Antiangiogenic activity and direct antitumor effect from a sulfated polysaccharide isolated from seaweed

Antioxidant Activity and Inhibition of Liver Cancer Cells' Growth of Extracts from 14 Marine Macroalgae Species of the Mediterranean Sea

Macroalgae exhibit beneficial bioactivities for human health. Thus, the aim of the present study was to examine the antioxidant and anticancer potential of 14 macroalgae species' extracts, namely, Gigartina pistillata, Gigartina teedei, Gracilaria gracilis, Gracilaria sp., Gracilaria bursa pastoris, Colpomenia sinuosa, Cystoseira amentacea, Cystoseira barbata, Cystoseira compressa, Sargassum vulgare, Padina pavonica, Codium fragile, Ulva intestinalis, and Ulva rigida, from the Aegean Sea, Greece. The antioxidant activity was assessed using DPPH, ABTS^•+, ^•OH, and O₂^•- radicals' scavenging assays, reducing power (RP), and protection from ROO^•-induced DNA plasmid damage assays. Moreover, macroalgae extracts' total polyphenol contents (TPCs) were assessed. Extracts' inhibition against liver HepG2 cancer cell growth was assessed using the XTT assay. The results showed that G. teedei extract's IC₅₀ was the lowest in DPPH (0.31 ± 0.006 mg/mL), ABTS^•+ (0.02 ± 0.001 mg/mL), ^•OH (0.10 ± 0.007 mg/mL), O₂^•- (0.05 ± 0.003 mg/mL), and DNA plasmid breakage (0.038 ± 0.002 mg/mL) and exhibited the highest RP (RP_0.5AU 0.24 ± 0.019 mg/mL) and TPC (12.53 ± 0.88 mg GAE/g dw). There was also a significant correlation between antioxidant activity and TPC. P. pavonica (IC₅₀ 0.93 ± 0.006 mg/mL) exhibited the highest inhibition against HepG2 cell growth. Conclusively, some of the tested extracts exhibited significant chemopreventive properties, and so they may be used for food products.

FTIR Characterization of Sulfated Polysaccharides Obtained from Macrocystis integrifolia Algae and Verification of Their Antiangiogenic and Immunomodulatory Potency In Vitro and In Vivo

The aim of this study was to evaluate the antiangiogenic and immunomodulatory potential of sulfated polysaccharides from the marine algae Macrocystis integrifolia characterized by FTIR. The cytotoxicity of sulfated polysaccharides was evaluated using the 3-(4,5-dimethylthiazol-2-yl) -2,5-diphenyltetrazolium bromide (MTT) assay. Antiangiogenic activity was evaluated using the chicken chorioallantoic membrane (CAM) assay. Immunomodulatory activity was determined on macrophage functionality and allergic response. The results showed that sulfated polysaccharides significantly decreased angiogenesis in chicken chorioallantoic membranes (p < 0.05). Likewise, they inhibited in vivo chemotaxis and in vitro phagocytosis, the transcription process of genes that code the enzymes cyclooxygenase-1 (COX-1), cyclooxygenase-2 (COX-2) and nitric oxide synthase-2 (NOS-2) and the nuclear factor kappa-light chain enhancer of activated B cells (NF-κB), showing immunomodulatory properties on the allergic response, as well as an in vivo inhibitory effect in the ovalbumin-induced inflammatory allergy model (OVA) and inhibited lymphocyte proliferation specific to the OVA antigen in immunized mice. Finally, these compounds inhibited the histamine-induced skin reaction in rats, the production of immunoglobulin E (IgE) in mice, and the passive response to skin anaphylaxis in rats. Therefore, the results of this research showed the potential of these compounds to be a promising source for the development of antiangiogenic and immunomodulatory drugs.

