Effects of extraction methods on immunology activity and chemical profiles of Lycium barbarum polysaccharides

Polysaccharides in fruits: Biological activities, structures, and structure-activity relationships and influencing factors-A review

Fruits are a rich source of polysaccharides, and an increasing number of studies have shown that polysaccharides from fruits have a wide range of biological functions. Here, we thoroughly review recent advances in the study of the bioactivities, structures, and structure-activity relationships of fruit polysaccharides, especially highlighting the structure-activity influencing factors such as extraction methods and chemical modifications. Different extraction methods cause differences in the primary structures of polysaccharides, which in turn lead to different polysaccharide biological activities. Differences in the degree of modification, molecular weight, substitution position, and chain conformation caused by chemical modification can all affect the biological activities of fruit polysaccharides. Furthermore, we summarize the applications of fruit polysaccharides in the fields of pharmacy and medicine, foods, cosmetics, and materials. The challenges and perspectives for fruit polysaccharide research are also discussed.

Ultrasonic-assisted extraction of a low molecular weight polysaccharide from Nostoc commune Vaucher and its structural characterization and immunomodulatory activity

In the current study, a novel crude polysaccharide (cNCEP) was extracted from N. commune Vaucher utilizing ultrasonic-assisted extraction (UAE) with 60 % ethanol, employing response surface methodology. The optimal yield of cNCEP was determined to be 8.07 ± 0.08 mg/g, achieved through ultrasonic-assisted extraction under the conditions of a material-to-liquid ratio of 1:22, temperature of 56 °C, power of 570 W, and duration of 147 min. Subsequent purification of NCEP via Sephadex G75 resulted in a novel polysaccharide with a molecular weight of 20.466 kDa. NCEP exhibited significant scavenging activites against DPPH and hydroxyl radicals, as well as notable in vitro immunomodulatory properties. Furthermore, the mechanisms underlying the immunomodulatory effects of NCEP, involving enhancement of immunity, were investigated, revealing potential regulation of MAPK and TLR4-IRF7-NF-κB signaling pathways through RNA-Seq and Western blot analyses. These findings highlight the promising potential of NCEP as an organic immunomodulatory agent and functional food ingredient.

Characterization and biological activities of polysaccharides extracted from Auricularia auricula with different extraction methods

Polysaccharides derived from Auricularia auricula exhibit diverse biological activities and hold significant potential for commercial utilization as functional food ingredients. In this investigation, polysaccharides from A. auricula were obtained using six extraction techniques (ammonium oxalate solution extraction, sodium hydroxide solution extraction, hot water extraction, pectinase and cellulase-assisted extraction, ultrasonic-assisted extraction, and microwave-assisted extraction). Subsequently, a comprehensive comparison was conducted to evaluate their physicochemical properties and biological functionalities. The ammonium oxalate solution extraction method yielded a higher extraction rate (11.76%) and polysaccharide content (84.12%), as well as a higher uronic acid content (10.13%). Although the six Auricularia polysaccharides had different molecular weight distributions, monosaccharide molar ratios, similar monosaccharide compositions, and characteristic functional groups of polysaccharides, they exhibited different surface morphology. In vitro assays showed that polysaccharides extracted by ammonium oxalate solution possessed good scavenging ability against DPPH free radical, hydroxyl free radical and superoxide anion free radical as well as reduction power of iron ion. At the same time, both polysaccharides extracted by ammonium oxalate solution and sodium hydroxide solution promoted NO production in mouse macrophages along with the secretion of cytokines TNF-α, IL-1β, and IL-6. These results indicated significant differences in the structure and characteristics among Auricularia polysaccharides prepared by various extraction methods, which may be related to the variety or origin of A. auricula; furthermore, their bioactivities varied accordingly in vitro assays where the ammonium oxalate solution extraction method was found more beneficial for obtaining high-quality bioactive Auricularia polysaccharides.

