Isolation and structural characterization of a non-competitive α-glucosidase inhibitory polysaccharide from the seeds of Litchi chinensis Sonn

The ultrasonic-assisted enzymatic extraction, characteristics and antioxidant activities of lychee nuclear polysaccharide

A response surface methodology (RSM) and one-factor method were established to investigate the optimum conditions for the extraction of lychee nuclear polysaccharides (LSP) by ultrasonic-assisted pectinase. The content of basic components in polysaccharides was determined. The antioxidant activity was well determined and compared the differences in the activities of the polysaccharides extracted by water extraction (LSP-HW) and those extracted at ultrasound-assisted enzyme (LSP-UAE). The activity of lychee nuclear polysaccharide increased with the increase of concentration. The anti-hydroxyl radical and anti-lipid peroxidation abilities of lychee nuclear polysaccharide were more excellent, and LSP-HW was slightly better than LSP-UAE in terms of activity, but the difference was not significant. In terms of solubility; LSP-HW without deproteinization was the best, followed by LSP-UAE, and the worst was LSP-UAE after deproteinization. The higher the glycoprotein content, the better the solubility of its polysaccharide. Compared with the existing extraction methods, this experiment greatly improved the extraction rate of lychee nuclear polysaccharides and further enriched the antioxidant activities of polysaccharides.

Antibacterial activity of a polysaccharide isolated from litchi (Litchi chinensis Sonn.) pericarp against Staphylococcus aureus and the mechanism investigation

The long-term use of antibiotics can cause drug resistance. Natural polysaccharides are a novel means of treating bacterial infections, and the development and utilization of litchi pericarp polysaccharide (LPPs) as a bacteriostatic active substance offer a new research direction for the high-value utilization of litchi by-products. This study revealed that LPPs inhibited Staphylococcus aureus more than Escherichia coli, Listeria monocytogenes, and Salmonella typhimurium, with the minimum inhibitory concentrations of 145, 205, 325, and 445 μg/mL, respectively. The inhibitory activity of LPPs was insignificant for Bacillus subtilis at 505 μg/mL. The assessment of antibacterial mechanisms revealed that LPPs influenced the growth, conductivity, protein, and nucleic acid, reducing sugar, respiratory chain dehydrogenase activity, bacterial lipid peroxidation, intracellular adenosine triphosphate, and extracellular alkaline phosphatase levels of S. aureus. Of note, LPPs could modify the cell wall integrity and cell membrane permeability of S. aureus, resulting in the leakage of intracellular large and small molecules, inhibition of cellular respiratory metabolism, and oxidative losses. These processes exhibited an inhibitory effect and made the bacterium nonfunctional, thereby affecting its growth and metabolism or causing cell death. These findings provide support and insights into the potential application of LPPs as a natural antimicrobial agent.

Evaluation of cosmetic efficacy of lychee seed fermentation liquid

BACKGROUND

Lychee seeds were fermented by three kinds of bacteria (Lactobacillus plantarum, Saccharomyces cerevillus and ganoderma lucidum mycelium), and two effective strains were selected by two indexes of activity content and antioxidant, so as to further verify whether lychee seeds have waste multiplication effect and can protect cells damaged by oxidation from anti-inflammatory, anti-aging and safety.

RESULTS

The contents of polyphenols, flavonoids and proteins in the solution fermented by Ganoderma lucidum mycelium did not increase, thus affecting the antioxidant capacity of the solution was far less than that of the water extract. The active content of the other two fermentation solutions was higher than that of the water extract, and the ability of scavenging free radicals of the two solutions increased with the increase of the volume fraction. At the cellular level, the two fermentation solutions showed repair effects on UVA-induced damaged cells. The contents of type I collagen (COL-1), total antioxidant capacity and ELN were increased, the contents of reactive oxygen species and MDA were decreased, and the expressions of inflammatory factors IL-6, TNF-a, iNOS and COX-2 were decreased in HaCaT cells. From the gene level, the mRNA contents of IL-6, TNF-a, Caspase-3, Caspase-9, Bax and Bcl were significantly decreased. The test of chick embryo chorioallantoic membrane (HTET CAM) showed that there was no bleeding and litchi seed fermentation liquid was not irritating.