Rich d-Fructose-Containing Polysaccharide Isolated from Myxopyrum smilacifolium Roots toward a Superior Antioxidant Biomaterial

The presented study attempts to unveil and evaluate the antioxidant activity of a novel heteropolysaccharide separated from the roots of Myxopyrum smilacifolium (denoted as PS-MSR). The molecular weight of PS-MSR is found to be 1.88 × 10⁴ Da and contains two principal sugars, which are d-glucose and d-fructose, in the backbone. Decoding the structure of the obtained PS-MSR sample has disclosed a novel polysaccharide for the first time. Indeed, the PS-MSR is composed of (1 → 3)-linked glucosyl units and (2 → 3)-linked fructosyl units. In addition, the 1D and 2D NMR spectra of the PS-MSR sample display the repeating unit of the isolated polysaccharide, [→3)-α-d-Glcp-(1 → 3)-β-d-Frucf-(2 → 3)-β-d-Frucf-2 → 3)-)-β-d-Frucf-β-(2→] _n . Interestingly, the PS-MSR sample exhibits outstanding antioxidant activity, signifying the potential utilization of the explored polysaccharide for antioxidant-based material.

Advances in anti-cancer effects and underlying mechanisms of marine algae polysaccharides

Cancer is a leading cause of death in both developing and developed countries. With the increase in the average global life expectancy, it has become a major health problem and burden for most public healthcare systems worldwide. Due to the fewer side effects of natural compounds than of chemotherapeutic drugs, increasing scientific attention is being focused on the development of anti-cancer drugs derived from natural sources. Marine algae are an interesting source of functional compounds with diverse health-promoting activities. Among these compounds, polysaccharides have attracted considerable interest for many years because of their excellent anti-cancer abilities. They improve the efficacy of conventional chemotherapeutic drugs with relatively low toxicity to normal human cells. However, there are few reviews summarising the unique anti-cancer effects and underlying mechanisms of marine algae polysaccharides (MAPs). Thus, the current review focuses on updating the advances in the discovery and evaluation of MAPs with anti-cancer properties and the elucidation of their mechanisms of action, including the signalling pathways involved. This review aims to provide a deeper understanding of the anti-cancer functions of the natural compounds derived from medicinal marine algae and thereby offer a new perspective on cancer prevention and therapy with high effectiveness and safety.

Phlorotannins of the Brown Algae Sargassum vulgare from the Mediterranean Sea Coast

Brown seaweeds are a good source of bioactive compounds, particularly of phlorotannins, which may exert a wide spectrum of pharmacological properties. In the present study, phlorotannins of S. vulgare were extracted using a 70% acetone solution and the crude extract was further purified through liquid–liquid partition, giving rise to n-hexane, ethyl acetate and aqueous residue fractions. The crude extract and the purified fractions were evaluated for potential antioxidant abilities as well as for inhibitory potential towards the digestive enzymes α-amylase and pancreatic lipase, and anti-inflammatory potential through the hindering of albumin denaturation. Overall, the ethyl acetate fraction was the richest in phlorotannins (9.4 ± 0.03 mg PGE/g) and was also the most promising regarding the tested bioactive properties. Of note, its inhibitory potential towards α-amylase was about nine times that of the commercial drug acarbose and its inhibitory activity against high temperature-induced protein denaturation was superior to that of the non-steroidal drug ketoprofen. According to UHPLC-DAD-ESI-MS/MS analysis, this fraction contained a range of phlorotannins with at least six units of phloroglucinol, including dibenzodioxine-1,3,6,8-tetraol, fuhalol, pentaphlorethol, fucopentaphlorethol and dihydroxypentafuhalol, in addition to several less common phlorotannin sulfate derivatives.

Cancer-fighting potentials of algal polysaccharides as nutraceuticals

Cancer has been listed as one of the world's five incurable diseases by the World Health Organization and causes tens of thousands of deaths every year. Unfortunately, anticancer agents either show limited efficacy or show serious side effects. The algae possess high nutritional value and their polysaccharides have a variety of biological activities, especially anti-cancer and immunomodulatory properties. Algal polysaccharides exert anti-cancer effects by inducing apoptosis, cell cycle arrest, anti-angiogenesis, and regulating intestinal flora and immune function. Algal polysaccharides can be combined with nanoparticles and other drugs to reduce the side effects caused by chemotherapy and increase the anticancer effects. This review shows the signal pathways related to the anti-cancer mechanisms of algal polysaccharides, including their influence on intestinal flora and immune regulation, the application of nanoparticles, and the effects on combination therapy and clinical trials of cancer treatments.

