Extraction, purification, structural modification, activities and application of polysaccharides from different parts of mulberry.

The mulberry plant is a member of the Moraceae family and belongs to the Morus genus. Its entire body is a treasure, with mulberries, mulberry leaves, and mulberry branches all suitable for medicinal use. The main active ingredient in mulberries is mulberry polysaccharide. Studies have shown that polysaccharides from different parts of mulberry exhibit antioxidant, antidiabetic, antibacterial, anti-inflammatory, and blood pressure-lowering properties. There are more studies on the biological activities, extraction methods, and structural characterization of polysaccharides from different parts of mulberry. However, the structural characterization of mulberry polysaccharides is mostly confined to the types and proportions of monosaccharides and the molecular weights of polysaccharides, and there are fewer systematic studies on polysaccharides from different parts of mulberry. In order to better understand the bioactive structure of mulberry polysaccharides, this article discusses the recent research progress in the extraction, separation, purification, bioactivity, structural modification, and application of polysaccharides from different parts of mulberry (mulberry leaves, mulberry fruits, and mulberry branches). It also delves into the pharmacological mechanisms of action of mulberry polysaccharides to provide a theoretical basis for further research on mulberry polysaccharides with a view to their deeper application in the fields of feed and nutraceuticals.

Preparation and analysis of polysaccharide from Solanum tuberdsm.

The crude Solanum tuberdsm polysaccharides (STP) were extracted with hot water. In the process of extraction, proteins, pigments, small molecules and salts in the mixture were removed by Sevage reagent, diatomite and distilled water dialysis, respectively. In addition, the process conditions of protein removal by response surface methodology (RSM) were optimized, and the optimum process conditions of Sevage method were established as follows: ultrasound power 350 W, ultrasound time 20 min, deproteinization twice, volume ratio of polysaccharide solution to Sevage reagent 1:1 (mL/mL). Under these conditions, the protein removal rate was 93.14%.

Preparation and Antioxidant Activity of Acetylated Mung Bean Peel Polysaccharides.

Mung bean peel polysaccharides are one of the main active components in mung bean peel. Acetylated mung bean peel polysaccharides were prepared by extracting and acetylating them, and characterized by infrared and ultraviolet methods to preliminarily understand the structural characteristics and activity of acetylated mung bean peel polysaccharides. Acetylation modification can improve the structure of polysaccharides, thereby causing changes in their properties. The product obtained after acetylation modification exhibited new characteristic absorption peaks at 1732 cm-1 , and the scavenging ability of hydroxyl radicals was improved. Therefore, acetylation modification of mung bean peel polysaccharides could enhance the activity by improving the structure, which provided an experimental basis for the application of mung bean peel polysaccharides.

Preparation and Analysis of Pueraria lobata Polysaccharides.

Pueraria lobata polysaccharides (PLPs) were obtained by a hot water extraction method. Starting from the single factor experiment, the extraction was optimized by response surface methodology, and the following optimal extraction parameters were obtained: the extraction temperature was 84 °C, the liquid-solid ratio was 11 mL/g, the extraction time was 73 min, and the extraction rate of polysaccharides was 8.59%. The Sevag method was used to remove the protein soluble in water and H2O2 was used to remove the pigment; then PLPs were precipitated with three times of anhydrous ethanol, soluble salts and other small molecules were removed by dialysis, and finally refined PLPs were obtained by freeze-drying.

Preparation, Structural Analysis and Antioxidant Activity of Polysaccharides and Their Derivatives from Pueraria lobata.

Pueraria lobata polysaccharides (PLPs) were obtained by hot water extraction using Pueraria lobata as raw material. Structural analysis revealed that PLPs may have a repetitive backbone units of →4) -α-D-Glcp (1→4-α-D-Glcp (1→. Phosphorylated Pueraria lobata polysaccharides (P-PLPs), carboxymethylated Pueraria lobata polysaccharides (CM-PLPs) and acetylated Pueraria lobata polysaccharides (Ac-PLPs) were obtained by chemical modifications of PLPs, respectively. The physicochemical properties and antioxidant activities of these four Pueraria lobata polysaccharides were studied in comparison. In particular, the clearance rate of P-PLPs exceeded 80 %, and was expected to achieve the same effect as Vc . The results showed that the effects of different chemical modifications on the antioxidant activity of PLPs varied greatly.

Extraction, structure, and activity of polysaccharide from Radix astragali.

Radix astragali polysaccharide (RAP) is a water-soluble heteropolysaccharide. It is an immune promoter and regulator, and has antivirus, antitumor, anti-aging, anti-radiation, anti-stress, anti-oxidation and other activitys. The extraction, separation, purification, structure, activity and modification of RAP were summarized. Some extraction methods of RAP had been introduced, and the separation and purification methods of RAP were reviewed, and the structure and activity of RAP were highly discussed. Current derivatization of RAP was outlined. Through the above discussion that the yield of crude polysaccharides from Radix astragali by enzyme-assisted extraction was significantly higher than that by other extraction methods, but each extraction method had different extraction effects under certain conditions, and the activity efficiency of RAP was also different. Therefore, it is particularly important to optimize the extraction method with known better yield for the study of RAP. In addition, the purification and separation of RAP are the key factors affecting the yield and activity of RAP. At the same time, there are still few studies on the derivatiration of Radix astragali polysaccharide, but the researches in this area are very important. RAP also has many important pharmacological effects on human body, but its practical application needs further study. Finally, studies on the structure-activity relationship of RAP still need to be carried out by many scholars. This review would provide some help for further researches on various important applications of RAP.

