Bioactivities, isolation and purification methods of polysaccharides from natural products: A review

Polysaccharides, with an extensive distribution in natural products, represent a group of natural bioactive substances having widespread applications in health-care food products and as biomaterials. Devising an efficient system for the separation and purification of polysaccharides from natural sources, hence, is of utmost importance in the widespread applicability and feasibility of research for the development of polysaccharide-based products. High-speed counter-current chromatography (HSCCC) is a continuous liquid-liquid partitioning chromatography with the ability to support a high loading amount and crude material treatment. Due to its flexible two-phase solvent system, HSCCC has been successfully used in the separation of many natural products. Based on HSCCC unique advantages over general column chromatography and its enhanced superiority in this regard when coupled to aqueous two-phase system (ATPS), this review summarizes the separation and purification of various bioactive polysaccharides through HSCCC and its coupling to ATPS as an aid in future research in this direction.

Progresses in the study of polysaccharide from medicinal plants of the Asclepiadaceae family

In view of the recent emphasis on non-conventional chemistry, application of ultrasound in isolation of plant polysaccharides represents a viable alternative to traditional extraction processes. This review presents an extensive literature survey of ultrasound-assisted extraction of polysaccharides from different plant materials, particularly herbal plants and secondary agricultural plant sources. Targeted, multistep methods were applied with respect to differences in the types of polysaccharides and their location in plant cell walls. The effectiveness of the methods was evaluated according to yield and properties of the isolated polysaccharides in comparison to classical extraction methods. Substantial shortening of extraction time, reduction of reagent consumption and/or extraction temperature are the most important advantages of the ultrasonic treatment. In combination with sequential extraction steps using different solvents, sonication was shown to be effective in separation and/or purification of polysaccharides. The disadvantages of the sonication treatment, such as degradation and compositional changes of the polysaccharide preparations are discussed as well.

Extraction, purification, structural characterization, and biological activity of polysaccharides from Dendrobium huoshanense: A review.

SummaryAn effective method for preparative extraction and purification of the polysaccharides from mulberry leaves was studied. Orthogonal experiment was carried out to get the optimal conditions (T = 70 °C, pH = 6, t = 60 min, D = 0.4 g g−1 material) of activated carbon decolorisation. The staged, isocratic and multiple ethanol precipitation procedures were also investigated. Through the activated carbon decolorisation and 20% ethanol precipitation procedure, the polysaccharides yield reached 2.91%, and the content of neutral sugar and uronic acid were improved to 21.87% and 57.43% respectively. This process was superior to the macroporous resin adsorption and gel permeation chromatography (GPC) methods. The structure analysis indicated that the purified mulberry leaves polysaccharide (MLP) was composed of Man, GalA and Rha in the ratio of 1.0:7.2:20.0. The molecular weight measured using GPC was approximately 557 062 D. The IR and 1H NMR spectra indicated that the MLP was mainly pectin, which was classified as high‐methoxyl pectin.

Study on the purification of polysaccharides from Nostoc flagelliforme with radial flow chromatography

The isolation and purification of polysaccharide from Noscoc flagelliforme by radial flow chromatography were studied. The column (7.7 cm of bed length and 229.6 cm3 of bed volume) was packed with DEAE-01 anion ion-exchange resin and gradient eluted with NaCl solutions. The content of the polysaccharide was determined with the phenol-sulfuric acid method. The effects of sampling weight, elution velocity, and elution concentration gradient on the separation efficiency were examined and three isolated peaks were obtained. The optimal separation conditions are 10 mg of the sampling weight (sampling volume is 20 mL), 1.0 mL/min of the elution velocity, and 1.00 mol/L2 of NaCl gradient elution. The adjacent peak resolutions among the three main components (1, 2, and 3 according to their elution order) are 0.660 (R 12) and 0.786 (R 23), respectively. It is deduced that 39.8 cm of the bed length is required for the fully separation of the three polysaccharides.

