Physicochemical characteristics and biological activities of polysaccharides from the leaves of different loquat (Eriobotrya japonica) cultivars

A review: Polysaccharides targeting mitochondria to improve obesity

Polysaccharides are one of the most important and widely used bioactive components of natural products, which can be used to treat metabolic diseases. Natural polysaccharides (NPs) have been the subject of much study and research in the field of treating obesity in recent years. Studies in the past have demonstrated that mitochondria are important for the initiation, progression, and management of obesity. Additionally, NPs have the ability to improve mitochondrial dysfunction via a variety of mechanisms. This review summarized the relationship between the structure of NPs and their anti-obesity activity, focusing on the anti-obesity effects of these compounds at the mitochondrial level. We discussed the association between the structure and anti-obesity action of NPs, including molecular weight, monosaccharide composition, glycosidic linkage, conformation and extraction methods. Furthermore, NPs can demonstrate a range of functions in adipose tissue, including but not limited to improving the mitochondrial oxidative respiratory chain, inhibiting oxidative stress, and maintaining mitochondrial mass homeostasis. The purpose of this work is to acquire a thorough understanding of the function that mitochondria play in the anti-obesity effects of NPs and to offer fresh insights for the investigation of how NPs prevent obesity and the creation of natural anti-obesity medications.

Ultrasound-assisted deep eutectic solvents extraction of polysaccharides from Loquat leaf: Process optimization and bioactivity study

Loquat leaves are the by-product of loquat fruit production. Polysaccharides are one of the main active ingredients in loquat leaves. In this study, polysaccharides were extracted from loquat leaves by ultrasonic-assisted deep eutectic solvents (DESs) extraction method. Further, the extracted crude loquat leaf polysaccharides (CLLP) were purified and separated via S-8 resin and DEAE-52 cellulose column chromatography, respectively. Additionally, the effects of polysaccharides on activity of sperm in boar semen preserved in medium at 17 °C, were evaluated preliminarily. DES, composed of choline chloride/ethylene glycol (1:6, molar ratio), was proved to be the suitable solvent for LLP extraction. The optimized extraction conditions were water content 44 %, liquid-solid ratio 1:29 (g/g), extraction temperature 61 °C and extraction time 98 min. Under these conditions, the LLP yield was 57.82 ± 1.50 mg/g. A homogeneous polysaccharide (LLP1-2, Mw: 2.17 × 104 Da) was isolated from CLLP. Its total sugar, uronic acid and protein contents were 76.31 ± 1.25 %, 14.19 ± 0.67 % and 3.28 ± 0.42 %, respectively. Further, 800 μg/mL LLP1-2 could effectively enhance the antioxidant activity of sperm. This study laid a foundation for DESs and column chromatography in the field of polysaccharide extraction and separation, proving that LLP can be used as a natural antioxidant for sperm preservation.

From by-products to new application opportunities: the enhancement of the leaves deriving from the fruit plants for new potential healthy products

In the last decades, the world population and demand for any kind of product have grown exponentially. The rhythm of production to satisfy the request of the population has become unsustainable and the concept of the linear economy, introduced after the Industrial Revolution, has been replaced by a new economic approach, the circular economy. In this new economic model, the concept of "the end of life" is substituted by the concept of restoration, providing a new life to many industrial wastes. Leaves are a by-product of several agricultural cultivations. In recent years, the scientific interest regarding leaf biochemical composition grew, recording that plant leaves may be considered an alternative source of bioactive substances. Plant leaves' main bioactive compounds are similar to those in fruits, i.e., phenolic acids and esters, flavonols, anthocyanins, and procyanidins. Bioactive compounds can positively influence human health; in fact, it is no coincidence that the leaves were used by our ancestors as a natural remedy for various pathological conditions. Therefore, leaves can be exploited to manufacture many products in food (e.g., being incorporated in food formulations as natural antioxidants, or used to create edible coatings or films for food packaging), cosmetic and pharmaceutical industries (e.g., promising ingredients in anti-aging cosmetics such as oils, serums, dermatological creams, bath gels, and other products). This review focuses on the leaves' main bioactive compounds and their beneficial health effects, indicating their applications until today to enhance them as a harvesting by-product and highlight their possible reuse for new potential healthy products.

Effect of hydrochloric acid and citric acid with ultrasound processing on characteristics of superfine-ground pectic polysaccharides from okra (Abelmoschus esculentus L.) peel

The structural properties and biological activities of okra pectic polysaccharides (OPs) were impacted by various extraction methods. Based on commonly grinding (40, 100 meshes) and superfine grinding okra powders, two extraction solvents (hydrochloric acid, HA; citric acid, CA) were used firstly. Next, the extraction yield, physical and chemical properties, molecular structure and functional properties of OPs were analyzed by non-ultrasonic treatment and ultrasound-assisted superfine grinding method. The outcomes demonstrated that the extraction yield of OPs rose as the particle size of the powder decreased. HA-OPs had higher molecular weight (Mw), apparent viscosity and emulsification ability than CA-OPs. CA-OPs had higher esterification degree (DE), solubility and total sugar content, and higher amounts of rhamnogalacturonan-I (RG-I) segments. Compared with OPs without ultrasound-assisted extraction, ultrasound-assisted superfine grinding extraction exhibited higher sugar content, antioxidant capacity, emulsification ability, lower Mw, DE and apparent viscosity. Finally, the correlation between structure and function of OPs was further quantified. The antioxidant capacity was positively correlated with RG-I content, and negatively correlated with DE and Mw. The emulsification ability was mainly positively correlated with the GlcA of OPs. This study provides a theoretical basis for the development of OPs foods with clear structure-function relationship, which would be instructive for the application of OPs in food and cosmetics.