Bioactive Metabolites from Marine Algae as Potent Pharmacophores against Oxidative Stress-Associated Human Diseases: A Comprehensive Review

In addition to cancer and diabetes, inflammatory and ROS-related diseases represent one of the major health problems worldwide. Currently, several synthetic drugs are used to reduce oxidative stress; nevertheless, these approaches often have side effects. Therefore, to overcome these issues, the search for alternative therapies has gained importance in recent times. Natural bioactive compounds have represented, and they still do, an important source of drugs with high therapeutic efficacy. In the ''synthetic'' era, terrestrial and aquatic photosynthetic organisms have been shown to be an essential source of natural compounds, some of which might play a leading role in pharmaceutical drug development. Marine organisms constitute nearly half of the worldwide biodiversity. In the marine environment, algae, seaweeds, and seagrasses are the first reported sources of marine natural products for discovering novel pharmacophores. The algal bioactive compounds are a potential source of novel antioxidant and anticancer (through modulation of the cell cycle, metastasis, and apoptosis) compounds. Secondary metabolites in marine Algae, such as phenolic acids, flavonoids, and tannins, could have great therapeutic implications against several diseases. In this context, this review focuses on the diversity of functional compounds extracted from algae and their potential beneficial effects in fighting cancer, diabetes, and inflammatory diseases.

Extraction, Purification, Characterization, and Antiangiogenic Activity of Acidic Polysaccharide from Buddleja officinalis

Firstly, optimal parameters of crude polysaccharide from Buddleja officinalis were obtained as follows: ratio of water to raw material of 26 : 1, ultrasonic power of 240 W, ultrasonic time of 45 min, and ultrasonic temperature of 62°C. Secondly, acidic polysaccharide (APBOM) from Buddleja officinalis was successfully acquired with the yield of 9.57% by using DEAE-52 cellulose and Sephadex G-100 gel column chromatography. Then, we found that total polysaccharide content of APBOM was 94.37% with a sulfuric acid group of 1.68%, uronic acid content of 17.41%, and average molecular weight of 165.4 kDa. Finally, APBOM was confirmed to have significant antiangiogenic effects.

Seaweed Porphyra yezoensis polysaccharides with different molecular weights inhibit hydroxyapatite damage and osteoblast differentiation of A7R5 cells

Vascular calcification (VC) is a common pathological manifestation in patients with cardiovascular diseases, leading to high mortality in patients with chronic kidney diseases. The deposition of hydroxyapatite (HAP) crystals on vascular smooth muscle cells leads to cell damage, which promotes osteogenic transformation. In this study, four different molecular weights (MWs ) of Porphyra yezoensis polysaccharides (PYP1, PYP2, PYP3, and PYP4 with MWs of 576, 49.5, 12.6, and 4.02 kDa, respectively) were used to coat HAP, and the differences in toxicity and calcification of HAP on A7R5 cells before and after coating were studied. The results showed that PYPs could effectively reduce HAP damage to the A7R5 cells. Under the protection of PYPs, cell viability increased and lactate dehydrogenase release, active oxygen level, and cell necrosis rate decreased; also, the amount of the HAP crystals adhering to cell surfaces and entering cells decreased. PYPs with low molecular weights presented better protective effects than high-molecular-weight PYPs. PYPs also inhibited the osteogenic transformation of the A7R5 cells induced by HAP and decreased alkaline phosphatase (ALP) activity and expressions of bone/chondrocyte phenotype genes (runt-related factor 2, ALP, osteopontin, and osteocalcin). In the adenine-induced chronic renal failure (CRF) mouse VC model, PYP4 was found to obviously inhibit the aortic calcium level, and it also inhibited the serum creatinine, serum phosphorus and serum BUN levels. PYP4 (least molecular weight) showed the best inhibitory effect on calcification and may be considered as a candidate drug with therapeutic potential for inhibiting cellular damage and osteoblast differentiation induced by the HAP crystals.