Exploration of green preparation strategy for Lycium barbarum polysaccharide targeting Bacteroides proliferative and immune-enhancing activities and its potential use in geriatric foods

Lycium barbarum polysaccharide (LBP) is beneficial for elderly people, but its use is limited in geriatric foods due to the lack of comprehensive information on its preparation strategy and physical property. In this study, the low-ester rhamnogalacturonan-I (RG-I) type pectic polysaccharide-protein complexes with varying physicochemical properties, structural characteristics, proliferative activities on Bacteroides, and immune-enhancing activities on RAW 264.7 cells, were obtained by moderate-temperature acid extraction within adjustment of enzymatic and physical pretreatments. LBP prepared by moderate-temperature acid extraction, namely S1-A, showed the strongest immune-enhancing activity via increasing the phagocytosis capacity and NO release of RAW 264.7 cells by 23 % and 76 %, respectively. S1-A exhibited relatively high viscosity and calcium ion response characteristic with the application potential for thickened liquid foods for the elderly with dysphagia. LBP prepared by composite cellulase and pectinase pretreatment combined with moderate-temperature acid extraction, namely S1-M1, showed the strongest Bacteroides proliferative activity that was equivalent to 0.60-0.97 times of that of inulin. S1-M1 exhibited extremely low viscosity and strong tolerance to food nutrients with high processing applicability for fluid foods. This study provided crucial data for the preparation and application of LBP targeting gut microbiota disorders and immunosenescence for the development of geriatric foods.

Bioactive Components of Lycium barbarum and Deep-Processing Fermentation Products

Lycium barbarum, a homology of medicine and food, contains many active ingredients including polysaccharides, polyphenol, betaine, and carotenoids, which has health benefits and economic value. The bioactive components in Lycium barbarum exhibit the effects of antioxidation, immune regulation, hypoglycemic effects, and vision improvement. Recently, the development of nutrition and health products of Lycium barbarum has been paid more and more attention with the increase in health awareness. A variety of nutrients and bioactive components in wolfberry can be retained or increased using modern fermentation technology. Through fermentation, the products have better flavor and health function, which better meet the needs of market diversification. The main products related to wolfberry fermentation include wolfberry fruit wine, wolfberry fruit vinegar, and lactic acid fermented beverage. In this review, the mainly bioactive components of Lycium barbarum and its deep-processing products of fermentation were summarized and compared. It will provide reference for the research and development of fermented and healthy products of Lycium barbarum.

Slit dual-frequency ultrasound-assisted pulping of Lycium barbarum fresh fruit to improve the dissolution of polysaccharides and in situ real-time monitoring

In this study, the slit dual-frequency ultrasound-assisted pulping of fresh Lycium barbarum fruit was optimized to improve the dissolution of polysaccharides. The microscopic mechanism of polysaccharide dissolution was explored through establishing polysaccharides dissolution kinetics model and visualizing the multi-physical fields during ultrasonic process, and an in situ real-time monitoring model was established by the relationship between the chemical value and spectral information collected by near-infrared spectroscopy. The results showed that, under optimal conditions, treatment with ultrasound (28-33 kHz, 250 W, 30 min) not only significantly promoted the dissolution rate of polysaccharides in Lycium barbarum pulp (LBPPs, increased by 43.64 %, p < 0.01), reduced its molecular weight, but also improved the arabinose molar ratio, the uniformity of polysaccharide particles, and the antioxidant activity of LBPPs. Correlation analysis indicated that ultrasonic treatment is closely related to LBPPs content, particle size and scavenging capacity against superoxide anion radicals (ptotal sugar content < 0.01, pparticle size < 0.05 and psuperoxide anion scavenging < 0.05). Moreover, the in situ real-time monitoring model for the pulping process could quantitatively predict LBPPs dissolution rate and its superoxide anion radical scavenging capacity with good calibration and prediction performance (Rc = 0.9841, RMSECV = 0.0873, Rp = 0.9772, RMSEP = 0.0530; Rc = 0.9874, RMSECV = 0.1246, Rp = 0.9868, RMSEP = 0.0665). These results indicated that slit dual-frequency ultrasound has great potential in improving the quality of Lycium barbarum pulp, which may provide theoretical support for the industrial development of intelligent systems for polysaccharides preparation.

Polysaccharides-Naturally Occurring Immune Modulators

The prevention of disease and infection requires immune systems that operate effectively. This is accomplished by the elimination of infections and abnormal cells. Immune or biological therapy treats disease by either stimulating or inhibiting the immune system, dependent upon the circumstances. In plants, animals, and microbes, polysaccharides are abundant biomacromolecules. Due to the intricacy of their structure, polysaccharides may interact with and impact the immune response; hence, they play a crucial role in the treatment of several human illnesses. There is an urgent need for the identification of natural biomolecules that may prevent infection and treat chronic disease. This article addresses some of the naturally occurring polysaccharides of known therapeutic potential that have already been identified. This article also discusses extraction methods and immunological modulatory capabilities.