Effects of different extraction methods on the physico-chemical characteristics and biological activities of polysaccharides from Clitocybe squamulosa

This study comparatively evaluated the effects of the commonly used six extraction methods (acidic, alkaline, enzymatic, ultrasonic, high-pressure, and microwave) on the physico-chemical properties, processing characteristics, and biological activities of polysaccharides from Clitocybe squamulosa (CSFPs). The results show that polysaccharides extracted using an enzyme-assisted extraction method has a relatively high extraction yield (4.46 ± 1.62 %) and carbohydrate content (70.79 ± 6.25 %) compared with others. Furthermore, CSFPs were all composed of glucose, galactose, mannose, xylose, and glucosamine hydrochloride. Only ultrasonic-assisted extraction of polysaccharides (CSFP-U) has a triple helix chain conformation. Scanning electron microscopy (SEM) revealed significant differences in the microstructure of polysaccharides prepared using different methods. Besides that, the polysaccharides prepared by alkali extraction (CSFP-B) and high-pressure assisted extraction (CSFP-H) have good water (2.86 ± 0.29 g/g and 3.15 ± 0.29 g/g) and oil (8.13 ± 0.32 g/g and 7.97 ± 0.04 g/g) holding properties. The rheological behavior demonstrated that CSFPs solutions were typical non-Newtonian fluid. Apart from this, the antioxidant capacity (clearing DPPH (IC50 = 0.29) and ABTS free radicals (IC50 = 0.19), total reduction ability (IC50 = 3.02)) of polysaccharides prepared by the microwave-assisted extraction (CSFP-M) method was significantly higher than that of other extraction methods. By contrast, the polysaccharide prepared by acid extraction (CSFP-A) has the optimum binding capacity (bile acid salt (71.30 ± 6.78 %) and cholesterol (57.07 ± 3.26 mg/g)). The antibacterial activity of CSFPs was positively correlated with their concentration. Thus, the research results can provide a theoretical basis for the development and utilization of polysaccharides from C. squamulosa.

Green extraction of polysaccharides from Camellia oleifera fruit shell using tailor-made deep eutectic solvents

Camellia oleifera fruit shells are often discarded as byproducts in the C. oleifera industry. There is a general interest in isolating high-value natural products to valorize those fruit shells with green, rapid, and effective extraction methods. This study employed 43 combinations of deep eutectic solvents (DESs) to extract polysaccharides from C. oleifera fruit shells. Two choline chloride-based DESs and a ternary DES with propionic acid and 1,3-butanediol as hydrogen bond donors exhibited relatively high extraction efficiency. The polysaccharide yield reached 15.03 ± 0.35 % under optimized extraction time (55 min), extraction temperature (70 °C), and DES water content (33.33 %). The physicochemical composition and preliminary structure of obtained polysaccharides were characterized. Additionally, DESs-extracted polysaccharides exhibited higher in vitro antioxidant activities and hypoglycemic effects compared to water-extracted polysaccharides. These findings suggested that the optimized DES-assisted extraction method could be a potential approach for polysaccharides extraction from C. oleifera.

Ultrasonic effects on the degradation kinetics, structural characteristics and protective effects on hepatocyte lipotoxicity induced by palmitic acid of Pueraria Lobata polysaccharides

In this study, a high-molecular-weight Pueraria lobata polysaccharide (PLP) with a molecular weight of 273.54 kDa was degraded by ultrasound, and the ultrasonic degradation kinetics, structural characteristics and hepatoprotective activity of ultrasonic degraded PLP fractions (PLPs) were evaluated. The results showed that the ultrasonic treatment significantly reduced the Mw and particle size of PLP, and the kinetic equation of ultrasonic degradation of PLP followed to the midpoint fracture model (the fist-order model). The monosaccharide composition analysis, FT-IR, triple helix structure and XRD analysis all indicated that the ultrasound degradation did not destroy the primary structure of PLP, but the thermal stability of degraded fractions improved. Additionally, the scanning electron microscopy analysis demonstrated that the surface morphology of PLP was altered from smooth, flat, compact large flaky structure to a sparse rod-like structure with sparse crosslinking (PLP-7). The degraded PLP fractions (0.5 mg/mL) with lower Mw exhibited better antioxidant activities and protective effects against palmitic acid-induced hepatic lipotoxicity, which may be due to the increased exposure of active groups such as hydroxyl groups of PLP after ultrasound. Further investigation showed that PLPs not only increased Nrf2 phosphorylation and its nuclear translocation, thereby activating Nrf2/Keap1 signaling pathway, but also enhanced HO-1, NQO-1, γ-GCL gene expressions and promoted superoxide dismutase and catalase activities, which protected hepatocytes against PA-induced oxidative stress and lipotoxicity. Overall, our research might provide an in-depth insight into P. Lobata polysaccharide in ameliorating lipid metabolic disorders, and the results revealed that ultrasonic irradiation could be a promising degradation method to produce value-added polysaccharide for use in functional food.

Effect of in vitro simulated digestion and fecal fermentation on Boletus auripes polysaccharide characteristics and intestinal flora

Boletus auripes is edible and medicinal boletus mushrooms rich in diverse nutrients and bioactive compounds, of which indigestible dietary polysaccharides are the most abundant compounds involved the regulation of gut microbes. However, the physicochemical, digestive, and fermentation characteristics of Boletus auripes polysaccharide (BAP) are not well studied. This study aimed to investigate the influence of different digestive stages on BAP's physicochemical characteristics and biological activities, and its effect on intestinal flora. We found that mannose (0.23 %), glucose (0.31 %), galactose (0.17 %), and fucose (0.19 %) were the main monosaccharides of BAP, with a high-molecular-weight (Mw) and a low-Mw fraction of 2084.83 and 62.93 kDa, respectively. During the course of digestion, there were slight alterations in the chemical composition, monosaccharide composition, and Mw of BAP. Despite these changes, the fundamental structural features of BAP remained largely unaffected. Moreover, the antioxidant and hypoglycemic activities of BAP were weakened under simulated saliva-gastrointestinal digestion. However, gut microbiota decomposed and utilized BAP to generate various short-chain fatty acids during fermentation, which decreased the pH of fecal cultures. Meanwhile, BAP modulated the gut microbiota composition and increased the relative abundance of Bacteroidetes. These findings suggest that BAP have potential for maintaining intestinal health and protecting against interrelated diseases.

Comparison of physicochemical characteristics, antioxidant and immunomodulatory activities of polysaccharides from wine grapes

In this study, an efficient ultrasonic-assisted extraction method was used for the extraction and optimization of four wine grape polysaccharides. A three-level, three-factor Box Behnken Design combined with the response surface approach was used to optimize the extraction conditions. Their physicochemical properties, molecular structure, antioxidant activity, immunomodulatory activity and hepatoprotective effects were examined and compared. These findings suggest that the four wine grape polysaccharides share similar basic structural features and monosaccharide composition. Furthermore, four wine grape polysaccharides exhibited antioxidant and immunomodulatory activities in a concentration-dependent manner. Moldova (MD) polysaccharide displayed better antioxidant activity and immunomodulatory ability. Furthermore, MD polysaccharide has a significant therapeutic effect on CCl₄-induced rat liver injury by improving the antioxidant defense system and inhibiting oxidative stress, indicating that MD has a hepatoprotective effect. Taken together, the MD wine grape polysaccharide may have potential applications in prevention of liver disease in the functional food and pharmaceutical industries.

