Molecular Modification of Polysaccharides and Resulting Bioactivities

Polysaccharides are ideal natural resources for supplements and pharmaceuticals that have received more and more attention over the years. Natural polysaccharides have been shown to have fewer side effects, but because of their inherently physicochemical properties, their bioactivities were difficult to compare with those of synthetic drugs. Thus, researchers have modified the structures and properties of natural polysaccharides based on structure–activity relationships and have obtained better functionally improved polysaccharides. This review focuses on the major modification methods of polysaccharides, and discusses the effect of molecular modification on their physicochemical properties and bioactivities. Molecular modification methods mainly include chemical, physical, and biological changes. Chemical modification is the most widely used method; it can significantly increase the water solubility and bioactivities of polysaccharides by grafting onto other groups. Physical and biological modifications only change the molecular weight of a polysaccharide, and thereby change its physicochemical properties and bioactivities. Most of the molecular modifications bring about an increase in the antioxidant activity of polysaccharides, and among these, sulfated and acetylated modifications are very common. Furthermore, phosphorylation modification is the most common application to increase antitumor activity, and modified polysaccharides have been shown to have anti‐HIV activity as the result of sulfated modification.     

天然多糖的硫酸化修饰对其生物活性影响研究进展

多糖是广泛存在于生物体内的一类生物活性大分子,因其具有多种生物活性,已引起国内外学者的高度关注。近年来研究发现,通过硫酸化修饰,可以改善多糖的生物活性,使其具有其他天然多糖无法比拟的生物活性。本文对多糖的硫酸化修饰方法及其生物活性进行综述,为今后开展硫酸化多糖的深入研究及开发应用提供参考。     

硫酸化修饰多糖抗肿瘤活性构效关系及分子机制研究进展

硫酸化修饰多糖是一类糖羟基上含有硫酸根的大分子生物活性物质,具有抗肿瘤等多种重要的生物功能活性。硫酸化多糖的抗肿瘤活性与其结构有密切联系,如取代度、分子质量和硫酸基团的取代位置等,而引起其抗肿瘤活性的分子机制也是近年来研究的热点。本文根据硫酸化修饰多糖的研究现状,对其硫酸化修饰的主要方法及抗肿瘤活性的构效关系和分子机制进行综述,并对硫酸化多糖的深入研究做出展望。     

Health effects of dietary sulfated polysaccharides from seafoods and their interaction with gut microbiota

Various dietary sulfated polysaccharides (SPs) have been isolated from seafoods, including edible seaweeds and marine animals, and their health effects such as antiobesity and anti-inflammatory activities have attracted remarkable interest. Sulfate groups have been shown to play important roles in the bioactivities of these polysaccharides. Recent in vitro and in vivo studies have suggested that the biological effects of dietary SPs are associated with the modulation of the gut microbiota. Dietary SPs could regulate the gut microbiota structure and, accordingly, affect the production of bioactive microbial metabolites. Because of their differential chemical structures, dietary SPs may specifically affect the growth of certain gut microbiota and associated metabolite production, which may contribute to variable health effects. This review summarizes the latest findings on the types and structural characteristics of SPs, the effects of different processing techniques on the structural characteristics and health effects of SPs, and the current understanding of the role of gut microbiota in the health effects of SPs. These findings might help in better understanding the mechanism of the health effects of SPs and provide a scientific basis for their application as functional food.     

Beneficial effects of sulfated polysaccharides from Sargassum wightii against mitochondrial alterations induced by Cyclosporine A in rat kidney

Sulfated polysaccharides from marine seaweeds are receiving continuous attention owing to their wide therapeutic applications and are known to inhibit free radical generation. It has been well known that mitochondria are the major sources as well as the target of free radicals. The renal tubules have high density of mitochondria and therefore show structural and functional defects in acute renal failure. Hence, the present study is designed to appraise the mitochondrial status during Cyclosporine A (CsA)-induced nephrotoxicity and the effect of sulfated polysaccharides over it. Sulfated polysaccharides (5 mg/kg body weight, subcutaneously) treatment significantly prevented the CsA-induced (25 mg/kg body weight, orally) mitochondrial damage. CsA-induced mitochondrial oxidative stress in rat kidney was evident from increased reactive oxygen species level, decreased antioxidant defense system, coupled with enhanced lipid peroxidation. Further, the activities of tricarboxylic acid cycle and electron transport chain enzymes were decreased in CsA-induced rats, along with a significant increase in the activities of urinary enzymes, thus indicating renal tubular injury. Ultrastructural changes were also in accord with the above aberrations. The above abnormalities were favorably modulated by sulfated polysaccharides supplementation, thus highlighting the significance of sulfated polysaccharides in preventing the renal mitochondrial dysfunction allied with CsA-provoked nephrotoxicity.     