Edible Quality Analysis of Different Areca Nuts: Compositions, Texture Characteristics and Flavor Release Behaviors

The areca nut is one of the most important cash crops in the tropics and has substantial economic value. However, the research information about the edible quality of different areca nuts is still insufficient. This study compared the composition, texture characteristics and flavor release behaviors of four different areca nuts (AN1, AN2, AN3 and AN4) and two commercially dried areca nuts (CAN1 and CAN2). Results showed that AN1 had higher soluble fiber and lower lignin, which was the basis of its lower hardness. Meanwhile, the total soluble solid (TSS) of AN1 was the highest, which indicated that AN1 had a moister and more succulent mouthfeel. After the drying process, the lignification degree of AN1 was the lowest. Through textural analyses, the hardness of AN1 was relatively low compared to the other dried areca nuts. AN1, CAN1 and CAN2 had higher alkaline pectin content and viscosity, and better flavor retention, which indicated better edible quality. The present study revealed the differences of various areca nuts and provided vital information to further advance the study of areca nuts.

Three acidic polysaccharides derived from sour jujube seeds protect intestinal epithelial barrier function in LPS induced Caco-2 cell inflammation model

Normal intestinal epithelial barrier function plays a key role in the prevention of many diseases such as infectious enteritis, inflammatory bowel disease, obesity, etc. In this study, three novel acidic polysaccharides ZY-2, ZY-3 and ZY-4 were isolated from sour jujube (Ziziphus jujuba Mill. var. Spinosa) seeds and purified by DEAE Sephrose Fast Flow gel. The molecular weight of ZY-2, ZY-3 and ZY-4 was 7.76 kDa, 10.71 kDa and 8.31 kDa respectively, mainly composed of different proportions of mannose, rhamnose, glucose, glucuronic acid, galacturonic acid, galactose, xylose and arabinose. ¹H NMR and Congo red experiment results showed that the three polysaccharides mainly contained both α-type and β-type glycosidic bonds with obvious triple helix structural traits. The polysaccharides could up-regulate the expression levels of occludin and ZO-1 in LPS-induced inflammation Caco-2 cells, and reduce IL-6, IL-8, IL-1β and TNF-α significantly. In conclusion, the acidic polysaccharides from sour jujube seeds exhibited great potential in protection intestinal epithelial barrier function through anti-inflammatory effects.

Isolation, structures, bioactivities, application and future prospective for polysaccharides from Tremella aurantialba: A review

Since ancient times, Tremella aurantialba has been proposed to have medicinal and food benefits. Modern phytochemistry and pharmacological studies have demonstrated that polysaccharides, the main components from T. aurantialba appear to be an all-round talent resisting a variety of chronic inflammatory diseases and protecting against different types of tumors, diabetes and cardiovascular diseases. These health and pharmacological benefits have gained much attention from scholars around the world. Further, more and more methods for polysaccharides extraction, purification, structure identification have been proposed. Significantly, the bioactivity of fungus polysaccharides is affected by many factors such as extraction and purification conditions and chemical structure. This paper provides an overview of recent advances in the isolation, structural features and biological effects of polysaccharides derived from T. aurantialba, covers recent advances in the field and outlines future research and applications of these polysaccharides.

Ginger polysaccharides relieve ulcerative colitis via maintaining intestinal barrier integrity and gut microbiota modulation

Ulcerative colitis (UC) is an autoimmune disease afflicting an increasing number of patients and increasing demands towards the development of efficacious and safe drugs. Recently, with increasing interest in alternative medicines, natural resources have become a hotspot for drug discovery against UC. In addition to being consumed as a food and spice, ginger is also widely used as a well-recognized gastrointestinal herbal medicine. With a long history in the treatment of digestive disorders, the potential of ginger in alleviating UC has been documented in several experimental models and clinical trials. However, as a major active constituent of ginger, ginger polysaccharides (GP) and its effect on UC has yet to be reported. In this study, GP was firstly separated and characterized. In a dextran sulfate sodium (DSS)-induced colitis mouse model, GP alleviated UC symptoms by inhibiting pro-inflammatory cytokines levels to regulate intestinal inflammation, repairing the intestinal barrier as indicated by occludin-1 and ZO-1, as well as regulating gut microbiota. Taking these results together, we believe GP could be an innovative option in developing functional foods or therapeutic agents for UC management.