Organic Acid Accumulation and Associated Dynamic Changes in Enzyme Activity and Gene Expression during Fruit Development and Ripening of Common Loquat and Its Interspecific Hybrid

Loquats have gained increasing attention from consumers and growers for their essential nutrients and unusual phenology, which could help plug a gap period at market in early spring. Fruit acid is a critical contributor to fruit quality. The dynamic changes in organic acid (OA) during fruit development and ripening of common loquat (Dawuxing, DWX) and its interspecific hybrid (Chunhua, CH) were compared, as well as the corresponding enzyme activity and gene expression. At harvest, titratable acid was significantly lower (p ≤ 0.01) in CH (0.11%) than in DWX loquats (0.35%). As the predominant OA compound, malic acid accounted for 77.55% and 48.59% of the total acid of DWX and CH loquats at harvest, followed by succinic acid and tartaric acid, respectively. PEPC and NAD-MDH are key enzymes that participate in malic acid metabolism in loquat. The OA differences in DWX loquat and its interspecific hybrid could be attributed to the coordinated regulation of multiple genes and enzymes associated with OA biosynthesis, degradation, and transport. The data obtained in this work will serve as a fundamental and important basis for future loquat breeding programs and even for improvements in loquat cultural practices.

Physicochemical characteristics and biological activities of soluble dietary fibers isolated from the leaves of different quinoa cultivars

Quinoa leaf is consumed as a promising value-added vegetable in the diet. Although quinoa leaf is rich in soluble dietary fibers, the knowledge regarding their chemical structures and biological activities is still limited, which astricts their application in the functional food industry. Thus, to improve the precise use and application of soluble dietary fibers (SDFs) isolated from quinoa leaves in the food industry, the physicochemical structures and bioactivities of SDFs isolated from different quinoa leaves were systematically investigated. Results indicated that quinoa leaves were rich in SDFs, ranging from 3.30 % to 4.55 % (w/w). Quinoa SDFs were mainly composed of acidic polysaccharides, such as homogalacturonan and rhamnogalacturonan I, which had the molecular weights in the range of 4.228 × 10⁴ -7.059 × 10⁴ Da. Besides, quinoa SDFs exerted potential in vitro antioxidant activities, lipid and bile acid-adsorption capacities, immunoregulatory activities, and prebiotic effects, which might be partially associated with their molecular mass, content of uronic acid, and content of bound polyphenol. Collectively, these findings are beneficial to better understanding the chemical structures and bioactivities of SDFs extracted from different quinoa leaves, which can also provide a scientific basis for developing quinoa SDFs into functional foods in the food industry.

Physicochemical characteristics and biological activities of grape polysaccharides collected from different cultivars

In this study, four wine grape polysaccharides were extracted and optimized by using an efficient ultrasound-assisted extraction. A three-level, three-factor Box Behnken Design (BBD) combining with response surface methodology (RSM) was employed to optimize the extraction conditions including ultrasonic power, ultrasonic time and liquid-to-solid ratio. Furthermore, their physicochemical structures, antioxidant and liver protective activity were investigated and compared. Results revealed that the functional groups and monosaccharide compositions of these grape polysaccharides collected from different varieties were similar. Nevertheless, their molecular weights, molar ratios of monosaccharide compositions and surface morphological features were different. And the antioxidant activities of these polysaccharides were screened by free radical scavenging test. 'Beichun' (BC) and 'Benni fuji' (BF) polysaccharides possessed better antioxidant function. Further, the in vivo evaluation indicated that the polysaccharides of BC and BF have a protective effect against myocardial I/R injury in mice by inhibiting myocardial necroptosis mediated by mitochondrial ROS generation. Therefore, BC and BF grapes have potential applications in the medical and food industries.

Hybrid techniques of pre and assisted processing modify structural, physicochemical and functional characteristics of okra pectin: Controlled-temperature ultrasonic-assisted extraction from preparative dry powders and its field monitoring

Diversiform okra dry powders were prepared and controlled-temperature ultrasonic-assisted extraction (CTUAE) was then utilized to obtain okra pectin (OP) from the preparative powders. During processing of hybrid techniques, 6 types of dry powders were prepared through different drying technologies (hot air drying, HD; freeze-drying, FD) and meshes (60, 80, 120 meshes) at first. Next, the extraction yield, physicochemical and function characteristics, and molecular structure of OP were analyzed with or without CTUAE technique. Meanwhile, the time-frequency domains of acoustic fields during extraction process of OP were monitored to analyze the effects of ultrasonic fields. Results showed that OP main chains with less cracking by FD than that by HD; the yield, GalA, esterification degree (DE), M_w and viscosity of OP increased, but its particle size decreased. Water holding capacity (WHC) and oil holding capacity (OHC) of OP by HD were more prominent. Secondly, HD OP had dendritic rigid chains, while FD OP had flexible chains with multiple branches. For HD OP, as meshes of okra dry powders decreased, GalA, viscosity and emulsification ability decreased; while gel strength and thermal stability increased. For FD OP, the reduction of meshes improved thermal stability. Above all, CTUAE technique increased the yield and GalA, and decreased DE, M_w and particle size of OP. In terms of functional characteristics, the technique also improved gel strength, resilience and viscoelasticity, enhanced emulsifying stability, WHC and thermal stability, and reduced viscosity. Finally, the correlation between functional and structural characteristics of OP was quantified, and some suggestions were made for its application in food areas.

Two Novel Polysaccharides From Clitocybe squamulosa: Their Isolation, Structures, and Bioactivities

The crude polysaccharides from the fruiting bodies of Clitocybe squamulosa (CSFP) were isolated by hot-water extraction. Two novel polysaccharides, CSFP1-β and CSFP2-α, were further purified by DEAE-52 anion exchange and Sephacryl S-400 gel filtration chromatography, and the purities reached 98.44 and 97.83%, respectively. The structural characteristics and bioactivities of CSFP, CSFP1-β, and CSFP2-α were identified by the combination of chemical and instrumental analysis. Results showed that CSFP was formed by the aggregation of honeycomb spherical materials; CSFP1-β and CSFP2-α were interwoven by reticular and fibrous structures, respectively. Purified components of both CSFP1-β and CSFP2-α showed typical infrared absorption peaks of polysaccharides, and contents of nucleic acid and protein decreased significantly. Simultaneously, CSFP with a molecular weight (Mw) of 1.948 × 10⁴ Da were composed mainly of glucose, mannose, galactose, and rhamnose. CSFP1-β was composed mainly of glucose, galactose, and mannose, while CSFP2-α was composed of glucose, and both their Mw distributions were uneven. Compared with CSFP, the antioxidant activities of CSFP1-β and CSFP2-α were significantly improved (p < 0.05), and they both showed good abilities to bind free cholesterol and bile acid salts in vitro. The binding abilities of the two compounds were found to be 68.62 and 64.43%, and 46.66 and 45.05 mg/g, respectively. CSFP, CSFP1-β, and CSFP2-α had good bacteriostatic effects with a linear increasing relationship to increasing concentration. In addition, CSFP promoted the growth of RAW264.7 cells and has potential immunomodulatory, anti-inflammatory, and anti-tumor activities.