M1 Polarization but Anti-LPS-Induced Inflammation and Anti-MCF-7 Breast Cancer Cell Growth Effects of Five Selected Polysaccharides

Five potential polysaccharides from guava seed (GSPS), common buckwheat (CBPS), bitter buckwheat (BBPS), red Formosa lambsquarters (RFLPS), and yellow Formosa lambsquarters (YFLPS) were selected to measure their effects on mouse peritoneal macrophages in the absence or presence of lipopolysaccharide (LPS). Macrophage-conditioned media (MCM) in the absence or presence of 5 selected polysaccharides were prepared to treat MCF-7 cells. The cell viability was determined using 3-(4,5-dimethylthiazol-2-diphenyl)-2,5-tetrazolium bromide (MTT) assay. Proinflammatory (also known as M1 type) (interleukin- (IL-) 1β, IL-6 and tumor necrosis factor- (TNF-) α) and anti-inflammatory (also known as M2 type) (IL-10) cytokines secreted by macrophages were determined using ELISA. The relationship between MCF-7 cell growth and M1/M2 cytokine secretion profiles in the corresponding MCM were delineated. The results showed that 5 selected polysaccharides, except BBPS, significantly (P < 0.05) and dose-dependently increased M1 (IL-1β + IL-6 + TNF-α)/M2 (IL-10) cytokine secretion ratios by macrophages in the absence of LPS, suggesting that four selected polysaccharides have M1 polarization property. However, all of 5 selected polysaccharides significantly (P < 0.05) decreased proinflammatory (IL-1β + IL-6 + TNF-α)/anti-inflammatory (IL-10) cytokine secretion ratios by LPS-stimulated macrophages, exhibiting that all of the 5 selected polysaccharides, particularly GSPS, have anti-inflammatory potential. All MCM prepared with these selected polysaccharides (except YFLPS) significantly enhanced their inhibitory effects on MCF-7 cell growth. A negative correlation was noted between MCF-7 cell viabilities and M1/M2 cytokine secretion ratios ((IL-6 + TNF-α)/IL-10) in the corresponding MCM, suggesting that increases in M1 macrophages in the tumor microenvironment might inhibit MCF-7 cell growth. Particular polysaccharides including RFLPS, GSPS, YFLPS, and CBPS may increase the percentage of M1 macrophages in the tumor environment and further inhibit MCF-7 cell growth via immunotherapy.

Pharmacologic Application Potentials of Sulfated Polysaccharide from Marine Algae

With the advent of exploration in finding new sources for treating different diseases, one possible natural source is from marine algae. Having an array of potential benefits, researchers are interested in the components which comprise one of these activities. This can lead to the isolation of active compounds with biological activities, such as antioxidation of free radicals, anti-inflammation, antiproliferation of cancer cells, and anticoagulant to name a few. One of the compounds that are isolated from marine algae are sulfated polysaccharides (SPs). SPs are complex heterogenous natural polymers with an abundance found in different species of marine algae. Marine algae are known to be one of the most important sources of SPs, and depending on the species, its chemical structure varies. This variety has important physical and chemical components and functions which has gained the attention of researchers as this contributes to the many facets of its pharmacologic activity. In this review, recent pharmacologic application potentials and updates on the use of SPs from marine algae are discussed.

Production of Bioactive Compounds from the Sulfated Polysaccharides Extracts of Ulva lactuca: Post-Extraction Enzymatic Hydrolysis Followed by Ion-Exchange Chromatographic Fractionation