CONCLUSIONS

Therefore, two kinds of litchi seed fermentation can be used as natural plant raw materials for cosmetics, and have strong antioxidant, anti-inflammatory and anti-aging functions on skin, and also have good human safety.

Non-covalent binding of chlorogenic acid to myofibrillar protein improved its bio-functionality properties and metabolic fate

As natural antioxidants added to meat products, polyphenols can interact with proteins, and the acid-base environment influenced the extent of non-covalent and covalent interactions between them. This study compared the bio-functional characteristics and metabolic outcomes of the myofibrillar protein-chlorogenic acid (MP-CGA) complexes binding in different environments (pH 6.0 and 8.5). The results showed that CGA bound with MP significantly enhanced its antioxidant activity and inhibitory effect on metabolism enzymes. CGA bound deeply into the MP structure hydrophobic cavity at pH 6.0, which reduced its degradation by digestive enzymes, thus increasing its bio-accessibility from 59.5% to 71.6%. The digestion products of the two complexes exhibited significant differences, with the non-covalent MP-CGA complexes formed at pH 6.0 showing significantly higher concentrations of rhetsinine and piplartine, two well-known compounds to modulate diabetes. This study demonstrated that non-covalent binding between protein and polyphenol in the acidic environment held greater promising prospects for improving health.

Effects and mechanism of extracts rich in phenylpropanoids-polyacetylenes and polysaccharides from Codonopsis Radix on improving scopolamine-induced memory impairment of mice

ETHNOPHARMACOLOGICAL RELEVANCE

Alzheimer's disease (AD) is a progressive developmental neurodegenerative disease that primarily develops in old age. Memory impairment is an important manifestation of AD. It has been demonstrated that inflammation and oxidative stress are important mediators in the development and progression of AD. Codonopsis Radix (CR) has a long history of consumption, exhibiting lots of beneficial health effects, including anti-ageing, antioxidant, and anti-inflammatory properties. However, studies on the effects of CR on scopolamine-induced amnesia have rarely been reported.

AIM OF THE STUDY

The aim of this study was to investigate the ameliorative effect of macromolecular portion (polysaccharides, POL) and small molecule portion (fine extract rich in phenylpropanoids-polyacetylenes, EPP) from CR on improving scopolamine-induced memory impairment and to elucidate the potential mechanism of action.

MATERIALS AND METHODS

C57BL/6 mice were pretreated with EPP (0.2, 0.4, and 0.6 g/kg), POL (0.3, 0.6, and 0.9 g/kg), and donepezil (5 mg/kg) by gavage for 7 days, followed by intraperitoneal injection of scopolamine (1 mg/kg) to induce memory impairment. The 16S rRNA gene sequencing, histopathological, western blotting, and biochemical analysis (various biochemical markers and protein expressions related to cholinergic system, oxidative stress, and neuroinflammation) were performed to further elucidate the mechanism of action. Moreover, the acetylcholinesterase (AChE) inhibitory activities of POL, EPP, and its main compounds tangshenoside I, lobetyol, lobetyolin, and lobetyolinin were evaluated.

RESULTS

Experiments have confirmed that both POL and EPP from CR could improve scopolamine-induced spatial learning memory deficits. Both of them could regulate cholinergic function by inhibiting AChE and activating choline acetyltransferase (ChAT) activities. They also could enhance antioxidant defense via increasing the activities of superoxide dismutase and glutathione peroxidase, and anti-inflammatory function through suppressing inflammatory factors (nitric oxide, TNF-α, and IL-6) and regulating gut flora. Besides, in vitro experiments demonstrated that four monomeric compounds and EPP, except POL, exhibited inhibition of AChE activity.

CONCLUSION

EPP and POL from CR exert a beneficial effect on learning and memory processes in mice with scopolamine-induced memory impairment. CR may be a promising medicine for preventing and improving learning memory.