Effects of loquat (Eriobotrya japonica Lindl.) leaf extract with or without ascorbic acid on the quality characteristics of semi-dried restructured jerky during storage

Deterioration of jerky during storage is a major concern; this is usually combated with natural or synthetic antioxidants. This study aimed to evaluate the quality characteristics of semi-dried restructured jerky with and without loquat leaf extract (LE) powder and ascorbic acid (AA) during storage for 180 days. The jerkies were formulated with 0%, 0.15%, and 0.3% LE and/or 0.05% AA (Control, no antioxidant; AA, 0.05% AA; LE 0.15, 0.15% loquat LE; LE 0.15-AA, 0.15% loquat LE+0.05% AA; LE 0.3, 0.3% loquat LE; LE0.3-AA, 0.3% loquat LE+0.05% AA). LE is a phenolic compound, whose 1,1-diphenyl-2-picrylhydarzyl radical scavenging activity and metal chelating activity were found to be higher than AA. All antioxidant combinations having higher LE concentration and containing AA were effective in delaying protein and lipid oxidation compared to the control or AA. At the end of storage period, LE 0.15-AA and AA had higher CIE a* and lower shear force than the control. Therefore, the combination of 0.15% LE and 0.05% AA can result in reduced protein and lipid oxidation without any negative effect on the quality characteristics of semi-dried restructured jerky.

Effect of in vitro simulated gastrointestinal digestion on the antioxidant activity, molecular weight, and microstructure of polysaccharides from Chinese yam

In this study, we investigated the antioxidant properties and the changes of molecular weight (Mw), antioxidant activity, and microstructure of Chinese yam polysaccharides (CYP-A) during in vitro digestion. Results showed that the scavenging rate of 2, 2-diphenyl-1-picrylhydrazyl (DPPH) free radical of CYP-A was approximately 79% at the concentration of 6 mg/mL. Furthermore, the antioxidant ability positively correlated with the concentration of CYP-A. In addition, the Mw of CYP-A decreased (p < 0.05) after intestinal digestion. Fourier transform infrared showed that the degrees of esterification of CYP-A increased to 39.04% after 6 h of gastric digestion. Moreover, the structure of CYP-A changed after in vitro gastric digestion. The scanning electron microscope (SEM) images indicated that the surface morphology of CYP-A turned from smooth and irregular to a layered honeycomb after gastrointestinal digestion in vitro. Surprisingly, the activity of DPPH radical scavenging significantly increased (p < 0.05) in the intestinal digested samples of CYP-A, which showed a positive correlation with the concentration of CYP-A. However, the reducing power significantly decreased (p < 0.05) after in vitro intestinal digestion.

In vitro digestion and fermentation by human fecal microbiota of polysaccharides from Clitocybe squamulose

The present study aimed to evaluate the effects of in vitro simulated saliva-gastrointestinal digestion and fecal fermentation behavior on the chemical composition, structure and bioactivity of polysaccharides from Clitocybe squamulosa (CSFP). Results showed that gastric digestion significantly changed the chemical composition and structural properties of CSFP, such as total uronic acid, reducing sugar, molecular weight, rheological properties, particle size, and microscopic morphology. In particular, the molecular weight decreased from 19,480 Da to 10,945 Da, while the reducing-sugar content increased from 0.149 mg/mL to 0.293 mg/mL. Gastric digestion also affected the biological activity of CSFP. Although after gastric digestion, CSFP retained its vigorous antioxidant activity, ability to inhibit α-amylase activity, and the binding ability to bile acid, fat, and free cholesterol in vitro. However, there was an apparent weakening trend. After in vitro fermentation of gut microbiota, the content of total sugar was significantly decreased from 11.6 mg/mL to 2.4 mg/mL, and the pH value in the fecal culture significantly decreased to 5.20, indicating that CSFP could be broken down and utilized by gut microbiota. Compared to the blank, the concentrations of total short-chain fatty acids (SCFAs) including acetic, propionic and n-butyric significantly increased. Simultaneously, CSFP could remarkably reduce the proportions of Firmicutes and Bacteroides (F/B) and promote the growth of some beneficial intestinal microbiota. Therefore, CSFP can potentially be a new functional food as prebiotics to promote human gut health.

Extraction and identification of proanthocyanidins from the leaves of persimmon and loquat

Proanthocyanidins is flavan-3-ol polymers with many activities which attracted a lot of attention. However, most of the proanthocyanidins come from fruits and seeds, resulting in higher costs. The extraction of proanthocyanidins from leaves that were trimmed as wastes from fruit trees is of good economic benefits. The proanthocyanidins in persimmon leaves and loquat leaves were extracted and purified. The purity of persimmon and loquat leaves were 85.33 ± 0.11% and 88.45 ± 0.96% with yield of 3.40% and 2.37% respectively. Detailed structure information was analyzed. Persimmon leaves proanthocyanidins mainly consist of catechin with B-type link along with a small portion of gallocatechin, catechin gallate and A-type link. Loquat leaves proanthocyanidins consist of catechin, gallocatechin, gallocatechin gallate and afzelechin with B-type link along with a small portion of A-type link. The α-amylase inhibition effect of the two leaves was analyzed. Persimmon leaves proanthocyanidins and loquat leaves proanthocyanidins were two mixed-type inhibitors to α-amylase.

Effects of combined ultrasonic and microwave vacuum drying on drying characteristics and physicochemical properties of Tremella fuciformis

This study analyzes the effects of ultrasonic waves on the drying kinetics of Tremella fuciformis during microwave vacuum drying. The physicochemical properties and structural characteristics of T. fuciformis polysaccharides (TFPs) were studied by drying tremella samples using hot air drying (HAD), microwave vacuum drying, ultrasonic pretreatments with microwave vacuum drying (US + MVD), and air-borne ultrasonic pretreatments combined with microwave vacuum drying (USMVD) under acoustic energy densities of 0.14, 0.28, and 0.42 W/mL. The results showed that USMVD and US + MVD accelerated the mass transfer process of T. fuciformis. Compared with HAD treatment, TFP samples obtained by USMVD and US + MVD had a reduced molecular weight to a certain extent, and they had stronger shear thinning ability. In addition, USMVD-TFPs at 0.42 W/mL retained higher total sugar, reducing sugar, and uronic acid, and the degree of reduction in the monosaccharide component content was small.