Effects of Lycium barbarum L. Polysaccharides on Vascular Retinopathy: An Insight Review

Vascular retinopathy is a pathological change in the retina caused by ocular or systemic vascular diseases that can lead to blurred vision and the risk of blindness. Lycium barbarum polysaccharides (LBPs) are extracted from the fruit of traditional Chinese medicine, L. barbarum. They have strong biological activities, including immune regulation, antioxidation, and neuroprotection, and have been shown to improve vision in numerous studies. At present, there is no systematic literature review of LBPs on vascular retinal prevention and treatment. We review the structural characterization and extraction methods of LBPs, focus on the mechanism and pharmacokinetics of LBPs in improving vascular retinopathy, and discuss the future clinical application and lack of work. LBPs are involved in the regulation of VEGF, Rho/ROCK, PI3K/Akt/mTOR, Nrf2/HO-1, AGEs/RAGE signaling pathways, which can alleviate the occurrence and development of vascular retinal diseases in an inflammatory response, oxidative stress, apoptosis, autophagy, and neuroprotection. LBPs are mainly absorbed by the small intestine and stomach and excreted through urine and feces. Their low bioavailability in vivo has led to the development of novel dosage forms, including multicompartment delivery systems and scaffolds. Data from the literature confirm the medicinal potential of LBPs as a new direction for the prevention and complementary treatment of vascular retinopathy.

Structural characterization of polysaccharides recovered from extraction residue of ginseng root saponins and its fruit nutrition preservation performance

Polysaccharides recovered from extraction residue of ginseng root saponins, i.e., ginsenosides-extracting residue polysaccharides (GRP), were separated into two fractions, GRP-1 and GRP-2. Fourier infrared and nuclear magnetic resonance spectra, as well as high-performance liquid chromatography and gel permeation chromatography measurements, showed GRP-1 was composed of mainly starch-like glucans and GRP-2, relatively a smaller portion, was a mixture of heteropolysaccharides composed of starch-like glucans, rhamnogalacturonan-I pectin, and arabinogalactans, and they had similar molecular weights. These results proved that the structure of GRP was not destroyed and GRP still maintained strong antioxidant activities. In addition, GRP coating on surfaces of fruit slowed their deterioration and maintained their nutritional effects. Correlation and PCA analyses on various quality and antioxidant parameters supported the above findings and a possible mechanism in fruit preservation was then proposed. Knowing the structural features and bioactivities of GRP gives insights into its application. Specifically, GRP served as an environmentally friendly coating that can be used to preserve the nutrients and other quality indicators of strawberries and fresh-cut apples, paving the way for future new approaches to food preservation using polysaccharides or other natural products.

Supplementation of Lycium barbarum Polysaccharide Combined with Aerobic Exercise Ameliorates High-Fat-Induced Nonalcoholic Steatohepatitis via AMPK/PPARα/PGC-1α Pathway

Nonalcoholic steatohepatitis (NASH) is a subtype of nonalcoholic fatty liver disease (NAFLD). Either Lycium barbarum polysaccharide (LBP) or aerobic exercise (AE) has been reported to be beneficial to hepatic lipid metabolism. However, whether the combination of LBP with AE improves lipid accumulation of NASH remains unknown. Our study investigated the influence of 10 weeks of treatment of LBP, AE, and the combination (LBP plus AE) on high-fat-induced NASH in Sprague-Dawley rats. The results showed that LBP or AE reduced the severity of the NASH. LBP plus AE treatment more effectively ameliorated liver damage and lowered levels of serum lipid and inflammation. In addition, the combination can also regulate genes involved in hepatic fatty acid synthesis and oxidation. LBP plus AE activated AMPK, thereby increasing the expression of PPARα which controls hepatic fatty acid oxidation and its coactivator PGC-1α. Our study demonstrated the improvement of LBP plus AE on NASH via enhancing fatty acid oxidation (FAO) which was dependent on AMPK/PPARα/PGC-1α pathway.