Gastrointestinal digestion assays for evaluating the bioaccessibility of phenolic compounds in fruits and their derivates: an overview

Fruits and their derivatives are sources of phenolic compounds, which contribute to the maintenance of health benefits. In order to exert such properties, these compounds must be exposed to gastrointestinal conditions during digestion. In vitro methods of gastrointestinal digestion have been developed to simulate and evaluate the changes that compounds undergo after being exposed to various conditions. We present, in this review, the major in vitro methods for evaluating the effects of gastrointestinal digestion of phenolic compounds in fruits and their derivatives. We discuss the concept of bioaccessibility, bioactivity, and bioavailability, as well as the conceptual differences and calculations among studies. Finally, the main changes caused by in vitro gastrointestinal digestion in phenolic compounds are also discussed. The significant variation of parameters and concepts observed hinders a better evaluation of the real effects on the antioxidant activity of phenolic compounds, thus, the use of standardized methods in research would contribute for a better understanding of these changes.

Beyond cellulose: pharmaceutical potential for bioactive plant polysaccharides in treating disease and gut dysbiosis

Polysaccharides derived from plants, algae, or fungi serve as the major components of some human diets. Polysaccharides have been shown to exhibit diverse biological activities in improving human health, and have also been proposed to function as potent modulators of gut microbiota composition, thus playing a bi-directional regulatory role in host health. Here, we review a variety of polysaccharide structures potentially linked to biological functions, and cover current research progress in characterizing their pharmaceutical effects in various disease models, including antioxidant, anticoagulant, anti-inflammatory, immunomodulatory, hypoglycemic, and antimicrobial activities. We also highlight the effects of polysaccharides on modulating gut microbiota via enrichment for beneficial taxa and suppression of potential pathogens, leading to increased microbial expression of carbohydrate-active enzymes and enhanced short chain fatty acid production. This review also discusses polysaccharide-mediated improvements in gut function by influencing interleukin and hormone secretion in host intestinal epithelial cells.

Artificial neural network model- and response surface methodology-based optimization of Atractylodis Macrocephalae Rhizoma polysaccharide extraction, kinetic modelling and structural characterization

Atractylodis Macrocephalae Rhizoma (AMR) is the dried rhizome of Atractylodes macrocephala Koidz, which is widely used in the development of health products. AMR contains a large number of polysaccharides, but at present there are fewer applications for these polysaccharides. In this study, the effects of different extraction methods on the Atractylodis Macrocephalae Rhizoma polysaccharide (AMRP) yield were investigated, and the conditions for ultrasound-assisted extraction were optimized by response surface methodology (RSM) and three neural network models (BP neural network, GA-BP neural network and ACO-GA-BP neural network). The best conditions were a liquid-to-solid ratio of 17 mL/g, ultrasonic power of 400 W, extraction temperature of 72 °C, and extraction time of 40 min, which yielded 31.31% AMRP. The kinetic equation of AMRP was determined and compared with the results predicted by three neural network models. It was finally determined that the extraction conditions, kinetic processes and kinetic equation predicted by the GA-ACO-BP neural network were optimal. In addition, AMRP was characterized using SEM, FTIR, HPLC, UV, XRD, and NMR, and the structural study revealed that AMRP has a rough exterior and a porous interior; moreover, it contains high levels of glucose (5.07%), arabinose (0.80%), and galactose (0.74%). AMRP has three crystal structures, consisting of two β-type monosaccharides and one α-type monosaccharide. Additionally, the effectiveness of AMRP as an antioxidant was demonstrated in an in vitro experiment.