Bupleurum marginatum Wall.ex DC [Apiaceae] (BM)is widely grown in southwestern China, and the whole plant is used as Traditional Chinese Medicine (TCM). Polysaccharides are main natural products in lots of TCM and have been studied for their effects of reducing oxidative stress, anti-inflammation and immune regulation. Herein, we investigated the extraction techniques of Bupleurum marginatum Wall.ex DC polysaccharides (BMP), the identification of their key components, and their ability to inhibit liver fibrosis in both cellular and animal models. Component identification indicated that monosaccharides in BMP mainly consisted of glucose, galactose, mannose, rhamnose, arabinose, and xylose. In vivo analysis revealed that BMP provided significant protective effects on N-Nitroso dimethylamine (NDMA)-induced liver fibrosis rats through reducing hepatomegaly, reducing tissue inflammation, and reducing collagen deposition. BMP also improved the hepatobiliary system and liver metabolism in accord to reduce the serum levels of ALT, AST, ALP, r-GT, and TBIL. In addition, BMP could reduce the level of inflammation and fibrosis through inhibition of IL-1β and TGF-β1. Cellular studies showed that the BMP could provide therapeutic effects on lipopolysaccharide (LPS)-induced cellular fibrosis model, and could reduce the level of inflammation and fibrosis by decreasing the level of TGF-β1, IL-1β, and TNF-α. Our study demonstrated that BMP may provide a new therapy strategy of liver injury and liver fibrosis.

Separation of polysaccharides from Lycium barbarum L. by high-speed countercurrent chromatography with aqueous two-phase system

In the present work, three hydrophilic ionic liquids based on the combination between imidazolium cations attached with ethylene glycol polymers of various lengths and hexafluorophosphate anion were designed and synthesized for the separation of polysaccharides. By employing dextran 100kDa as model compound, the effects of ionic liquid content, solvent/anti-solvent volume, and temperature on its recovery efficiency were investigated systematically. The ability of these ionic liquids to precipitate dextran 100kDa, increases with the elongation of ethylene glycol polymer chain. The established ionic liquid-based precipitation system was successfully applied to selectively precipitate polysaccharides from water extracts of three traditional Chinese medicines and the precipitation could be achieved in about 15min. In addition, the different precipitation responses of acidic, neutral, and basic polysaccharides in the ionic liquid-based precipitation system and theoretical calculations both suggested that the selective precipitation of polysaccharides was probably mediated by interaction between ionic liquids and polysaccharides. The proposed strategy facilitated the isolation and purification of polysaccharides and may trigger a novel application of ionic liquids in carbohydrate research.

Natural polysaccharides derived from plants have demonstrated significant antidiabetic properties by effectively alleviating hyperglycemia, improving insulin resistance, and preventing diabetes-associated complications. In this study, polysaccharides were extracted from Centella asiatica (L.) leaves via hot water extraction, followed by 50% (v/v) alcohol precipitation and Sevag deproteinization. Using DEAE-52 cellulose chromatography, the crude Centella asiatica polysaccharide (CAP) was separated into three fractions: P50-1, P50-2, and P50-3. P50-2 showed the greatest inhibition of α-amylase and α-glucosidase. Consequently, P50-2 was further purified using Sephacryl S-400 high-resolution (HR) gel chromatography to yield a single fraction, designated P50-2 A. An evaluation of the composition demonstrated that the compound P50-2 A, characterized as an acidic heteropolysaccharide, possesses a molecular mass of 3014 kDa. Its structure comprises fucose, rhamnose, mannose, arabinose, galactose, glucose, glucuronic acid, and galacturonic acid, arranged in a molar proportion of 0.83:1.21:6.32:24.36:37.16:19.29:5.48:5.35. Fourier transform infrared spectroscopy (FT-IR) and methylation analysis confirmed that P50-2 A is an arabinogalactan with a pyranose ring structure and 14 methylated sugar residues. Scanning electron microscopy (SEM) revealed an irregular, spongy morphology, while X-ray diffraction (XRD) analysis indicated a semi-crystalline structure comprising both amorphous and crystalline phases. In conclusion, this investigation offers the first thorough structural characterisation of CAP, providing a strong basis for further research into the links between its structure and activity as well as its uses in a variety of domains.