High-Efficiency Production of Auricularia polytricha Polysaccharides Through Yellow Slurry Water Fermentation and Its Structure and Antioxidant Properties

Yellow slurry water is a kind of nutrient-rich wastewater of tofu. Firstly, the medium of yellow slurry was optimized. Then, APP40, APP60, and APP80 were obtained by sedimentation with different concentration of ethanol (40, 60, and 80%). The physicochemical properties and primary structures of the three polysaccharides were studied by high performance anion exchange chromatography (HPAEC), high performance gel filtration chromatography (HPGFC), scanning electron microscope (SEM), atomic force microscope (AFM), and Fourier transform infrared (FT-IR) spectrometer. Finally, the effects of three polysaccharides on antioxidation activity were studied. According to the experimental optimization the results, the biomass and the production of Auricularia polytricha Polysaccharides (APPS) reached the peak, and they were 13.5 ± .655 and 9.42 ± .253 g/L (p < .05). The SEM and the AFM showed that the height of APP80 gradually increased from 31.1 to 46.7 nm and from APP40 to APP80. The particle size of APP80 increased, the pores decrease or even disappear, and the molecules begin to aggregate. The FT-IR spectrum analysis showed that the three polysaccharides possessed key functional groups. The carbohydrate content of APP40, APP60, and APP80 was 20.2, 34.25, and 31.73%. The molecular weights of APP40, APP60, and APP80 are 9.462 × 10⁴, 8.742 × 10⁴, and 8.091 × 10⁴ Da, respectively. The three polysaccharides were composed of rhamnose, galactose, glucose, mannose, and xylose but with different molar ratio. APP80 showed strong reducing ability and scavenging activity of 2,2–diphenyl–1–picrylhydrazyl (DPPH) and hydroxyl radicals through antioxidant activities evaluated in vitro. This study introduces a way for the effective use of yellow slurry water.

A functional polysaccharide from Eriobotrya japonica relieves myocardial ischemia injury via anti-oxidative and anti-inflammatory effects

We herein report a food-derived polysaccharide (EJP) with the effect of relieving myocardial ischemia reperfusion injury (MIRI). This novel polysaccharide was isolated from the leaf of Eriobotrya japonica, and we first found its myocardium protective effects in vitro. Then, we firstly characterized EJP with a series of analytical technologies and further tested its effect on myocardial ischemia reperfusion injury (MIRI) with the illustration of the potential mechanisms in vivo. Interestingly, in the murine model of MIRI, administration of EJP effectively improved post-I/R heart contraction and limited the infarct size. Moreover, EJP significantly attenuated IR-induced oxidative damage and inflammatory reaction, as evidenced by decreasing MDA, IL-6, and TNF-α contents and increasing SOD activity and GSH-Px expression. In addition, we proved that EJP not only had no nephrotoxicity but also demonstrated a protective effect on the kidneys through HE staining and biochemical analysis. In sum, EJP, with a significant protective effect against myocardial I/R injury by showing anti-inflammatory and anti-oxidative activities, may become a meaningful drug candidate for the treatment of myocardial I/R injury.

Structure features, selenylation modification, and improved anti-tumor activity of a polysaccharide from Eriobotrya japonica

A homogeneous polysaccharide, EJP90-1, was isolated from the leaves of E. japonica by hot water extraction in this study. EJP90-1 (7702 Da) was a heteropolysaccharide mainly consisting of →5)-linked-α-L-Araf-(1→, →4)-linked-β-D-Manp-(1→, →2,4)-linked-α-L-Rhap-(1→, →4)-linked-α-D-Xylp-(1→, →4)-linked-β-D-Galp-(1→, →2)-linked-β-D-Galp-(1→, →6)-linked-β-D-Glcp-(1→, α-D-Glcp-(4→, and t-linked-α-L-Araf. EJP90-1 was found to show moderate anti-tumor activity at the cellular level. In order to improve the anti-tumor activity and the potential applications of EJP90-1, a typical sodium selenite-nitric acid (Na₂SeO₃-HNO₃) modification on EJP90-1 was carried out. X-ray photoelectron spectroscopy (XPS) and energy dispersive spectrometer (EDS) analysis confirmed that Se was successfully introduced into the polymer chain of EJP90-1. The subsequent in vitro cytotoxicity evaluation showed the selenylation modification derivative (EJP90-1-Se) possessed significant antiproliferative activity against cancer cells (HepG2 and A549 cells) through inducing cell apoptosis. The anti-tumor activity of EJP90-1-Se was further confirmed by zebrafish models, which inhibited the proliferation and migration of HepG2 cells and the angiogenesis.

A draft genome, resequencing, and metabolomes reveal the genetic background and molecular basis of the nutritional and medicinal properties of loquat (Eriobotrya japonica (Thunb.) Lindl)

Loquat (Eriobotrya japonica) is a popular fruit and medicinal plant. Here, a high-quality draft genome of the E. japonica 'Big Five-pointed Star' cultivar that covers ~98% (733.32 Mb) of the estimated genome size (749.25 Mb) and contains a total of 45,492 protein-coding genes is reported. Comparative genomic analysis suggests that the loquat genome has evolved a unique genetic mechanism of chromosome repair. Resequencing data from 52 loquat cultivars, including 16 white-fleshed and 36 yellow-fleshed variants, were analyzed, and the flower, leaf, and root metabolomes of 'Big Five-pointed Star' were determined using a UPLC-ESI-MS/M system. A genome-wide association study identified several candidate genes associated with flesh color in E. japonica, linking these phenotypes to sugar metabolism. A total of 577 metabolites, including 98 phenolic acids, 95 flavonoids, and 28 terpenoids, were found, and 191 metabolites, including 46 phenolic acids, 33 flavonoids, and 7 terpenoids, showed no differences in concentration among the leaves, roots, and flowers. Candidate genes related to the biosynthesis of various medicinal ingredients, such as phenolics, flavonoids, terpenoids, and polysaccharides, were identified. Some of these genes were confirmed to be members of expanding gene families, suggesting that the high concentrations of beneficial metabolites in loquat may be associated with the number of biosynthetic genes in this plant. In summary, this study provides fundamental molecular insights into the nutritional and medical properties of E. japonica.

