Determination of Arsenic in Algae – Results of an Interlaboratory Trial: Determination of Arsenic Species in the Water-Soluble Fraction

Seven algae samples, five purchased from food stores and two reference algae (BCR 279 Sea Lettuce) were distributed as blind samples to 13 laboratories from which five labs attempted a full characterisation of the water-soluble fraction with respect to their arsenic species. The extraction efficiency is largely dependant on the algae and varied from 3% to 96%. Besides inorganic arsenic (mainly as As^(V)) DMA^(V) and, in particular, several arsenosugars were identified in all samples. From the five labs, three labs gave agreeable results in respect of the arsenic species identification and its quantification, although different chromatographic methods were used. Different Hijiki samples seem to contain largely different arsenic concentration (67–113 mg As/kg) which may also have an influence on the distribution of inorganic arsenic and arsenosugars.     

Biochemical and Anti-proliferative activities of seven abundant tropical red seaweeds confirm nutraceutical potential of Grateloupia indica

Seaweeds are being used as food items in Asian countries from ancient times. Seaweeds mainly grow in intertidal zone and survive extreme environmental conditions and thus have developed metabolites, which help them survive in such conditions. Red seaweeds have proven to be rich in compounds, which are antioxidant and having many other health benefits. In this study, seven most abundantly grown red seaweeds, Gracilaria corticata (GC), Grateloupia indica (GI), Kappaphycus alvarezii (KA), Solieria robusta (SR), Amphiroa anceps (AA), Halymenia porphyriformis (HP), and Sarconema scinaioides (SS) were collected from Saurashtra coast of Arabian Sea. Harvested seaweeds were subjected to metabolite profiling, flavonoid and phenolic content analysis, different biological activities including radical scavenging, antioxidant, reducing and proliferation inhibition. Overall, GI was found to contain high contents (flavonoid and phenolic), biological activities and proliferation inhibition. Study confirms nutraceutical potential of red seaweed Grateloupia indica to be explored further for the bioactive compound or to be used as functional food.     

Application of Carrageenan extract from red seaweed (Rhodophyta) in cosmetic products: A review

Cosmetic industries have expanded globally and will continue to increase as there are consumers. Nowadays, the interest starts to incline towards cosmetics formulated using plant-based ingredients. Marine plants such as seaweed possess numerous natural polysaccharides. Carrageenan is one of the compounds that can be extracted from red seaweed (Rhodophyta). This natural polysaccharide is widely known to act as a thickener, stabilizer, and water-binding agent as well as have diverse biological activities that make it a suitable active ingredient in cosmetic products. The review paper is organized by starting with discussing the significant aspects related to carrageenan which are the source, structure, as well as general and biological properties of carrageenan that make it appropriate to be applied in cosmetics. This paper also highlighted the applications of carrageenan in cosmetics, followed by the extraction method and instrument used.     

An Exploration of Seaweed Polysaccharides Stimulating Denitrifying Bacteria for Safer Nitrate Removal

Excessive use of nitrogen fertilizer in intensively managed agriculture has resulted in abundant accumulation of nitrate in soil, which limits agriculture sustainability. How to reduce nitrate content is the key to alleviate secondary soil salinization. However, the microorganisms used in soil remediation cause some problems such as weak efficiency and short survival time. In this study, seaweed polysaccharides were used as stimulant to promote the rapid growth and safer nitrate removal of denitrifying bacteria. Firstly, the growth rate and NO₃⁻-N removal capacity of three kinds of denitrifying bacteria, Bacillus subtilis (BS), Pseudomonas stutzeri (PS) and Pseudomonas putida (PP), were compared. The results showed that Bacillus subtilis (BS) had a faster growth rate and stronger nitrate removal ability. We then studied the effects of Enteromorpha linza polysaccharides (EP), carrageenan (CA), and sodium alginate (AL) on growth and denitrification performance of Bacillus subtilis (BS). The results showed that seaweed polysaccharides obviously promoted the growth of Bacillus subtilis (BS), and accelerated the reduction of NO₃⁻-N. More importantly, the increased NH₄⁺-N content could avoid excessive loss of nitrogen, and less NO₂⁻-N accumulation could avoid toxic effects on plants. This new strategy of using denitrifying bacteria for safely remediating secondary soil salinization has a great significance.     

我国海藻抗风浪养殖研究进展

人工栽培海藻是获得大量海藻产品的最有效手段,是弥补由于过度采撷而面临海藻自然资源枯竭的重要途径,对维持海洋生态系统健康具有重要意义。鉴于目前海藻养殖设施往往要经受不同程度的风浪冲击,遭到损坏,给养殖者带来极大的损失,加之养殖空间的限制,发展海藻抗风浪养殖迫在眉急,以减少风浪给海藻养殖带来的灾害,拓展养殖区域。概述了我国大型海藻养殖的方式、存在的问题及抗风浪养殖的研究进展,并对其市场前景进行了分析,以期为该技术的深入研究和开发利用提供参考。     

Chemical,Nutrient and Physicochemical Properties of Brown Seaweed,Sargassum polycystum C. Agardh (Phaeophyceae) Collected from Port Dickson,Peninsular Malaysia