Branched polysaccharides have been isolated from basidiomycete raw materials of locally growing and cultivated Ganoderma lucidum. It has been found that the isolated fractions contain branched polysaccharides in the form of complexes with melanin. After purification of polysaccharides by ion exchange chromatography from locally growing and cultivated basidial raw materials, two fractions have been obtained: neutral polysaccharides of locally growing Ganoderma lucidum (GW-1), cultivated Ganoderma lucidum (GWL-1) with a yield of 25.71 and 29.85%, respectively, and anionic polysaccharides of locally growing Ganoderma lucidum (GW-2), cultivated Ganoderma lucidum (GWL-2), with a yield of 5.26 and 4.19%. The physicochemical properties of the obtained samples have been studied by IR and UV spectroscopies. The purity degree of fractions of branched polysaccharides has been determined. Using gas chromatography, one-dimensional (13C NMR, 1H NMR), and two-dimensional (COSY, TOCSY, HSQC, HMBC, NOESY) NMR spectroscopies, the compositions and molecular structures of the obtained polysaccharide samples have been determined. The results showed that the isolated and purified polysaccharides are β-glucan-type branched polysaccharides that have branch point (1,4,6)- and (1,3,6)-linked glucopyranose residues.

Marine algae have been utilized by man since prehistoric times as food, drugs or raw materials for chemicals; however, their more concentrated exploitation dates back only to the past 50 years or so. The discovery, isolation and purification of polysaccharides in the brown and red algae with characteristics favorable for different industrial applications created such a demand for these plants that worldwide shortage resulted, causing a keen competition among nations for the control of natural growing beds. Calculations are presented on the total potential world supply of harvestable algae and alternative solutions for satisfying the growing demands of the phycocolloid industries are discussed, including the current efforts to grow algae under controlled conditions for predictable harvests. The feasibility of such aquaculture ventures is evaluated and the pros and cons of creating algae factories are pointed out. TEXT Marine algae are lower plants restricted to the salt water environment. They range in size from the microscopic unicellular organisms to the largest plants on the earth. Certain groups of them reach considerable dimensions and are called kelps in general. According to their pigmentation, one Distinguishes among green, brown and red algae. All three groups are quite distinct and were already recognized by the Romans. Different uses date back to early historic times, both as food and medicaments. The brown algae were found to accumulate large quantities of iodine in their bodies, and dried weeds were already used in ancient China for the treatment of goiter. Some green algae are still cooked especially by Oriental people - into soups or made into salads) while red algae are smoked and sold as a delicacy in many of the Nordic countries. These uses of algae, however, did not warrant their large-scale exploitation. Only the discovery in this century that both the brown and red algae contain substances which are relatively easy to extract and have characteristics useful in different applications, lead to the foundation of what might be termed seaweed industry. Most of the marine algae have a highly slippery consistency, which is due to mucous substances which they manufacture in their cells and secrete toward the environment. These substances serve the protection of the plants and all have one common characteristic -- they are made up of long polymers of different sugars. Since they will produce a colloidal system in water, they fall into the category of hydrocolloids and since. They are obtained from algae) the Greek name of which is Phykos, they are termed phycocolloids. In modern industry there are basically three such colloids which are Widely utilized: [1] algin, or alginic acid) and its different salts obtained exclusively from brown algae; [2] agar-agar, produced by certain red algae and [3] carrageen in, extracted from other red algae. Alginates are widely utilized in different foods for the high viscosity solutions they produce where such requirement is present, as in creams, to which they impart a better whipping ability.

Polysaccharides from litchi (Litchi chinensis) seeds were isolated and purified using ion exchange column chromatography. Molecular weight distribution of polysaccharides and monosaccharides were detected. Preliminary structural characterisation of polysaccharides was conducted using infrared, nuclear magnetic, and other spectroscopy techniques in combination with methylation analysis. In vitro cell culture experiments were designed to detect the effects of polysaccharides on cell growth and cellular glucose consumption. We extracted and analysed three polysaccharides from litchi seed. Monosaccharide composition and infrared spectroscopy detection showed that the skeleton structure of polysaccharides consisted of glucose and mannose. Polysaccharides 1 and 2 are similar and have relatively high glucose content (around 70%); polysaccharide 3 has 39.17% glucose only but is rich in arabinose (about 21.03%). In a certain range of use (50~1000 μg ml–1), polysaccharides 1 and 2 have no significant impacts on cell growth, while polysaccharide 3 can promote proliferation to some extent. All three polysaccharides can promote in vitro cellular glucose consumption, especially polysaccharide 3, which shows the strongest promotion, a significant dose effect, and synergistic effect with insulin. The above results highlight important roles of litchi seed polysaccharides in promoting cell growth and validate litchi seed polysaccharides as potential drugs for hypoglycaemia.

Isolation and Purification of Polysaccharides from Cordyceps minlitaris and Its Inhibition on the Proliferation of Rat Glomerular Mesangial Cells