Extraction, derivatization and antioxidant activities of onion polysaccharide.

The preparation of purified polysaccharides was described from fresh onions by hot water extraction, protein removal and dialysis treatment. The structure of onion polysaccharide was confirmed by 13C NMR, DEPT, COSY, HSQC and HMBC. In order to study the structure-activity relationship of onion polysaccharide, the derivatives of onion polysaccharide including acetylated onion polysaccharide and phosphoric onion polysaccharide were prepared. On this basis, the antioxidant activities of onion polysaccharide and its derivatives were tested in vitro. The results showed that onion polysaccharides and its derivatives had a good antioxidant activity, and the activity of phosphorylated polysaccharide was similar to that of Vc positive control.

Extraction, derivatization, and antioxidant activity of Morinda citrifolia polysaccharide.

The polysaccharide from Morinda citrifolia fermentation liquor was extracted by the hot water method. The acetylated polysaccharide, phosphorylated polysaccharide, carboxymethylated polysaccharide, and sulfated polysaccharide were identified by IR and NMR spectra. The results showed that Morinda citrifolia polysaccharide and its derivatives showed the good antioxidant activity, and them up to Vc level. These results provide a good basis for studying the antioxidant activity and structural-activity relationship of Morinda citrifolia polysaccharide and its derivatives.

Extraction and deproteinization process of polysaccharide from purple sweet potato.

Extraction and deproteinization process of polysaccharide from purple sweet potato (PPSP) were optimized via the response surface methodology (RSM). The results indicated that the optimal conditions of extraction in hot water of PPSP were as follows: The extraction temperature was 120℃, the extraction time was 2.5 hr, and the solid-liquid ratio was 1∶10 (g/ml). The optimal conditions of Sevage deproteinization were as under the oscillation time was 20 min, the deproteinization times was twice, and polysaccharide solution-Sevage reagent ratio was 1:1 (ml/ml). The extraction yield of PPSP was 3.32%, and the protein removal rate was 93.14% in such a condition.

Preparation, structure, and properties of tea polysaccharide.

Tea polysaccharide is a kind of acid glycoprotein complex extracted from tea. Tea polysaccharide has a variety of biological activities, especially the hypoglycemic effect is outstanding. It is good for human health. Tea polysaccharides have been extensively studied over the past few decades. The advantages and disadvantages of water extraction, enzyme-assisted extraction, ultrasonic-assisted extraction, microwave-assisted extraction, and supercritical fluid extraction were described. At the same time, the structure and biological activity of tea polysaccharide were also summarized. The development of tea polysaccharide was prospected.

Preparation and antioxidant activity of phosphorylated polysaccharide from purple sweet potato.

Purple sweet potato polysaccharide was extracted via hot water, and it was chemically modified by phosphorus oxychloride-pyridine to obtain phosphorylated polysaccharide from purple sweet potato (P-PPSP) with certain degrees of substitution. Furthermore, the structure and antioxidant activity in vitro of PPSP and phosphorylated derivative were compared. The result indicated that the phosphorylation modification product of polysaccharide from purple sweet potato could improve the scavenging effect on hydroxyl radical and superoxide anion of PPSP, significantly. It also could improve the anti-lipid peroxidation ability while fail to improve the reducing ability of PPSP.

Extraction, structural analysis, and activities of rice bran polysaccharide.

The rice bran polysaccharide was extracted from defatted rice bran, and the optimal conditions of the experiment were determined. The chemical structure of rice bran polysaccharide was analyzed by IR and 13 C NMR. Three rice bran polysaccharide derivatives were prepared and characterized, namely carboxymethylated rice bran polysaccharide, phosphorylated rice bran polysaccharide, and acetylated rice bran polysaccharide. It showed that the phosphorylated rice bran polysaccharide had good activity.

The structure-activity relationships of natural glucans.

In recent years, glucan has become one of the hotspots in life science research. It is widely concerned because of its advantages, such as good immune regulation, antitumor, antivirus, hypoglycemic and lipid-lowering effects, antioxidation, antiaging, low toxicity, and high efficiency. At present, there are still two problems in the pharmacodynamics of glucans. Firstly, compared with other drugs used in clinic, most of the glucans still lack information about the mechanism of action between glucans and corresponding ligands in vivo. Secondly, the research on the structure-activity relationship of glucans is still slow. Herein, the structure-activity relationships of glucans were reviewed. The relationship between structure and biological activity is very important for the development of new glucan drugs.

Antioxidant activities and mechanisms of polysaccharides.