多糖化学修饰的方法及其对抗肿瘤活性影响的研究进展

多糖是一种重要的生物大分子物质,具有多种生物活性。多糖的生物活性与本身的结构有着直接联系。因此,对多糖结构进行修饰,选择合适的修饰方法成为研究多糖的一个重要方向。本文主要综述了多糖的化学修饰方法及化学修饰对多糖抗肿瘤活性的影响,包括多糖的硫酸化修饰、羧甲基化修饰、酸化修饰、乙酰修饰等,并对多糖结构修饰的应用前景进行展望,以期为多糖化学修饰的深入研究与探索及糖类产品的开发与利用提供参考。     

化学修饰多糖的方法及生物活性研究进展

多糖属于生物大分子,其生物活性取决于结构及理化性质。研究表明,多糖的化学修饰可以使其结构多样性显著增加,提高生物活性,甚至增加新的生物活性。本文系统综述了近年来化学修饰多糖的研究进展,包括常用的化学修饰方法、各类化学修饰对多糖分子量、理化特性或空间结构的影响、化学修饰多糖的生物活性以及化学修饰多糖在医药和食品工业中的应用前景及挑战,以期为化学修饰多糖的深入研究提供参考建议,同时为未来基于人类健康的食品医药开发提供重要的依据。     

海藻硫酸多糖的制备及其抗凝血活性的研究进展

海藻硫酸多糖是从海藻中提取的一类生物活性多糖,迄今已提取出多种具有抗凝血活性的海藻硫酸多糖,它作为一种有望替代肝素的新型抗凝血活性物质日益受到关注。现就目前国内外对海藻硫酸多糖的制备及其抗凝活性的研究进展作一综述。     

多糖结构修饰研究进展

研究发现并非所有的多糖都具有活性或只具有较弱的活性,其受多糖分子中化学结构的影响。因此,采取有效方法对多糖进行结构修饰是增强其生物活性和促进生物活性呈现的有效途径,其对多糖构效关系的研究及多糖产品的开发和利用具有重要的实践指导意义。目前,已掌握的结构修饰方法主要有化学修饰法、物理修饰法及生物修饰法。本文主要以这三大修饰方法为主线,从各自具体的修饰方法、原理及对多糖生物活性的影响等方面对近年来国内外多糖结构修饰的研究进行综述,其中重点介绍化学修饰的具体方法及对多糖生物活性的影响,为多糖结构修饰的深入研究与探索及糖类产品的开发与利用提供合理有价值的参考。     

Application of nonthermal processing technologies in extracting and modifying polysaccharides: A critical review

Polysaccharides are natural polymer compounds widely distributed in plants, animals, and microorganisms, most of which have a broad spectrum of biological activities to promote human health. They could also be used as texture modifiers in food industry due to their excellent rheological and mechanical properties. Many researchers have shown that nonthermal processing technologies have numerous advantages, such as high extraction efficiency, short extraction time, and environmental friendliness, in the extraction of polysaccharides compared with the traditional extraction methods. Moreover, nonthermal technologies could effectively change the physicochemical properties and structural characteristics of polysaccharides to improve their biological activities or processing properties. Therefore, a comprehensive summary about the extraction and modification of polysaccharides by nonthermal technologies, including ultrasound, high hydrostatic pressure, pulsed electric fields, and cold plasma, was provided in this review. In particular, the underlying mechanisms, processing operations, and current application status of these technologies were discussed. In addition, the applications of combining nonthermal techniques with other technological methods in polysaccharide extraction and modification were briefly introduced.     

酶在植物多糖研究中的应用进展

植物多糖是植物生命活动所必需的生物大分子,其研究主要集中在提取分离、结构修饰、结构解析及生物活性等方面。酶作为常见的生物催化剂,因其高效、专一的特性,在植物多糖研究中的应用也越来越广泛。该文概述植物中淀粉、纤维素、果胶、半纤维素等多糖的结构信息,并介绍淀粉酶、纤维素酶、果胶酶、半纤维素酶等的分类和作用方式;总结酶在植物多糖提取、结构修饰及在结构分析中的应用研究进展,以期深化对酶、植物多糖的理解以及开发多糖在食品、生物医药和其他领域的应用。     