Structural characterization and anti-osteoporosis effect of an arabinomannan from Anemarrhena asphodeloides Bge

To discover the polysaccharide with anti-diabetic osteoporosis (DOP) activity and clarify its structure, an arabinomannan (PAAP-1B) with a molecular weight of 14.0 kDa was isolated from Anemarrhena asphodeloides Bge. using column chromatography. It consists of arabinose, mannose, and galactose in a molar ratio of 6:3:1. PAAP-1B has a backbone composed of 1,5-α-Araf, 1,4-β-Manp, and 1,6-β-Galp residues that are branched at C3 of α-Araf and β-Galp residues. The side chains are T-α-Araf, T-α-Manp, T-β-Galp, and 1,6-β-Galp. PAAP-1B attenuated DOP and reduced ferroptosis in the femurs and tibias of alloxan-induced mice. It also suppressed ferroptosis in advanced glycation end product-induced osteoblasts by decreasing 4-hydroxynonenal, malondialdehyde, mitochondrial reactive oxidative species levels, and lipid peroxidation, while reversing the downregulation of solute carrier family 7 membrane 11 and glutathione expression.

Optimization and Molecular Mechanism of Novel α-Glucosidase Inhibitory Peptides Derived from Camellia Seed Cake through Enzymatic Hydrolysis

In recent years, food-derived hypoglycemic peptides have received a lot of attention in the study of active peptides, but their anti-diabetic mechanism of action is not yet clear. In this study, camellia seed cake protein (CSCP) was used to prepare active peptides with α-glucosidase inhibition. The optimization of the preparation of camellia seed cake protein hydrolyzed peptides (CSCPH) was conducted via response surface methodology (RSM) using a protamex with α-glucosidase inhibition as an indicator. The optimal hydrolysis conditions were pH 7.11, 4300 U/g enzyme concentration, 50 °C hydrolysis temperature, and 3.95 h hydrolysis time. Under these conditions, the α-glucosidase inhibition rate of CSCPH was 58.70% (IC₅₀ 8.442 ± 0.33 mg/mL). The peptides with high α-glucosidase inhibitory activity were isolated from CSCPH by ultrafiltration and Sephadex G25. Leu-Leu-Val-Leu-Tyr-Tyr-Glu-Tyr (LLVLYYEY) and Leu-Leu-Leu-Leu-Pro-Ser-Tyr-Ser-Glu-Phe (LLLLPSYSEF) were identified and synthesized for the first time by Liquid chromatography electrospray ionisation tandem mass spectrometry (LC-ESI-MS/MS) analysis and virtual screening with IC₅₀ values of 0.33 and 1.11 mM, respectively. Lineweaver-Burk analysis and molecular docking demonstrated that LLVLYYEY was a non-competitive inhibitor of α-glucosidase, whereas LLLLPSYSEF inhibited α-glucosidase, which displayed a mixed inhibition mechanism. The study suggests the possibility of using peptides from Camellia seed cake as hypoglycaemic compounds for the prevention and treatment of diabetes.

Removing the sporoderm from the sporoderm-broken spores of Ganoderma lucidum improves the anticancer and immune-regulatory activity of the water-soluble polysaccharide

Plant-derived polysaccharides have demonstrated promising anti-cancer effects via immune-regulatory activity. The aim of the current study was to compare the chemical property and the anticancer effects of polysaccharides extracted from the sporoderm-removed spores of the medicinal mushroom Ganoderma lucidum (RSGLP), which removed the sporoderm completely, with polysaccharides extracted from the sporoderm-broken spores of G. lucidum (BSGLP). We found that RSGLP has a higher extraction yield than BSGLP. HPGPC and GC-MS results revealed that both RSGLP and BSGLP are heteropolysaccharides, but RSGLP had a higher molecular weight and a different ratio of monosaccharide composition than BSGLP. MTT and flow cytometry results demonstrated that RSGLP exhibited much higher dose-efficacy in inhibiting cell viability and inducing apoptosis than BSGLP in 8 cancer cell lines representing colon (HCT116 and HT29), liver (HepG2 and Huh-7), breast (MDA-MB-231 and MCF-7), and lung cancers (NCI-H460 and A549). Furthermore, RSGLP is more effective in inhibiting HCT116 and NCI-H460 xenograft tumor growth and inhibiting tumor-induced splenomegaly than BSGLP in nude mice, suggesting a better effect on regulating immunity of RSGLP. Next, we found that RSGLP is more potent in inhibiting the level of serum inflammatory cytokines in nude mice, and in inhibiting the activation of macrophage RAW264.7 and the expression of the inflammatory mediators IL-1β, TNF-α, iNOS, and COX-2 in vitro. This is the first study to compare the chemical properties, anti-cancer, and immune-regulatory effects of RSGLP and BSGLP using multiple cancer cell lines. Our results revealed that the sporoderm-removed spores of G. lucidum (RSGL) and RSGLP may serve as new anticancer agents for their promising immune-regulatory activity.