This paper describes a novel combined post-extraction process for obtaining bioactive compounds from the aqueous high molecular weight sulfated polysaccharides (SPs) extracts of the green algae, Ulva lactuca. After extracting the SPs, they were enzymatically hydrolyzed then the hydrolysate (V45) was fractionated into eight different molecular weight fractions (F1–F8) using ion exchange chromatography. Crude SPs together with V45 and (F1–F8) were examined for their carbohydrate, protein, and sulfate contents. In addition, their degree of polymerization (DP) was estimated and they were characterized by Fourier Transform Infrared Spectroscopy (FTIR). Fractions S1, F4, F5, and F8 showed promising antioxidant and antitumor activities in vitro. In particular, the remarkable antitumor activity of F5 on three types of cancer cell lines could be attributed to its comparable contents of protein, carbohydrate, and sulfate, in addition to its comparable contents of rhamnose and glucuronic acid, and the same for glucose and arabinose. F5 also possessed the highest Hill coefficient among the four promising fractions indicating a higher degree of cooperativity in ligand binding. Other influencing factors including DP, composition, and type of characteristic functional groups were also discussed. The implications of this work could potentially benefit the industries of food supplements and pharmaceuticals.

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.

Anticancer activity of seaweeds

Cancer is a major health problem worldwide and still lacks fully effective treatments. Therefore, alternative therapies, using natural products, have been proposed. Marine algae are an important component of the marine environment, with high biodiversity, and contain a huge number of functional compounds, including terpenes, polyphenols, phlorotannins, and polysaccharides, among others. These compounds have complex structures that have shown several biological activities, including anticancer activity, using in vitro and in vivo models. Moreover, seaweed-derived compounds target important molecules that regulate cancer processes. Here, we review our current understanding of the anticancer activity of seaweeds.

Anti-Vasculogenic Activity of a Polysaccharide Derived from Brittle Star via Inhibition of VEGF, Paxillin and MMP-9

Background: Bioactive compounds such as terpenoids, chondroitin sulfate, and polysaccharides with added value can be found in prestine marine creatures. These compounds often do have highly valuable therapeutic applications such as being antioxidant, antitumorogenic, anti-inflammatory and anti-angiogenic. For the latter, varieties of angiogenesis factors can suppress this issue within the bodily tissues. Objectives: The anti-angiogenic and anti-metastatic capacity of a polysaccharide derived from brittle star was investigated. Material and Methods: The anti-proliferative effect of derived polysaccharide on umbilical vein endothelial cells (HUVEC) was measured using MTT (dimethyl thiazol-2-yl]-2,5-diphenyl tetrazolium bromide) assay. The anti-angiogenic effect of the isolated polysaccharide was examined by Chorioallantoic membrane (CAM) assay. The transcriptional expression of VEGF (Vascular Endothelial Growth Factor) was evaluated by Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). The anti-metastatic activity was investigated via scratch-wound healing assay. The levels of Paxillin and Matrix Metalloproteinase-9 (MMP-9) expression were analyzed by RT-PCR. Statistical analysis and mean comparisons (p< 0.05) were carried out by SPSS 16. Results: Our results elucidated that the brittle star isolated polysaccharide exerted a dose dependent cytotoxic effect on the HUVEC endothelial cells. The CAM assay exhibited potent anti-angiogenic activity in vivo. The RT-PCR analysis showed that the extracted polysaccharide (40, 60 µg.mL^-1) down-regulated the VEGF expression. Further, the diminished attachment of endothelial cells demonstrated that the anti-invasiveness of the derived polysaccharide (25, 50 µg.mL^-1) was administrated via down-regulation of paxillin and MMP-9 mRNA expression. Conclusions: Taken together, these results indicated that the polysaccharide extracted from brittle star was able to decrease the viability of the HUVEC cells, to suppress angiogenesis, and possibly act as a natural anti-angiogenic and anti-metastatic marine organic compound against angiogenesis related pathologies.