Ultrasound-assisted extraction of highly nutritious date sugar from date palm (Phoenix dactylifera) fruit powder: Parametric optimization and kinetic modeling

Alternative sweeteners to white sugar with a lower calorie content and glycemic index obtained through date palm fruits is of great interest to the food industry. In this study, ultrasound-assisted extraction of nutritive sugar from date fruit powder was investigated through Box-Behnken design. A maximum total sugar content (TSC) of 812 mg glucose eq./g of DFP was obtained with a sugar extraction yield (SEY) of 81.40 ± 0.27 % under the following optimal extraction conditions: extraction temperature of 60 °C, extraction time of 30 min, and L/S ratio of 7.6 mL/g. Various modern techniques were used to characterize the obtained extracts and associated residues. The results showed that the extract contained fructose, glucose, and sucrose and had good thermal stability. Furthermore, SEM and TSC analysis revealed that ultrasonic treatment of the biomass improved mass transfer diffusion due to acoustic or ultrasonic cavitation, resulting in a higher sugar yield.

Extraction, purification, structural characterization, and gut microbiota relationship of polysaccharides: A review

Intestinal dysbiosis is one of the major causes of the occurrence of metabolic syndromes, such as obesity, diabetes, nonalcoholic fatty liver disease, and cardiovascular diseases. Polysaccharide-based microbial therapeutic strategies have excellent potential in the treatment of metabolic syndromes, but the underlying regulatory mechanisms remain elusive. Identification of the internal regulatory mechanism of the gut microbiome and the interaction mechanisms involving bacteria and the host are essential to achieve precise control of the gut microbiome and obtain valuable clinical data. Polysaccharides cannot be directly digested; the behavior in the intestinal tract is considered a "bridge" between microbiota and host communication. To provide a relatively comprehensive reference for researchers in the field, we will discuss the polysaccharide extraction and purification processes and chemical and structural characteristics, focusing on the polysaccharides in gut microbiota through the immune system, gut-liver axis, gut-brain axis, energy axis interactions, and potential applications.

Lycium Genus Polysaccharide: An Overview of its Extraction, Structures, Pharmacological Activities and Biological Applications

Polysaccharide is considered to be the main active ingredient of the genus Lycium L., which is taken from the dried fruit of the famous Chinese herbal medicine and precious tonic known as wolfberry. Traditional uses include nourishing the liver and kidney and improving eyesight, with widespread use in the clinical practice of traditional Chinese medicine. Many studies have focused on the isolation and identification of the genus Lycium L. polysaccharide and its biological activities. However, the variety of raw materials and the mechanisms of polysaccharides differ. After extraction, the structure and biological activity of the obtained polysaccharides also differ. To date, approximately 58 kinds of polysaccharides have been isolated and purified from the Lycium genus, including water-soluble polysaccharides; homogeneous polysaccharides; pectin polysaccharides; acidic heteropolysaccharides; and arabinogalactans, which are composed of arabinose, glucosamine, galactose, glucose, xylose, mannose, fructose, ribose, galacturonic acid, and glucuronic acid. Pharmacological studies have shown that LBPs exhibit a variety of important biological activities, such as protection of nerves; promotion of reproduction; and anti-inflammatory, hepatoprotective, hypoglycemic, and eyesight-improving activities. The aim this paper is to summarize previous and current references to the isolation process, structural characteristics, and biological activities of the genus Lycium L. polysaccharide. This review will provide a useful reference for further research and application of the genus Lycium L. polysaccharide in the field of functional food and medicine.

Comparative Characterization and Immunomodulatory Activities of Polysaccharides Extracted from the Radix of Platycodon grandiflorum with Different Extraction Methods

Platycodon grandiflorum is an edible and medicinal plant, and polysaccharides are one of its important components. To further improve the utilization rate of P. grandiflorum, we investigated the effects of four different extraction methods, including hot water, ultrasonic-assisted, acid-assisted, and alkali-assisted extractions, on the polysaccharides, which were named PG-H, PG-U, PG-C, and PG-A. The findings indicated that the extraction method had a significant impact on the yield, characteristics, and immunoregulatory activity. We observed that the yields decreased in the following order: PG-H, PG-U, PG-C, and PG-A. Galacturonic acid, glucose, galactose, and arabinose were the most prevalent monosaccharides in the four PGs. However, their proportions varied. In addition, the difference between the content of glucose and galacturonic acid was more significant. PG-U had the highest glucose content, whereas PG-C had the lowest. Galacturonic acid content was highest in PG-A, while the lowest in PG-U. The molecular weight decreased in the order of PG-U, PG-H, PG-C, and PG-A; the particle size was in the order of PG-U, PG-A, PG-H, and PG-C. Moreover, the extraction method had a great impact on immunoregulatory activity. The ability to stimulate the immune function of macrophages was as follows: PG-A > PG-C > PG-U > PG-H. The results indicated that PGs, with lower molecular weights and higher GalA content, exhibited better immune-stimulating activity. And more important the AAE method was a good way to extract polysaccharides from Platycodon grandiflorum for use as a functional product and immunological adjuvant.