Changes in Physicochemical and Biological Properties of Polyphenolic-Protein-Polysaccharide Ternary Complexes from Hovenia dulcis after In Vitro Simulated Saliva-Gastrointestinal Digestion

The present study aimed to explore the impacts of in vitro simulated saliva-gastrointestinal digestion on physicochemical and biological properties of the polyphenolic-protein-polysaccharide ternary complex (PPP) extracted from Hovenia dulcis. The results revealed that the in vitro digestion did remarkably affect physicochemical properties of PPP, such as content of reducing sugar release, content of bound polyphenolics, and molecular weight distribution, as well as ratios of compositional monosaccharides and amino acids. In particular, the content of bound polyphenolics notably decreased from 281.93 ± 2.36 to 54.89 ± 0.42 mg GAE/g, which might be the major reason for the reduction of bioactivities of PPP after in vitro digestion. Molecular weight of PPP also remarkably reduced, which might be attributed to the destruction of glycosidic linkages and the disruption of aggregates. Moreover, although biological activities of PPP obviously decreased after in vitro digestion, the digested PPP (PPP-I) also exhibited remarkable in vitro antioxidant and antiglycation activities, as well as in vitro inhibitory effects against α-glucosidase. These findings can help to well understand the digestive behavior of PPP extracted from H. dulcis, and provide valuable and scientific supports for the development of PPP in the industrial fields of functional food and medicine.

Physicochemical and Biological Properties of Polysaccharides from Dictyophora indusiata Prepared by Different Extraction Techniques

In this study, different extraction techniques, including traditional hot water extraction (HWE), microwave-assisted extraction (MAE), pressurized assisted extraction (PAE), and ultrasonic-assisted extraction (UAE), were used to extract Dictyophora indusiata polysaccharides (DFPs), and their physicochemical and biological properties were compared. Results revealed that extraction yields of D. indusiata polysaccharides prepared by different extraction techniques ranged from 5.62% to 6.48%. D. indusiata polysaccharides prepared by different extraction techniques possessed similar chemical compositions and monosaccharide compositions, while exhibited different molecular weights (M_w), apparent viscosities, and molar ratios of constituent monosaccharides. In particularly, D. indusiata polysaccharides prepared by HWE (DFP-H) had the highest M_w and apparent viscosity among all DFPs, while D. indusiata polysaccharides extracted by UAE (DFP-U) possessed the lowest M_w and apparent viscosity. In addition, the in vitro antioxidant effects of D. indusiata polysaccharides prepared by PAE (DFP-P) and DFP-U were significantly higher than that of others. Indeed, both DFP-P and DFP-H exhibited much higher in vitro binding properties, including fat, cholesterol, and bile acid binding properties, and lipase inhibitory effects than that of D. indusiata polysaccharides prepared by MAE (DFP-M) and DFP-U. These findings suggest that the PAE technique has good potential for the preparation of D. indusiata polysaccharides with desirable bioactivities for the application in the functional food industry.

Post-screening characterization of an acidic polysaccharide from Echinacea purpurea with potent anti-inflammatory properties in vivo

We extracted and purified three polysaccharides from Echinacea purpurea using pectinase-assisted extraction to obtain crude preparations and optimized the method using an orthogonal analysis. We obtained three polysaccharide fractions (EPPS-1, -2 and -3) using DEAE ion exchange and gel filtration chromatography. The homogeneity of the fractions was confirmed using high performance gel permeation chromatography. EPPS-3 administered to mice in a LPS-induced septicemia model effectively counteracted the effects of LPS resulting in significantly less lung damage. This trend was also seen in the serum and lung cytokine levels where EPPS-3 significantly decreased the levels of TNF-α and IL-6 and increased IL-10. Particularly, we fully characterized the structure of the EPPS-3 polysaccharide using a series of technologies. This polysaccharide structure was mainly composed of →4)-α-Glcp-(1→, →4)-α-Galp-(1→, T-α-Araf-(1→, →3,4)-β-GalpA-(1→ glycosidic linkages at a certain proportion. In sum, EPPS-3, with a clear structure, has potent anti-inflammatory activities and is a candidate for further development as an anti-inflammatory agent for clinical development.

Interaction of exopolysaccharide produced by Lactobacillus plantarum YW11 with whey proteins and functionalities of the polymer complex

Exopolysaccharide (EPS)-producing lactic acid bacteria have been widely used in fermented milk, but interaction between the EPS and milk proteins has not been well studied. In this study, interaction between the EPS from Lactobacillus plantarum YW11 (EPS-YW11) and whey proteins (WP), and functional properties of the EPS-YW11/WP were investigated. The results showed that EPS-YW11 tended to encase WP by ζ-potential analysis with a decrease in the surface charge of the protein fraction (from -26.00 mV to 15.30 mV), and an increase in the melting temperature of the protein fraction (from 76.31 °C to 84.48 °C) as shown by differential scanning calorimetry. Circular dichroism spectrometry showed that the EPS could induce structural change of WP, that is, increment in the content of α-helixes and random coils, There was stronger interaction between EPS-YW11 and WP at higher temperatures (60 °C, 90 °C) due to formation of intermolecular H-bonds and OH stretching vibration as indicated by infrared spectral analysis. A significant improvement in the texture (hardness, springiness, gumminess, resilience, cohesiveness, and chewiness) of the EPS-YW11/WP complex was also observed when compared to that of the EPS or WP alone. This was confirmed by microstructural observation of the EPS-YW11/WP complex that formed branched and porous structures, and it became more complex and stable with increased temperature treatment. Due to the strong interaction the EPS-YW11/WP exhibited improved functionality. This study identifies the potential of the EPS-YW11 to serve as a functional agent in the processing of fermented dairy products with enhanced textural stability and bioactivities such as cholesterol-lowering, antioxidant, and antibiofilm.

In vitro simulated digestion and fecal fermentation of polysaccharides from loquat leaves: Dynamic changes in physicochemical properties and impacts on human gut microbiota

The aim of this study was to well understand the dynamic changes of physicochemical properties of polysaccharides from loquat leaves (LLP) during in vitro simulated saliva-gastrointestinal digestion and fecal fermentation and its related impacts on human gut microbiota. Results showed that the contents of reducing sugar of LLP slightly increased during the gastrointestinal digestion, and its molecular weight also slightly decreased, suggesting that LLP could be slightly degraded under the gastrointestinal digestion conditions. Moreover, during the fecal fermentation, the molecular weight of the indigestible LLP (LLP-I) significantly decreased, and the molar ratio of constituent monosaccharides of LLP-I, such as glucuronic acid, galacturonic acid, galactose, and arabinose, significantly changed, indicating that LLP-I could be degraded and consumed by human gut microbiota. Indeed, some beneficial bacteria such as Megasphaera, Megamonas, Bifidobacterium, Phascolarctobacterium, and Desulfovibrio significantly increased, suggesting that LLP-I could change the composition and abundance of gut microbiota. LLP-I could also promote the production of health-promoting short chain fatty acids. Results from this study are benefical to well understand the in vitro digestion and fecal fermentation behaviors of LLP, and LLP can be developed as a potential prebiotic in the functional food industry.