Amelioration of Dalton's lymphoma-induced angiogenesis by melatonin

For tumor to grow beyond 1-2 mm³ size, tumor recruits new blood vessels referred as angiogenesis; therefore, targeting angiogenesis can be a promising strategy to suppress cancer progression. In this study, in order to develop a good angiogenesis model, we investigated effect of Dalton's lymphoma on angiogenesis and further monitored the role of melatonin on regulation of angiogenesis. To evaluate angiogenesis, endothelial cells were isolated from main thoracic aorta and cultured in vitro in the presence or absence of Dalton's lymphoma supplemented with or without melatonin to monitor their role on its proliferation and migration, a hallmark of angiogenesis. Chick chorioallantoic membrane as well as mice mesentery which allows in vivo studies of tumor angiogenesis and testing of anti-angiogenic molecules was used to validate the in vitro analysis. To further extend our understanding about the regulation of the angiogenesis, we evaluated expression of tissue inhibitor of metalloproteinases 3, vascular endothelial growth factor, vascular endothelial growth factor receptor, and fibroblast growth factor in Dalton's lymphoma cells and mesentery by semiquantitative and quantitative reverse transcription polymerase chain reaction analysis. Dalton's lymphoma ascites induced significant increase in endothelial cell proliferation, migration, and sprouting of the tertiary branching in chorioallantoic membrane and mesentery of Dalton's lymphoma-bearing mice, whereas melatonin treatment led to their inhibition in a dose-dependent manner. Semiquantitative and quantitative reverse transcription polymerase chain reaction analysis of melatonin-treated Dalton's lymphoma cells and mesentery tissue clearly demonstrated restoration of angiogenesis-related genes tissue inhibitor of metalloproteinases 3 and reduction of vascular endothelial growth factor, vascular endothelial growth factor receptor, and fibroblast growth factor messenger RNA expression. Taken together, our results strongly demonstrate that Dalton's lymphoma provides pro-angiogenic environment leading to significant increase in angiogenesis, and further melatonin treatment reduced the Dalton's lymphoma ascites-induced angiogenesis implying that Dalton's lymphoma can serve as a very good model to study angiogenesis as well as for screening of drugs that can target angiogenesis.

The inhibitory effect of anti- tumor polysaccharide from Punica granatum on metastasis

Galactomannan (PSP001) isolated from the fruit rind of Punica granatum was demonstrated as an excellent antioxidant, immunomodulatory and anticancer agent both in vitro and in vivo models. Since the most lethal and debilitating attribute of cancer cells is their ability to evolve to a state of malignancy, with key features like increased angiogenesis, invasion, migration, colony formation, and metastasis, the present study focused on evaluating the effects of the galactomannan on tumor and malignancy. PSP001 effectively reduced the neovascularization in chick embryos highlighting its potential as an angiogenic inhibitor. Furthermore, the invasion, migration and clonogenic capacity of human and murine cancer cells were dramatically inhibited by PSP001. Evaluation of the molecular mechanism of its unique potential revealed the down regulation of key players including VEGF, MMP-2, and MMP-9 with marked elevation of TIMP-1 and TIMP-2. The anti-metastatic potential of PSP001 tested in pulmonary metastasis C57BL/6 mice model deciphered the combinatorial administration with vincristine deliberated better survival rates and decreased metastatic index. The angiogenic inhibition potential of PSP001 was further proved with peritoneal angiogenesis assay in BALB/c mice ascitic tumor model. The outcomes of the current investigation highlight the mode of action of antitumor galactomannan in the reduction of tumor malignancy.

Repair Effect of Seaweed Polysaccharides with Different Contents of Sulfate Group and Molecular Weights on Damaged HK-2 Cells

The structure⁻activity relationships and repair mechanism of six low-molecular-weight seaweed polysaccharides (SPSs) on oxalate-induced damaged human kidney proximal tubular epithelial cells (HK-2) were investigated. These SPSs included Laminaria japonica polysaccharide, degraded Porphyra yezoensis polysaccharide, degraded Gracilaria lemaneiformis polysaccharide, degraded Sargassum fusiforme polysaccharide, Eucheuma gelatinae polysaccharide, and degraded Undaria pinnatifida polysaccharide. These SPSs have a narrow difference of molecular weight (from 1968 to 4020 Da) after degradation by controlling H₂O₂ concentration. The sulfate group (⁻SO₃H) content of the six SPSs was 21.7%, 17.9%, 13.3%, 8.2%, 7.0%, and 5.5%, respectively, and the ⁻COOH contents varied between 1.0% to 1.7%. After degradation, no significant difference was observed in the contents of characteristic ⁻SO₃H and ⁻COOH groups of polysaccharides. The repair effect of polysaccharides was determined using cell-viability test by CCK-8 assay and cell-morphology test by hematoxylin-eosin staining. The results revealed that these SPSs within 0.1⁻100 μg/mL did not express cytotoxicity in HK-2 cells, and each polysaccharide had a repair effect on oxalate-induced damaged HK-2 cells. Simultaneously, the content of polysaccharide ⁻SO₃H was positively correlated with repair ability. Furthermore, the low-molecular-weight degraded polysaccharides showed better repair activity on damaged HK-2 cells than their undegraded counterpart. Our results can provide reference for inhibiting the formation of kidney stones and for developing original anti-stone polysaccharide drugs.