天然多糖提取、纯化及生物活性研究进展

大量研究已经证实天然多糖具有抗氧化、抗衰老、抗肿瘤、降血糖和调节肠道菌群等功效,天然多糖在生物医药、食品和保健品等领域具有较好的开发潜力和应用前景,其提取、分离纯化、理化特性和生物活性受到国内外学者的广泛关注。但不同的原料、提取和纯化方法,导致天然多糖的结构和生物活性存在差异。本文系统综述了天然多糖最新的提取和分离纯化方法以及热点的生物活性,以期为天然多糖作为功能性食品及有效的治疗药物提供重要的参考,同时为未来基于人类健康的食品开发提供重要的依据。     

Ultrafiltration isolation,physicochemical characterization,and antidiabetic activities analysis of polysaccharides from green tea,oolong tea,and black tea

Both fermentation degree and preparation method of polysaccharides could influence the bioactivity of tea polysaccharides. The aim of this study was to compare the physicochemical characterization and biological activities of the polysaccharides isolated by ultrafiltration method from three kinds of tea (green tea, oolong tea, and black tea). The bioactivities of tea polysaccharide fractions were compared from four aspects, including antioxidant activities, antiglycation activities, α-glucosidase inhibitory capability, and hypoglycemic effects on L6 myotubes. Results showed that six polysaccharides (GTPS1, GTPS2, OTPS1, OTPS2, BTPS1, and BTPS2) had different contents of neutral sugar and uronic acid, and they showed different morphologies. Six polysaccharides were composed of the seven monosaccharides with different molar ratios. BTPS1 exhibited the highest DPPH scavenging activity and hydroxyl radical scavenging activity (P < 0.05), and BTPS1 also showed the strongest antiglycation inhibitory effects (P < 0.05). BTPS1 and BTPS2 showed strong inhibitory capacity on α-glucosidase and hypoglycemic effects in L6 skeletal muscle cells. The result suggested that the degree of fermentation of tea could improve their bioactivities (BTPS > OTPS >GTPS), and TPS1 with smaller molecular weight distribution showed higher bioactivities than TPS2. This study can provide a scientific foundation for the application of tea polysaccharides and related functional products.     

Bioactive polysaccharides and oligosaccharides from garlic (Allium sativum L.): Production,physicochemical and biological properties,and structure–function relationships

Garlic is a common food, and many of its biological functions are attributed to its components including functional carbohydrates. Garlic polysaccharides and oligosaccharides as main components are understudied but have future value due to the growing demand for bioactive polysaccharides/oligosaccharides from natural sources. Garlic polysaccharides have molecular weights of 1 × 10³ to 2 × 10⁶ Da, containing small amounts of pectins and fructooligosaccharides and large amounts of inulin-type fructans ((2→1)-linked β-d -Fruf backbones alone or with attached (2→6)-linked β-d -Fruf branched chains). This article provides a detailed review of research progress and identifies knowledge gaps in extraction, production, composition, molecular characteristics, structural features, physicochemical properties, bioactivities, and structure–function relationships of garlic polysaccharides/oligosaccharides. Whether the extraction processes, synthesis approaches, and modification methods established for other non-garlic polysaccharides are also effective for garlic polysaccharides/oligosaccharides (to preserve their desired molecular structures and bioactivities) requires verification. The metabolic processes of ingested garlic polysaccharides/oligosaccharides (as food ingredients/dietary supplements), their modes of action in healthy humans or populations with chronic conditions, and molecular/chain organization–bioactivity relationships remain unclear. Future research directions related to garlic polysaccharides/oligosaccharides are discussed.     

Effect of the degree of sulfation on the physicochemical and biological properties of Pleurotus eryngii polysaccharides

Polysaccharides extracted from Pleurotus eryngii were chemically modified by sulfation and the effects on the structural and biological properties of the polysaccharides were investigated as a function of the degree of sulfation. ¹³C NMR spectroscopy demonstrated that polysaccharides from P. eryngii were mainly composed of β-(1 → 3)-glucans with β-(1 → 6) branches. The structure of the sulfated polysaccharides was confirmed by FT-IR and their degree of substitution (DS) was determined to be 0.12–0.92. When P. eryngii polysaccharides were sulfated they were shown to be effective in inhibiting cancer cell growth in a dose-dependent way. Furthermore, their DPPH radical quenching effects were improved with increasing degree of sulfation. Thus, it seemed that the chemical modification of P. eryngii polysaccharides by sulfation effectively enhanced their potential biological properties.     