Four sesquiterpene glycosides from loquat (Eriobotrya japonica) leaf ameliorates palmitic acid-induced insulin resistance and lipid accumulation in HepG2 Cells via AMPK signaling pathway

Insulin resistance (IR), caused by impaired insulin signal and decreased insulin sensitivity, is generally responsible for the pathophysiology of type 2 diabetes mellitus (T2DM). Sesquiterpene glycosides (SGs), the exclusive natural products from loquat leaf, have been regarded as potential lead compounds owing to their high efficacy in hypoglycemia and hypolipidemia. Here, we evaluated the beneficial effects of four single SGs isolated from loquat leaf, including SG1, SG2, SG3 and one novel compound SG4 against palmitic acid-induced insulin resistance in HepG2 cells. SG1, SG3 and SG4 could significantly enhance glucose uptake of insulin-resistant HepG2 cells at non-cytotoxic concentration. Meanwhile, Oil Red O staining showed the decrease of both total cholesterol and triglyceride content, suggesting the amelioration of lipid accumulation by SGs in insulin-resistant HepG2 cells. Further investigations found that the expression levels of phosphorylated AMPK, ACC, IRS-1, and Akt were significantly up-regulated after SGs treatment, on the contrary, the expression levels of SREBP-1 and FAS were significantly down-regulated. Notably, AMPK inhibitor Compound C (CC) blocked the regulative effects, while AMPK activator AICAR mimicked the effects of SGs in PA-treated insulin-resistant HepG2 cells. In conclusion, SGs (SG4>SG1≈SG3>SG2) improved lipid accumulation in insulin-resistant HepG2 cells through the AMPK signaling pathway.

Multiple fingerprint profiling for quality evaluation of polysaccharides and related biological activity analysis of Chinese patent drugs: Zishen Yutai Pills as a case study

ETHNOPHARMACOLOGICAL RELEVANCE

Zishen Yutai Pills (ZYP), a famous traditional Chinese patent medicine, has been widely applied to avoid recurrent miscarriage and treat threatened abortion. Polysaccharides of ZYP (ZYPPs) play an essential role in the theraprutic effects of ZYP. However, the complex compositions of ZYP and the complicated structure of ZYPPs have posed great challenges and barriers to the quality evaluation of ZYP.

AIM OF THE STUDY

To identify and characterize the ZYPPs for better quality control of ZYP, a reliable and valid quality control system was established in this study.

MATERIALS AND METHODS

A multi-fingerprint profile strategy based on HPSEC-MALL-RID, FT-IR, and HPLC (complete acid digested fingerprint, partial acid digested fingerprint and enzymatically digested fingerprint) was established to identify and discriminate the chemical structure of ZYPPs. Besides, the purpose of revealing the relationships between structure and biological activity of ZYPPs, their chemical characteristics, in vitro antioxidant and anti-glycation activities were investigated and discussed.

RESULTS

The similarity evaluation of ZYPPs indicated ZYPPs from different batches showed a high similarity based on the correlation coefficient values of multi-fingerprints. Furthermore, ZYPPs exhibited remarkable antioxidant and antiglycation properties, which might be attributed to their molecular weights and the content of uronic acids.

CONCLUSIONS

These results indicated that the multiple fingerprint technique was reliable and effective for the improvement of quality control of ZYPPs, suggesting the multiple fingerprint technique could also be potentially applied as a valid and feasible strategy to control the quality of polysaccharide-enriched herbal medicines.

Polyphenolic-Protein-Polysaccharide Complexes from Hovenia dulcis: Insights into Extraction Methods on Their Physicochemical Properties and In Vitro Bioactivities

Seven extraction methods, including hot water extraction (HWE), pressurized water extraction (PWE), ultrasound-assisted extraction, microwave-assisted extraction, ultrasound-assisted enzymatic extraction, high-speed shearing homogenization extraction, and ultrasound-microwave-assisted extraction, were utilized to extract polyphenolic-protein-polysaccharide complexes (PPPs) from Hovenia dulcis. Next, their physicochemical properties and in vitro antioxidant activities, antiglycation effects, and inhibition activities on α-glucosidase and α-amylase were studied and compared. The findings from this study indicate that various extraction processes exhibit notable influences on the physicochemical properties and in vitro bioactivities of PPPs. Extraction yields, contents of polyphenolics and flavonoids, apparent viscosities, molecular weights, molar ratios of monosaccharide compositions, and ratios of amino acid compositions in PPPs varied in different extraction methods. Furthermore, 13 phenolic compounds in PPPs, including rutin, myricitrin, myricetin, quercetin, kaempferol, protocatechuic acid, gallocatechin, p-hydroxybenzoic acid, ampelopsin, quercetin-7,4'-diglucoside, dihydroquercetin, 5-methylmyricetin, and naringenin, were identified. The relatively strong in vitro antioxidant activities, antiglycation effects, and inhibition activities on α-glucosidase and α-amylase were determined in both PPP-W and PPP-P obtained by HWE and PWE, respectively. The high content of total polyphenolics may be one of the main contributors to their in vitro bioactivities. The findings have shown that the PWE method can be an appropriate method to prepare PPPs with strong bioactivities for application in the functional food industry.

Effects of simulated saliva-gastrointestinal digestion on the physicochemical properties and bioactivities of okra polysaccharides

This study was to investigate the effects of in vitro simulated saliva-gastrointestinal digestion on the physicochemical properties and bioactivities of okra polysaccharides (OPS). Results showed that the digestibilities of OPS were about 5.1%, 37.5%, and 41.3% after saliva digestion (SD), saliva-gastric digestion (SGD), and saliva-gastrointestinal digestion (SGID), respectively. The SGID significantly changed the physicochemical properties of OPS, such as total uronic acids, total flavonoids, monosaccharide composition, rheological properties, and molecular weights (M_w). Especially, M_w changes resulted in the breakdown of glycosidic bonds during SGD, and the degradation of OPS during SGID was mainly caused by disrupting aggregates. Furthermore, the bioactivities of OPS were also affected by SGID. After SGID, OPS still possessed strong antioxidant activities, binding capacities, and prebiotic activities, but the α-glucosidase inhibitory effect was obviously decreased. Overall, results can provide valuable and scientific support on the oral administration of OPS as functional foods and medicines in the future.