Blue honeysuckle extracts retarded starch digestion by inhibiting glycosidases and changing the starch structure

Blue honeysuckle rich in anthocyanins can inhibit starch-digesting enzyme activity. This study evaluated the inhibitory effect and mechanism of blue honeysuckle extract (BHE) on glycosidases (α-amylase and α-glucosidase). BHE was a mixed glycosidase inhibitor with an IC₅₀ of 2.36 ± 0.14 and 0.06 ± 0.01 for α-amylase and α-glucosidase, respectively. Fourier transform infrared (FTIR) spectroscopy, multi-fluorescence spectroscopy, and isothermal titration calorimetry (ITC) confirmed that BHE caused the secondary structure change and static fluorescence quenching of glycosidases, and the interaction was an enthalpy-driven exothermic reaction. Molecular docking proved that the main anthocyanin monomers in BHE interacted with glycosidases through hydrogen bonds and van der Waals forces. Moreover, BHE changed the starch structure and prevented starch from being digested by glycosidases. In vivo, BHE and starch-BHE complexes effectively slowed postprandial hyperglycemia. This research provided a theoretical basis for BHE in antidiabetic healthy food research and development.

Structural characterization of a novel polysaccharide from sweet corncob that inhibits glycosylase in STZ-induced diabetic rats : Structural characterization of a novel polysaccharide

In the current study, we extracted a polysaccharide from sweet corncob and evaluated its hypoglycemic function. After collection in water, alcohol precipitation, and purification by DEAE-52 and Sephadex G-100 columns, we obtained a polysaccharide (SCP50) that was composed primarily of mannose and glucose (9.73:190.27), with a molecular weight of 9280.33 Da. We demonstrated that SCP50 exhibited significant inhibition of α-glucosidase activity, with an IC50 of 4.866 mg/mL, K_m of 1.297 × 10^-3, and V_max of 0.076 mol/L·min^-1 in vitro. We also observed that SCP50 markedly attenuated disaccharidase (maltase, sucrase, and lactase) activity in a rat model of T2DM. We conclude that SCP50 exerts a hypoglycemic effect via inhibition of intestinal glycosylase. These results thus provide new insight into the hypoglycemic action underlying sweet corncob polysaccharide's effects.

Novel pectin-like polysaccharide from Panax notoginseng attenuates renal tubular cells fibrogenesis induced by TGF-β

Renal fibrosis is the final common result of a variety of progressive injuries leading to chronic renal failure. However, there are no effective clinical available drugs for the treatment. Notoginsenoside from Panax notoginseng could ameliorate renal fibrosis. We hypothesized that polysaccharide from this herb might have similar bioactivity. Here, we elucidated structure of a novel pectin-like polysaccharide designed SQD4S2 with a netty antenna backbone of glucogalacturonan substituted by glucoarabinan, glucurogalactan and galactose residues from this herb. Interestingly, SQD4S2 could reverse the morphological changes of human renal tubular HK-2 cells induced by TGF-β. Mechanism study suggested that this bioactivity might associate with N-cadherin (CDH2), Snail (SNAI1), Slug (SNAI2) depression and E-cadherin (CDH1) enhancement. In addition, SQD4S2 could impede critical fibrogenesis associated molecules such as α-SMA, fibronectin, vimentin, COL1A1, COL3A1, FN1 and ACTA2 expression induced by TGF-β in HK-2 cells. Current findings outline a novel leading polysaccharide for against renal fibrosis new drug development.