Polysaccharide, as one of the effective components of traditional Chinese medicine, has the activities of anti-oxidation, anti-virus, improving immunity and so on. Chinese herbal polysaccharides have a wide range of sources. It is found that polysaccharides in many plants and microorganisms have significant antioxidant effects, mainly through the endogenous antioxidant stress Nrf2/ARE pathway to regulate the expression of downstream antioxidant enzymes. These antioxidant enzymes can further block the free radical chain reaction, thus reducing the generation of free radicals. Secondly, by inhibiting the expression of iNOS mRNA and reducing NO production, it can significantly increase the antioxidant capacity and reduce oxidative stress injury. Polysaccharides are rich in natural resources, their multi-channel, multi-target, multi-effect, and other characteristics have made great progress in antioxidants.

Chemical composition analysis and antioxidant activity of black rice pigment.

The purpose of this research was conducted to determine anthocyanin constituent from the grains of Purple black rice No. 6. Moreover, the in vitro antioxidant activity of black rice pigment (BRP) was evaluated. The crude extract of black rice was isolated and purified by silica gel thin layer chromatography. Anthocyanins were elucidated using ultraviolet visible spectroscopy, infrared spectroscopy, nuclear magnetic resonance spectroscopy, and high-performance liquid chromatography. Meanwhile, salicylic acid Fenton system, superoxide radical system, H2 O2 scavenging system, DPPH-free radical scavenging system, and Prussian blue method were used to determine the free radical scavenging ability and total reducing ability of BRP. Overall results suggest that the main component of BRP is cyanidin-3-glucoside, which is a kind of anthocyanins. It also had significant scavenging capacity to OH, O2- , H2 O2 , DPPH, and its scavenging rate and reducing ability increased with the increase in pigment concentration.

Preparation, analysis, antioxidant activities in vivo of phosphorylated polysaccharide from Momordica charantia.

Momordica charantia (bitter melon) is a kind of medicine and food homologous fruit. The Momordica charantia polysaccharide has the physiological functions of clearing away heat and detoxification, lowering blood sugar, improving immunity and so on. It is an ideal health care product. The extraction of Momordica charantia polysaccharide was carried out by hot water method. The structure of the polysaccharide and its phosphorylated derivative was determined by IR and NMR, which indicated that the chemical modification was successful. The polysaccharide could significantly increase the content of SOD and CAT in serum, liver and spleen tissue of mice, and reduce the content of MDA in serum, liver and spleen tissue to a certain extent.

Modification and application of polysaccharide from traditional Chinese medicine such as Dendrobium officinale.

Polysaccharides have various biological activities, such as antioxidant, anti-tumor, antiviral, anti-aging, anti-inflammatory, anti-radiation, hypoglycemic and lipid lowering, immune regulation, etc. Although many polysaccharides have been proved to have various biological activities, in the research process, it has been found that more polysaccharides in nature do not have biological activities or have low activities, and some polysaccharides have poor activities due to lack of certain groups. While others are due to polysaccharide with too large molecular weight, because its molecular weight is too large to smoothly enter cells and thus cannot exert its activity. For the former, we need to adopt molecular grafting modification. This kind of modification method is mainly chemical modification method, which increases the functional groups and molecular weight of various polysaccharides to improve their biological activity. For the latter, we need to adopt molecular degradation modification, which includes biodegradation, physical degradation, chemical degradation and other means to improve the solubility of polysaccharide in water phase by reducing its molecular weight, thus improving its activity. This article mainly introduces polysaccharide structure modification methods that have been widely used in recent years.

The antioxidant activities in vivo of bitter gourd polysaccharide.

The antioxidant activities of polysaccharide from bitter gourd were studied. It was found that bitter gourd polysaccharide could significantly increase SOD and CAT contents in serum, liver and brain of mice, and reduce MDA levels in serum, liver and brain to a certain extent in vivo. So, bitter gourd polysaccharide should be a potential antioxidant.

The antioxidant activities of balsam pear polysaccharide.

The antioxidant activities of polysaccharide from balsam pear were studied. It was determined by gel permeation chromatography that the molecular weight distribution of purified polysaccharide was concentrated near 33582 Da. It indicated that the monosaccharide components were rhamnose, galacturonic acid, galactose, xylose and arabinose. Fourier transform infrared spectroscopy, nuclear magnetic resonance and Congo red experiments showed that there are C1, C2, C3, C5 links, and stable ß-triple helix conformation in aqueous solution. It was found that polysaccharide had good scavenging effect on free radicals. So, balsam pear polysaccharide should be a potential antioxidant.

The antioxidant activities of garlic polysaccharide and its derivatives.

Garlic was used as raw material to extract garlic polysaccharide (P) with hot water extraction method. IR and NMR spectra showed that the preparation of sulfated garlic polysaccharide (SP), phosphorylated garlic polysaccharide (PP) and carboxymethylated garlic polysaccharide (CMP) was successful. The sugar content of P, SP, PP and CMP was determined, and their degree of substitution was measured. Hydroxyl radical scavenging ability, superoxide anion scavenging ability, significant reduction capacity, and anti-lipid peroxidation ability of P, SP, PP, CMP and VC were determined. It showed that the introduction of substituents had different effects on the antioxidant activities of P.