Recent increased interest in seaweed is motivated by attention generated in their bioactive components that have potential applications in the functional food and nutraceutical industries. In the present study, nutritional composition, metabolite profiles, phytochemical screening and physicochemical properties of freeze-dried brown seaweed, Sargassum polycystum were evaluated. Results showed that the S. polycystum had protein content of 8.65 ± 1.06%, lipid of 3.42 ± 0.01%, carbohydrate of 36.55 ± 1.09% and total dietary fibre content of 2.75 ± 0.58% on dry weight basis. The mineral content of S. polycystum including Na, K, Ca, Mg Fe, Se and Mn were 8876.45 ± 0.47, 1711.05 ± 0.07, 1079.75 ± 0.30, 213.85 ± 0.02, 277.6 ± 0.12, 4.70 ± 0.00 and 4.45 ± 0.00 mg 100/g DW, respectively. Total carotenoid, chlorophyll a and b content in S. polycystum were detected at 45.28 ± 1.77, 141.98 ± 1.18 and 111.29 µg/g respectively. The total amino acid content was 74.90 ± 1.45%. The study revealed various secondary metabolites and major constituents of S. polycystum fibre to include fucose, mannose, galactose, xylose and rhamnose. The metabolites extracted from the seaweeds comprised n-hexadecanoic acid, 1,2-benzenedicarboxylic acid, mono(2-ethylhexyl) ester, benzenepropanoic acid, 3,5-bis(1,1-dimethylethyl)-4-hydroxy- methyl ester, 1-dodecanol, 3,7,11-trimethyl-, which were the most abundant. The physicochemical properties of S. polycystum such as water-holding and swelling capacity were comparable to several commercial fibre-rich products. In conclusion, results of this study indicate that S. polycystum is a potential candidate as functional food sources for human consumption and its cultivation needs to be encouraged.     

海藻多糖中硫酸基含量对抑制草酸钙晶体形成和修复受损伤肾小管上皮细胞的影响

采用X射线衍射法、傅里叶变换红外光谱仪、扫描电子显微镜、ζ电位仪和电感耦合等离子体发射光谱仪,比较了4种分子量相近(约3 700 Da)、但硫酸基(—OSO₃^-)含量不同的降解海藻多糖对草酸钙(CaC₂O₄)晶体生长的调控作用;采用细胞实验比较了它们对受损伤肾小管上皮细胞(HK-2)的修复能力。这4种海藻多糖分别是降解紫菜多糖(PY-1)、降解龙须菜多糖(GL-2)、降解羊栖菜多糖(SF-3)和降解裙带菜多糖(UP-4),其—OSO₃^-含量分别为17.9%、13.3%、8.2%和5.5%。结果表明,这4种多糖均能够抑制一水草酸钙(COM)生长,诱导二水草酸钙(COD)生成,增加溶液中可溶性Ca²⁺离子浓度,增加晶体表面的ζ电位绝对值,从而降低晶体的聚集程度;这些多糖均能修复被草酸氧化损伤的HK-2细胞,提高细胞活力和超氧化物歧化酶(SOD)活力,降低丙二醛(MDA)的释放量。结果表明,多糖中—OSO₃^-...     

The Potency of Seaweed Sulfated Polysaccharides for the Correction of Hemostasis Disorders in COVID-19

Hemostasis disorders play an important role in the pathogenesis, clinical manifestations, and outcome of COVID-19. First of all, the hemostasis system suffers due to a complicated and severe course of COVID-19. A significant number of COVID-19 patients develop signs of hypercoagulability, thrombocytopenia, and hyperfibrinolysis. Patients with severe COVID-19 have a tendency toward thrombotic complications in the venous and arterial systems, which is the leading cause of death in this disease. Despite the success achieved in the treatment of SARS-CoV-2, the search for new effective anticoagulants, thrombolytics, and fibrinolytics, as well as their optimal dose strategies, continues to be relevant. The wide therapeutic potential of seaweed sulfated polysaccharides (PSs), including anticoagulant, thrombolytic, and fibrinolytic activities, opens up new possibilities for their study in experimental and clinical trials. These natural compounds can be important complementary drugs for the recovery from hemostasis disorders due to their natural origin, safety, and low cost compared to synthetic drugs. In this review, the authors analyze possible pathophysiological mechanisms involved in the hemostasis disorders observed in the pathological progression of COVID-19, and also focus the attention of researchers on seaweed PSs as potential drugs aimed to correction these disorders in COVID-19 patients. Modern literature data on the anticoagulant, antithrombotic, and fibrinolytic activities of seaweed PSs are presented, depending on their structural features (content and position of sulfate groups on the main chain of PSs, molecular weight, monosaccharide composition and type of glycosidic bonds, the degree of PS chain branching, etc.). The mechanisms of PS action on the hemostasis system and the issues of oral bioavailability of PSs, important for their clinical use as oral anticoagulant and antithrombotic agents, are considered. The combination of the anticoagulant, thrombolytic, and fibrinolytic properties, along with low toxicity and relative cheapness of production, open up prospects for the clinical use of PSs as alternative sources of new anticoagulant and antithrombotic compounds. However, further investigation and clinical trials are needed to confirm their efficacy.     

Structure,conformation in aqueous solution and antimicrobial activity of ulvan extracted from green seaweed Ulva reticulata

The aim of this study is to elucidate the structure and investigate the antimicrobial activity of an ulvan obtained by water extraction from green seaweed Ulva reticulata collected at Nha Trang sea of Vietnam by using IR, NMR, SEC-MALLS and SAXS methods. The ulvan is composed of rhamnose, galactose, xylose, manose and glucose (mole ratio Rha: Gal: Xyl: Man: Glu = 1:0.12:0.1:0.06:0.03), uronic acid (22.5%) and sulphate groups (17.6%). Chemically structural determination showed that the ulvan mainly composed of disaccharide [→4)β-D-GlcA(1→4)α-L-Rha3S-(1→]. The results from SAXS indicated that ulvan under study has a rod-like bulky chain conformation. Ulvan from U. reticulata showed high antimicrobial activity, with inhibition zone diameter of 20 mm against Enterobacter cloace and 18 mm against Escherichia coli.