Ultrasonic-Assisted Extraction, Structural Characterization, Chain Conformation, and Biological Activities of a Pectic-Polysaccharide from Okra (Abelmoschus esculentus)

The purpose of this study was to better understand the chemical characteristics and chain conformation of okra polysaccharides extracted by ultrasonic-assisted extraction. A pectic-polysaccharide, named OPP-D, was obtained, which was mainly composed of rhamnose, galacturonic acid, and galactose with a molar ratio of 1.01:1.00:2.31. Combined with NMR analysis, -4)-α-d-GalAp-(1,2,4)-α-l-Rhap-(1- were identified as the backbone with galactan side chains substituted partly at O-4 of Rhap. Molecular weight and radius of gyration of OPP-D were determined as 2.19 × 10⁵ Da and 27.0 nm, respectively. OPP-D was determined as an air-core sphere with branching chains in 0.9% NaCl solution by high-performance size-exclusion chromatography coupled with multi-angle laser light scattering and dynamic light scattering for the first time. Moreover, OPP-D exhibited typical shear-thinning behavior. In addition, OPP-D exhibited remarkable in vitro antioxidant activities and prebiotic activities, while the relatively high molecular weight, high degree of esterification, high content of uronic acids, and highly branched globular conformation of OPP-D might contribute to its in vitro anti-diabetic activities and binding capacities. Results can contribute to a better understanding of the structure–bioactivity relationship of OPPs, and OPP-D has great potential applications in the functional food and pharmaceutical industries.

Polysaccharides from loquat (Eriobotrya japonica) leaves: Impacts of extraction methods on their physicochemical characteristics and biological activities

Impacts of hot water extraction (HWE), pressurized water extraction (PWE), high-speed shearing homogenization extraction, microwave assisted extraction (MAE), ultrasound assisted extraction (UAE), ultrasound assisted enzymatic extraction, and ultrasound-microwave assisted extraction (UMAE) on physicochemical characteristics and bioactivities of polysaccharides from loquat (Eriobotrya japonica) leaves (LLPs) were investigated. Results showed that the degrees of esterification, contents of phenolics and uronic acids, constituent monosaccharides, apparent viscosities, and molecular weights of LLPs varied by different extraction methods. Bioactivities of LLPs were also significantly affected by different extraction methods. The high molecular weight and high degree of esterification of LLP-W and LLP-P extracted by HWE and PWE, respectively, might contribute to their strong binding capacities. The strong antioxidant activities and inhibitory effects on α-amylase and α-glucosidase were found in LLP-M and LLP-U extracted by MAE and UAE, respectively, which might be attributed to their contents of uronic acids, contents of total phenolics, and molecular weights. The low molecular weights and viscosities of LLP-U and LLP-UM extracted by UMAE might contribute to their strong prebiotic effects. These findings could provide scientific foundations for selecting appropriate extraction methods to obtain LLPs with desired bioactivities for applications in the pharmaceutical and functional food industries.

Comparison of structural characteristics and bioactivities of polysaccharides from loquat leaves prepared by different drying techniques

In the present study, freeze drying, hot-air drying, vacuum drying, and microwave drying at the microwave powers of 400, 600, and 800 W, respectively, were utilized to dry loquat leaves for evaluating the effects of different drying techniques on the physicochemical structures and bioactivities of polysaccharides extracted from loquat leaves (LLPs). Results demonstrated that the physicochemical structures and bioactivities of LLPs significantly affected by different drying techniques. The degrees of esterification, molar ratios of constituent monosaccharides, contents of uronic acids, apparent viscosities, and molecular weights of LLPs were varied by different drying techniques. Additionally, LLPs, particularly LLP-M4 which extracted from loquat leaves prepared by microwave drying at the power of 400 W, exerted remarkable in vitro binding capacities, strong inhibitory effects on α-amylase and α-glucosidase, and obvious antioxidant activities. Results indicated that the microwave drying could be an efficient drying technique before extraction of bioactive LLPs, and LLPs had great potential applications in the functional food and pharmaceutical industries.

Novel Antioxidant, Anti-α-Amylase, Anti-Inflammatory and Antinociceptive Water-Soluble Polysaccharides from the Aerial Part of Nitraria retusa

In this paper, water-soluble polysaccharides (named as NRLP) were extracted from Nitraria retusa leaves. The main structural features of NRLP were determined by High-pressure size exclusion chromatography, Fourier transform infrared and Gas Chromatography/Mass Spectrometry-Electronic Impact analysis. The in vitro and in vivo biological potential of NRLP were evaluated by measuring its antioxidant (•OH and DPPH• scavenging, total antioxidant capacity), anti-α-amylase as well as anti-inflammatory and antinociceptive activities in a mice model. NRLP was composed of Rha (33.7%), Gal (18.1%), GalA (15.0%), Glc (13.3%), Ara (13.3%), Xyl (3.8%), and GlcA (2.8%) and showed a Molecular Weight (Mw) of 23.0 kDa and a polydispersity index (PDI) of 1.66. The investigations highlighted a significant antioxidant activity (IC50 = 2.4-2.6 mg/mL) and an inhibition activity against α-amylase (IC50 = 4.55 mg/mL) in a dose-dependent manner. Further, NRLP revealed interesting anti-edematous effects and antinociceptive activities (both > 70%). These results open up new pharmacological prospects for the water-soluble polysaccharides extracted from Nitraria retusa leaves.

Effects of drying methods on the physicochemical characteristics and bioactivities of polyphenolic-protein-polysaccharide conjugates from Hovenia dulcis

Four drying methods, including freeze drying, hot air drying, vacuum drying, microwave drying at 400, 600, and 800 W, were applied to dry the peduncles of Hovenia dulcis. Then the effects of different drying methods on physicochemical characteristics and bioactivities of polyphenolic-protein-polysaccharides conjugates extracted from H. dulcis (PPPs) were investigated and compared. Results showed that different drying methods affected the physicochemical characteristics and bioactivities of PPPs. Noticeable variations in extraction yields, contents of total proteins, contents of total polyphenolics, contents of total flavonoids, contents of uronic acids, molecular weights, apparent viscosities, molar ratios of constituent monosaccharides, ratios of constituent amino acids, and degrees of esterification were observed in PPPs obtained by different drying methods. Besides, a total of 13 phenolic compounds in PPPs were identified by UPLC-ESI-QTOF-MS. In addition, PPPs, especially PPP-M6 and PPP-V dried by microwave drying at 600 W and vacuum drying, respectively, exhibited remarkable antioxidant activities, antiglycation activities, and inhibitory activities on α-amylase and α-glucosidase. Results suggested that the microwave drying and vacuum drying techniques could be appropriate drying methods before extraction of PPPs with high bioactivities for applications in the functional food and medicine industries.