Alpha-amylase inhibitory activity and sterol composition of the marine algae, Sargassum glaucescens

BACKGROUND

Sargassum species (phaeophyceae) are economically important brown algae in southern parts of Iran. Sargassum is mainly harvested as a row material in alginate production industries and is a source of plant foods or plant bio-stimulants even a component of animal foods.

OBJECTIVE

In this study, Sargassum glaucescens, collected from the seashore of Chabahar, was employed for phytochemical and biological evaluations.

MATERIALS AND METHODS

For that purpose, the dried algae was extracted by methanol and subjected to different chromatographic separation methods.

RESULTS

Six sterols, fucosterol (1), 24(S)-hydroxy-24-vinylcholesterol (2), 24(R)-hydroxy-24-vinylcholesterol (3), stigmasterol (4), β-sitosterol (5) and cholesterol (6) were identified by spectroscopic methods including (1)H-NMR, (13)C-NMR and mass spectroscopy. In vitro alpha-amylase inhibitory test was performed on the methanolic extract and the results revealed a potent inhibition (IC50 = 8.9 ± 2.4 mg/mL) of the enzyme compared to acarbose as a positive control.

CONCLUSION

Various biological activities and distribution of sterols in Sargassum genus have been critically reviewed here. The results concluded that these algae are a good candidate for further anti-diabetic investigations in animals and human.

Alginate-polyester comacromer based hydrogels as physiochemically and biologically favorable entities for cardiac tissue engineering

The physiochemical and biological responses of tissue engineering hydrogels are crucial in determining their desired performance. A hybrid comacromer was synthesized by copolymerizing alginate and poly(mannitol fumarate-co-sebacate) (pFMSA). Three bimodal hydrogels pFMSA-AA, pFMSA-MA and pFMSA-NMBA were synthesized by crosslinking with Ca(2+) and vinyl monomers acrylic acid (AA), methacrylic acid (MA) and N,N'-methylene bisacrylamide (NMBA), respectively. Though all the hydrogels were cytocompatible and exhibited a normal cell cycle profile, pFMSA-AA exhibited superior physiochemical properties viz non-freezable water content (58.34%) and water absorption per unit mass (0.97 g water/g gel) and pore length (19.92±3.91 μm) in comparing with other two hydrogels. The increased non-freezable water content and water absorption of pFMSA-AA hydrogels greatly influenced its biological performance, which was evident from long-term viability assay and cell cycle proliferation. The physiochemical and biological favorability of pFMSA-AA hydrogels signifies its suitability for cardiac tissue engineering.

Sulfated Galactan from Palisada flagellifera Inhibits Toxic Effects of Lachesis muta Snake Venom

In Brazil, snakebites are a public health problem and accidents caused by Lachesis muta have the highest mortality index. Envenomation by L. muta is characterized by systemic (hypotension, bleeding and renal failure) and local effects (necrosis, pain and edema). The treatment to reverse the evolution of all the toxic effects is performed by injection of antivenom. However, such therapy does not effectively neutralize tissue damage or any other local effect, since in most cases victims delay seeking appropriate medical care. In this way, alternative therapies are in demand, and molecules from natural sources have been exhaustively tested. In this paper, we analyzed the inhibitory effect of a sulfated galactan obtained from the red seaweed Palisada flagellifera against some toxic activities of L. muta venom. Incubation of sulfated galactan with venom resulted in inhibition of hemolysis, coagulation, proteolysis, edema and hemorrhage. Neutralization of hemorrhage was also observed when the galactan was administered after or before the venom injection; thus mimicking a real in vivo situation. Moreover, the galactan blocked the edema caused by a phospholipase A₂ isolated from the same venom. Therefore, the galactan from P. flagellifera may represent a promising tool to treat envenomation by L. muta as a coadjuvant for the conventional antivenom.

