and others trigger activation of ATM in different cancer cells as well as agents for ATM inactivation. Understanding the interplay of TRAIL-induced intracellular signaling and ATM modulation of downstream effectors is very important. This holds particularly for a reconceptualization of the apparently paradoxical roles and therapeutically targetable for enhancing the response to DNA damage-inducing therapy.

Synergistic effect of HMGB1 knockdown and cordycepin in the K562 human chronic myeloid leukemia cell line

The high-mobility group box 1 (HMGB1) protein is a DNA-binding nuclear protein, which is overexpressed in leukemia cells. Cordycepin is characterized by strong antileukemic properties and is regarded as an effective natural compound for leukemia therapy. The aim of the present study was to investigate the impact of HMGB1 knockdown and cordycepin treatment on proliferation, apoptosis, reactive oxygen species (ROS) levels and adhesion of K562 human chronic myeloid leukemia cells. The Cell Counting kit‑8 assay was used to determine the proliferation of K562 cells. The cell cycle and apoptosis of K562 cells was determined using flow cytometric analysis. In addition, a cell adhesion assay was performed. Western blotting was used to determine the protein expression of cyclooxygenase 2, Bax, receptor for advanced glycation end-products and Bcl‑2. The data collected demonstrated that HMGB1 knockdown combined with cordycepin treatment had significant anti‑proliferative and pro‑apoptotic effects. In addition, it increased the ROS levels and reduced the adhesion of K562 cells. It was also identified that HMGB1 knockdown had synergistic effects with cordycepin, which aided in accelerating apoptosis, and inhibiting proliferation and adhesion in chronic myeloid leukemia cells. These results indicated that HMGB1 may be used as a potential therapeutic target, with cordycepin having potential as an auxiliary drug. Therefore, it is suggested that HMGB1 knockdown and corycepin treatement may present a promising therapeutic strategy for leukemia.

Fucoidan Suppresses Hypoxia-Induced Lymphangiogenesis and Lymphatic Metastasis in Mouse Hepatocarcinoma

Metastasis, the greatest clinical challenge associated with cancer, is closely connected to multiple biological processes, including invasion and adhesion. The hypoxic environment in tumors is an important factor that causes tumor metastasis by activating HIF-1α. Fucoidan, extracted from brown algae, is a sulfated polysaccharide and, as a novel marine biological material, has been used to treat various disorders in China, Korea, Japan and other countries. In the present study, we demonstrated that fucoidan derived from Undaria pinnatifida sporophylls significantly inhibits the hypoxia-induced expression, nuclear translocation and activity of HIF-1α, the synthesis and secretion of VEGF-C and HGF, cell invasion and lymphatic metastasis in a mouse hepatocarcinoma Hca-F cell line. Fucoidan also suppressed lymphangiogenesis in vitro and in vivo. In addition, accompanied by a reduction in the HIF-1α nuclear translocation and activity, fucoidan significantly reduced the levels of p-PI3K, p-Akt, p-mTOR, p-ERK, NF-κB, MMP-2 and MMP-9, but increased TIMP-1 levels. These results indicate strongly that the anti-metastasis and anti-lymphangiogenesis activities of fucoidan are mediated by suppressing HIF-1α/VEGF-C, which attenuates the PI3K/Akt/mTOR signaling pathways.

Fucoidan and cancer: a multifunctional molecule with anti-tumor potential

There is a wide variety of cancer types yet, all share some common cellular and molecular behaviors. Most of the chemotherapeutic agents used in cancer treatment are designed to target common deregulated mechanisms within cancer cells. Many healthy tissues are also affected by the cytotoxic effects of these chemical agents. Fucoidan, a natural component of brown seaweed, has anti-cancer activity against various cancer types by targeting key apoptotic molecules. It also has beneficial effects as it can protect against toxicity associated with chemotherapeutic agents and radiation. Thus the synergistic effect of fucoidan with current anti-cancer agents is of considerable interest. This review discusses the mechanisms by which fucoidan retards tumor development, eradicates tumor cells and synergizes with anti-cancer chemotherapeutic agents. Challenges to the development of fucoidan as an anti-cancer agent will also be discussed.

Mekabu fucoidan: structural complexity and defensive effects against avian influenza A viruses

Fucoidan from the sporophyll (Mekabu) of brown seaweed Undaria pinnatifida (wakame) is interesting due to its various biological activities. Mekabu fucoidan (Mw ∼ 9 kDa) of this study (MF) was previously isolated and characterized by chemical and separation methods including GPC and methylation analysis (Lee, Hayashi, Hashimoto, Nakano, & Hayashi, 2004). It was found that this fucoidan composed of partially sulphated (DS ∼ 0.72) fucose and galactose at approximately equal amounts. Methylation analyses revealed complex structure of MF. However, it has been still unclear about the linkages between units and substitution patterns. To solve these structural tasks, spectroscopic methods (FTIR, FT Raman and NMR) were used in the analysis of native MF and its deesterified derivatives. According to obtained results, this polysaccharide was defined as O-acetylated sulphated fucogalactan. The defensive effects of MF were evaluated on mice infected with avian influenza A viruses (H5N3 and H7N2 subtypes); its efficacy was determined in reducing viral replication and increasing antibody production. Oral administration of MF resulted in suppressing virus yields. In addition, the production of neutralizing antibodies and mucosal IgA in the animals inoculated with the avian influenza A viruses was significantly increased. These results suggested that MF could be used for the prevention of viral infection.

Anticancer effects of different seaweeds on human colon and breast cancers

Seafoods and seaweeds represent some of the most important reservoirs of new therapeutic compounds for humans. Seaweed has been shown to have several biological activities, including anticancer activity. This review focuses on colorectal and breast cancers, which are major causes of cancer-related mortality in men and women. It also describes various compounds extracted from a range of seaweeds that have been shown to eradicate or slow the progression of cancer. Fucoidan extracted from the brown algae Fucus spp. has shown activity against both colorectal and breast cancers. Furthermore, we review the mechanisms through which these compounds can induce apoptosis in vitro and in vivo. By considering the ability of compounds present in seaweeds to act against colorectal and breast cancers, this review highlights the potential use of seaweeds as anticancer agents.