Inhibitory Effect of Fermented Flammulina velutipes Polysaccharides on Mice Intestinal Inflammation

To investigate the effect of Flammulina velutipes polysaccharides (FVPs) on mice intestinal inflammation, FVPs were extracted from Flammulina velutipes (FV) using a solid anaerobic fermentation technique. The antioxidant and anti-inflammatory capacities of FVP and fermented FVP (FFVP) induced by lipopolysaccharide (LPS) were investigated in vitro and in vivo. The results showed that the yield of FFVP (9.44%) was higher than that of FVP (8.65%), but the molecular weight (MW) of FFVP (15,702 Da) was lower than that of FVP (15,961 Da). The antioxidant and anti-inflammatory capacities of FFVP were higher than that of FVP in preventing mice diarrhea, enhancing antioxidant capacities, and reducing the secretion and mRNA expression of interleukin-1β (IL-1β), IL-6, IL-18, and tumor necrosis factor-α (TNF-α). The anti-inflammatory mechanisms of FVP and FFVP were analyzed by inhibiting the activation of the NLRP3 signaling pathway using an LPS-induced mice model. This study indicated that FFVP could be used as a functional antioxidant, indicating a potential application in functional food and health products.

The anti-aging activity of Lycium barbarum polysaccharide extracted by yeast fermentation: In vivo and in vitro studies

Lycium barbarum polysaccharide (LBP) is an important active substance in Lycium barbarum. In this study, LBP was extracted by the hot water method and yeast fermentation method to obtain products called LBP-W and LBP-Y, respectively. Both LBPs have a strong ability to scavenge DPPH, hydroxyl, and superoxide anion free radicals and have a total antioxidant capacity. Both LBPs prolong the lifespan of C. elegans under normal conditions, oxidative stress and heat stress and do not affect fertility, LBPs could prolong the lifespan of C. elegans by upregulating the expression of daf-16, sod-3 and hsp-16.2 genes, and LBP-Y is more efficacious. The molecular weight of the LBPs was characterized by gel permeation chromatography (GPC), and the results showed that LBP-Y is smaller and more uniform than LBP-W. The skin penetration experiment showed that the absorption effect of LBP-Y is better than that of LBP-W. These lines of evidence suggest that the yeast fermentation extraction of LBP produces better antioxidant and anti-aging effects than those obtained with the traditional hot water extraction, which is more suitable for obtaining raw materials with anti-aging functions that can potentially be used in the food and cosmetic industries.

High-Pressure Technologies for the Recovery of Bioactive Molecules from Agro-Industrial Waste

Large amounts of food waste are produced each year. These residues require appropriate management to reduce their environmental impact and, at the same time, economic loss. However, this waste is still rich in compounds (e.g., colorants, antioxidants, polyphenols, fatty acids, vitamins, and proteins) that can find potential applications in food, pharmaceutical, and cosmetic industries. Conventional extraction techniques suffer some drawbacks when applied to the exploitation of food residues, including large amounts of polluting solvents, increased time of extraction, possible degradation of the active molecules during extraction, low yields, and reduced extraction selectivity. For these reasons, advanced extraction techniques have emerged in order to obtain efficient residue exploitation using more sustainable processes. In particular, performing extraction under high-pressure conditions, such as supercritical fluids and pressurized liquid extraction, offers several advantages for the extraction of bioactive molecules. These include the reduced use of toxic solvents, reduced extraction time, high selectivity, and the possibility of being applied in combination in a cascade of progressive extractions. In this review, an overview of high-pressure extraction techniques related to the recovery of high added value compounds from waste generated in food industries is presented and a critical discussion of the advantages and disadvantages of each process is reported. Furthermore, the possibility of combined multi-stage extractions, as well as economic and environmental aspects, are discussed in order to provide a complete overview of the topic.