Modulating the SDF-1/CXCL12-induced cancer cell growth and adhesion by sulfated K5 polysaccharides in vitro

Stromal cell-derived factor-1 (SDF-1)/chemokine (CXC motif) ligand 12 (CXCL12) is involved in the process of tumor progression. Sulfated K5 polysaccharides have shown anti-cancer activity by acting on multiple targets, though it remains unclear whether sulfated K5 polysaccharides would disrupt SDF-1/CXCL12-stimulated cancer biology. This study aimed to investigate the effects of sulfated K5 polysaccharides on cell growth, adhesion in murine B16 melanoma cells and the underlying mechanism by targeting SDF-1/CXCL12. Results indicated that K5-NS,OS inhibited the proliferation of B16 melanoma cells, induced the cell cycle arrest mainly at the G0/G1 phase, and suppressed cancer cell proliferation or adhesion induced by SDF-1/CXCL12. It was possible that K5-NS,OS appeared to interact with CXCL12 and block the subsequent biological functions. This work suggests that the existence of O- and N-sulfate groups is more effective in targeting CXCL12 and exhibiting anti-cancer activity.

Effects of Hyriopsis cumingii polysaccharides on angiogenesis, macrophage chemotaxis, proliferation and phagocytosis

Hyriopsis cumingii polysaccharides (HCPS) showed anti-angiogenic activity and promoting effects on the chemotaxis, proliferation and phagocytosis of peritoneal macrophage.

Anti-proliferative and angio-suppressive effect of Stoechospermum marginatum (C. Agardh) Kutzing extract using various experimental models

BACKGROUND/OBJECTIVES

Abundant consumption of seaweeds in the diet is epidemiologically linked to the reduction in risk of developing cancer. In larger cases, however, identification of particular seaweeds that are accountable for these effects is still lacking, hindering the recognition of competent dietary-based chemo preventive approaches. The aim of this research was to establish the antiproliferative potency and angiosuppressive mode of action of Stoechospermum marginatum seaweed methanolic extract using various experimental models.

MATERIALS/METHODS

Among the 15 seaweeds screened for antiproliferative activity against Ehrlich ascites tumor (EAT) cell line, Stoechospermum marginatum extract (SME) was found to be the most promising. Therefore, it was further investigated for its anti-proliferative activity in-vitro against choriocarcinoma (BeWo) and non-transformed Human embryonic kidney (HEK 293) cells, and for its anti-migratory/tube formation activity against HUVEC cells in-vitro. Subsequently, the angiosuppressive activity of S. marginatum was established by inhibition of angiogenesis in in-vivo (peritoneal angiogenesis and chorioallantoic membrane assay) and ex-vivo (rat cornea assay) models.

RESULTS

Most brown seaweed extracts inhibited the proliferation of EAT cells, while green and red seaweed extracts were much less effective. According to the results, SME selectively inhibited proliferation of BeWo cells in-vitro in a dose-dependent manner, but had a lesser effect on HEK 293 cells. SME also suppressed the migration and tube formation of HUVEC cells in-vitro. In addition, SME was able to suppress VEGF-induced angiogenesis in the chorio allantoic membrane, rat cornea, and tumor induced angiogenesis in the peritoneum of EAT bearing mice. A decrease in the microvessel density count and CD31 antigen staining of treated mice peritoneum provided further evidence of its angiosuppressive activity.

CONCLUSIONS

Altogether, the data underline that VEGF mediated angiogenesis is the target for the angiosuppressive action of SME and could potentially be useful in cancer prevention or treatment involving stimulated angiogenesis.