海藻多糖的提取、分离纯化与应用研究进展

海藻多糖是海藻中的重要活性物质,含量较高。大量研究表明,海藻多糖具有良好的凝胶性、稳定性、成膜性,同时具有抗病毒、抗凝血、抗肿瘤、免疫调节、抗氧化等多种生物活性,被广泛应用于食品、保健医药及化妆品等方面。本文综述了海藻多糖的提取、分离纯化以及应用的研究新进展,比较分析了不同的提取及分离纯化方法的优缺点,列举了海藻多糖在食品、保健医疗及化妆品等方面的应用,指出了海藻多糖发展中存在的一些问题,并对海藻多糖未来的发展及应用进行了展望,以期能更好的开发利用海藻多糖,促进海藻多糖行业的持续健康发展。     

壶瓶碎米荠多糖硫酸化结构修饰及抗氧化活性研究

为探索壶瓶碎米荠多糖结构修饰以及修饰后多糖的生物活性变化规律,利用三氧化硫-吡啶法对壶瓶碎米荠多糖进行了硫酸化结构修饰,得到了五种不同取代度的硫酸化壶瓶碎米荠多糖,取代度分别为0.46、0.55、0.69、0.72、0.80。通过傅立叶变红外光谱初步对其改性效果进行了分析,在此基础上研究了改性壶瓶碎米荠多糖的抗氧化活性。结果显示：硫酸化改性壶瓶碎米荠多糖可以改善壶瓶碎米荠多糖的抗氧化活性,其中取代度为0.80的硫酸化壶瓶碎米荠多糖在ABTS自由基、羟自由基、DPPH自由基上具有较好的清除能力。该研究结果为壶瓶碎米荠多糖的结构以及活性研究提供了一定的试验基础。     

黄精多糖提取、分离纯化及生物活性研究进展

黄精属于百合科黄精属的草本植物，具有补气养阴，健脾，润肺，益肾等功效。多糖是黄精主要的活性成分之一，且含量丰富。黄精多糖作为一种药食两用的天然产物资源，其复杂的结构和丰富的生物活性成为食品、医药等领域开发和研究的热点之一。本文主要从黄精多糖的提取、分离纯化、结构分析、生物活性等方面的研究进行综述，并对黄精多糖的研究方向与应用前景进行展望，以期为进一步开发利用黄精多糖提供理论参考。     

Nutraceutical Potential of Seaweed Polysaccharides: Structure,Bioactivity, Safety,and Toxicity

In recent years, marine organisms including seaweeds have been highlighted as potential sources of useful metabolites and bioactive compounds, with vast biological and physiological activities. Seaweeds have long been used as a food source, for medicinal purposes, and as dietary supplements in various Asian countries, and their potential benefits have recently attracted the attention of many Western and European countries. Their commercial value depends on their applications in the food, nutraceutical, and pharmaceutical industries. Seaweeds are considered a potential source of nutraceuticals or functional foods, and analysis of taste‐oriented motives has revealed that seaweeds are preferentially selected over other types of marine foods by seafood consumers and people with high levels of health, education, and living status. It is a general perception that health conscious people prefer environmentally friendly food sources, and present an opportunity to focus on seaweed‐based foods, which have significant nutritional benefits to humans. Among the various bioactive constituents, seaweed polysaccharides have been proven to possess various beneficial properties including anticoagulant, anti‐inflammatory, antioxidant, anticarcinogenic, and antiviral activities. The diversity and composition of seaweed polysaccharides play vital roles in these biological activities. Seaweeds are a rich source of sulfated polysaccharides, which are responsible for much of the bioactivity, as they can interact with various textures and cellular proteins. A number of toxicological assays and clinical trials suggest that the ingestion of seaweeds as functional foods should be considered worldwide to improve immune responses. In this review, different polysaccharides from seaweeds and their compositions and potential nutraceutical applications are discussed.     

多糖的修饰及其改善乳化性能的研究进展

天然多糖因其结构稳定、分子量高、具有多种生物活性、安全性高等优点而表现出良好的乳化和增稠作用,被作为乳化剂广泛应用于食品工业。然而,多糖的高亲水性、难溶解性等特点导致其在高温、高盐等条件下乳化性能较差,限制了其广泛应用。通过对多糖进行修饰可以改变其分子量、结构、疏水性等功能特性,提升其乳化性能。本文综述了物理、化学和生物等修饰方法对多糖分子结构、乳化性能等的影响及修饰多糖在乳状液中应用的研究现状和进展,分析了目前修饰方法中存在的问题,并对未来发展趋势进行了展望,旨在为改善多糖乳化性能的进一步研究和拓宽其应用领域提供理论依据。