Extraction optimization, physicochemical characterization, and antioxidant activity of polysaccharides from Rhodosorus sp. SCSIO-45730

Microalgal polysaccharides have been reported in many studies due to their uniqueness, biocompatibility, and high value, and Rhodosorus sp. SCSIO-45730 was an excellent source of polysaccharides and β-glucans. However, the polysaccharides from the red unicellular alga Rhodosorus sp. SCSIO-45730 have barely been studied. In this work, hot water extraction of Rhodosorus sp. SCSIO-45730 polysaccharides (RSP) was optimized using response surface methodology (RSM) based on Box-Behnken design (BBD). The maximum RSP yield (9.29%) was achieved under the optimum extraction conditions: liquid-solid ratio of 50.00 mL g^-1; extraction temperature of 84 °C; extraction time of 2 h; and extraction times of 5 times. The results of physicochemical characterization showed that RSP had high sulfate and uronic acid with content of 19.58% and 11.57%, respectively, rough layered structure, and mainly contained glucose, galactose, xylose, and galacturonic acid with mass percentages of 34.08%, 28.70%, 12.46%, and 12.10%. Furthermore, four kinds of antioxidant assays were carried out, and the results indicated that RSP had strong scavenging activities on ABTS and hydroxyl radical and moderate scavenging activities on DPPH and ferrous chelating ability. These results indicated that RSP showed potential as a promising source of antioxidants applied in food, pharmaceutical, and cosmetics industry.

SUPPLEMENTARY INFORMATION

The online version contains supplementary material available at 10.1007/s10811-021-02646-2.

Pharmacokinetics and Excretion Study of Lycium barbarum Polysaccharides in Rats by FITC-Fluorescence Labeling

A high-performance gel permeation chromatography fluorescence detection (HPGPC-FD) method combined with fluorescein isothiocyanate (FITC) labeling was established for the microanalysis of L. barbarum polysaccharides (LBP). The calibration curves linear over the range of 0.2–20 µg/mL in rat plasma, and 0.25–500 μg/mL in urine and feces samples with correlation coefficients greater than 0.99. The inter-day and intra-day precisions (RSD, %) of the method were under 15% with the relative recovery ranging from 84.6% to 104.0% and the RSD ranging from 0.47% to 7.28%. The concentration–time curve of LBP-FITC in plasma following intragastric administration at 100, 50 and 25 mg/kg well fitted to a nonlinear model. LBP-FITC slowly eliminated from plasma according to the long half-lives (t_1/2 = 31.39, 38.09, and 45.76 h, respectively) and mean retention times (MRT_0–t = 18.38, 19.15 and 20.07 h, respectively; AUC_0–∞ = 230.49, 236.18 and 242.57 h, respectively) after administration of LBP-FITC at doses of 100, 50, and 25 mg/kg, respectively. After intragastric administration at 50 mg/kg for 72 h, the concentration of LBP-FITC in urine and feces was 0.09 ± 0.04% and 92.18 ± 3.61% respectively; the excretion rate of urine was the highest in 0–4 h period and decreased continuously in 4–24 h period. The excretion rate of feces was the highest in 4–10 h, 48.28 ± 9.349% in feces within 4–10 h, and decreased rapidly in 10–24 h. The present study showed that LBP was absorbed as its prototype and most proportion of LBP was excreted from feces, indicating a long time remaining in intestine.

Effect of extraction method on the chemical profiles and bioactivities of soybean hull polysaccharides

The yields, properties, and bioactivities of polysaccharides extracted by three methods from soybean hulls (SSCPs) were evaluated: hot water extraction (H-SSCP), microwave-assisted ammonium oxalate extraction (A-SSCP), and microwave-assisted sodium citrate extraction (S-SSCP). A-SSCP gave the highest yield of polysaccharides (9.3 ± 0.5%) although all three products had similar physicochemical characteristics and FT-IR spectra. A-SSCP and S-SSCP produced polysaccharides with lower molecular weight distributions and higher total reducing power and scavenging ability for ABTS+• and DPPH• free radicals. Furthermore, the effect of SSCPs on carbon tetrachloride (CCl4)-induced liver injury was investigated in the mice. When compared with H-SSCP and S-SSCP, A-SSCP significantly decreased the levels of alanine aminotransferase (ALT), aspartate aminotransferase (AST), malondialdehyde (MDA), and reactive oxygen (ROS) to normal (p < .05) and increased the level of glutathione (GSH) to normal (p < .05). A-SSCP was the most effective polysaccharide, yielding an approximately normal hepatic appearance with well-preserved cytoplasm, obvious cell boundaries, with legible nuclei and nucleoli. This study indicates that polysaccharides extracted from soybean hulls via microwave-assisted ammonium oxalate extraction have the potential to be developed as a new functional food contributing to the alleviation of liver damage.

Optimization of the composite enzyme extraction of polysaccharide from Erythronium sibiricum bulb and its immunoregulatory activities

An efficient compound enzyme extraction process was developed and optimized to extract the polysaccharide from Erythronium sibiricum bulb via response surface methodology. The polysaccharide E2P was obtained. Then, the preliminary characteristics of E2P were determined via colorimetry and chromatography. Additionally, the immunoregulatory activities of E2P and another polysaccharide (ESBP, extracted using the hot water method) were compared. The optimized extraction results were as follows: temperature (54.56 °C), time (2.52 h), pH (6.53), and enzyme concentration ratio (0.5% cellulase:1.5% amylase). The yield (64.18% ± 2.91%) obtained under the aforementioned conditions was considerably higher than the yield of ESBP (37.25% ± 0.17%). The total sugar, uronic acid, starch, and protein contents of E2P were 81.77% ± 2.84%, 3.31% ± 0.45%, 3.29% ± 0.01%, and 0.24% ± 0.02%, respectively. The HPLC result suggested that the predominant monosaccharides of E2P included glucose, galactose, and arabinose, with a molar ratio of 543.2:1:1.8. The in vitro tests in RAW264.7 cells indicated that ESBP exhibited better immunomodulatory activities than E2P. In particular, ESBP can promote the proliferation, phagocytosis, and cytokine secretion abilities of cytokines, such as nitric oxide, tumor necrosis factor-α, and interleukin (IL)-1β of RAW264.6 cells. By contrast, E2P can only promote phagocytosis ability and the secretion of IL-1β.

Characterization, antioxidant activities, and inhibition on α-glucosidase activity of corn silk polysaccharides obtained by different extraction methods

The polysaccharides (CSPw, CSPc, CSPa, and CSPu) were prepared by hot water extraction, acid-assisted extraction, alkaline-assisted extraction, and ultrasound-assisted extraction from corn silk, respectively. High performance gel permeation chromatography (HPGPC), fourier-transform infrared (FT-IR) spectroscopy, and scanning electron microscopy (SEM) results indicated that the extraction methods had an obvious impact on the molecular weight, structure, and morphology of the CSPs. Among the four polysaccharides, CSPu showed the highest inhibitory α-glucosidase activity, which might be related to its smaller molecular weight. Furthermore, kinetics analyses revealed that CSPu had significant inhibition of α-glucosidase in a non-reversible and competitive manner. Fluorescence quenching analysis illustrated that the interaction mechanism of CSPu and α-glucosidase was claimed as a static quenching mechanism. Isothermal titration calorimetry (ITC) analysis showed that the main driving forces for the interaction of CSPu with α-glucosidase was hydrogen bonding and the binding interactions of them occurred spontaneously.

Effect of the structural characterization of the fungal polysaccharides on their immunomodulatory activity

The immunomodulatory effects of the four extracellular polysaccharides, namely WPA, WPB, AP2A, and TP1A, which were isolated from the fermented broth of Aspergillus aculeatus, A. terreus and Trichoderma sp. KK19L1, were investigated in vitro. WPA, WPB, AP2A, and TP1A were not toxic to RAW264.7 cells. These polysaccharides enhanced cell viability. WPA, WPB, AP2A, and TP1A showed increased immunomodulatory effect by strengthening the phagocytic activity and enhancing the release of NO, TNF-α and IL-6 from RAW264.7 cells. WPA, WPB, AP2A, and TP1A exhibited different immunomodulatory activity in vitro due to their different structural characterizations, and their immunoregulatory effects decreased successively in the following order: WPA, WPB, AP2A, and TP1A. The extracellular polysaccharides WPA, WPB, AP2A, and TP1A had potent immunomodulatory effects and could be used as potential immunomodulatory agents in the fields of functional food and medicine.