Chemical Characterization and Evaluation of the Antihyperglycemic Effect of Lychee (Litchi chinensis Sonn.) cv. Brewster

Lychee is a fruit of Asian origin with an exquisite flavor and an attractive reddish color. However, according to recent reports, the consumption of this fruit reduces the levels of blood glucose with adverse effects on human health such as encephalopathy and hypoglycemic. The objective of this work was to determine if the peel, pulp, and seed of "Brewster" lychee fruits harvested at two stages of maturity had antihyperglycemic effect. This effect was determined by an oral glucose tolerance test using Wistar rats. In addition, ultraviolet-visible spectrophotometry and high-resolution liquid chromatography were used to quantify phenolic compounds, flavonoids, organic acids (OAs), sugars, and antioxidant activity. Results indicated that stage I pulp (immature fruits) and stage II peel and seed (export mature fruits) reduced blood glucose levels, and the effects of the former two were synergistic with metformin. The pulp of mature fruits (stage II), however, lacked a hypoglycemic effect. Additionally, the peel and the seeds of these fruits presented a high antioxidant activity (as determined by DPPH [2,2-diphenyl-2-picryl-hydracyl] and ABTS⁺ [2,2-azino-bis-(3-ethylbenzothiazoline)-6-sulfonic acid] methods), which correlated well with the total content of phenolic compounds. The highest content of polyphenolics, flavonoids, and OAs was found in the extracts of the peel and seeds of both stages of maturity. It was therefore concluded that "Brewster" mature lychees are safe for human consumption, and both the seed and the peel can be useful sources for obtaining new compounds with antihyperglycemic activity.

A review on the medicinal potential, toxicology, and phytochemistry of litchi fruit peel and seed

The perception that many fruit wastes, particularly the peel, contain more phytochemicals than the edible portions has been largely supported by scientific evidence, making them potential sources of bioactive and therapeutic phytochemicals. The peel and seed of Litchi (Litchi chinensis Sonn.) contain bioactive principles and have been shown to exhibit antioxidative, antidiabetic, cancer preventive, anti-obesogenic, and anti-inflammatory properties. This review presents a critical analysis of previous and current perspectives on the medicinal, toxicological, and phytochemical profiles of litchi fruit peel and seed, thus providing an evidence-based platform to explore their medicinal potential. A literature search was done on "PubMed," "Google Scholar," and "ScienceDirect." Peer-reviewed published data on the medicinal profiles of litchi fruit peel and seed were identified and critically analyzed. The fruit peel and seed improved glycemic control and insulin signaling and downregulated lipogenic and cholesterogenic processes. Their neuroprotective, hepatoprotective, and renal protective potentials were influenced by antioxidative and anti-inflammatory actions. The anticancer effect was mediated by upregulated proapoptotic, proinflammatory, antiproliferative, and anti-metastatic processes in cancer cells. Simple flavonols, sesquiterpenes, phenolic acids, jasmonates, and proathocyanidins are the possible bioactive principles influencing the medicinal effects. Appropriate toxicity studies are, however, still lacking. Litchi fruit wastes may be further studied as useful sources of therapeutic agents that may have medicinal relevance in oxidative, metabolic, vascular, and carcinogenic ailments. PRACTICAL APPLICATIONS: Underutilized fruit wastes contribute to environmental pollution. Interestingly, these wastes contain phytochemicals that could be of medicinal relevance if their medicinal potentials are maximized. Litchi fruit is a widely consumed fruit with commercial value. Its peel and seeds contribute to fruit wastes. The review exposes the medicinal potential and bioactive principles and/or nutrients of the fruit's peel and seed while elucidating the underlying therapeutic mechanisms or modes of actions through which litchi peel and seed potentiate medicinal effects. Thus, the review provides an evidence-based platform to explore the medicinal potential of underutilized wastes from litchi fruit. Additionally, the fruit peel and seed could be low-cost residues that could afford ecofriendly opportunity if their medicinal potentials are properly maximized.

Lychee Seed as a Potential Hypoglycemic Agent, and Exploration of its Underlying Mechanisms

Food is people's primal want. A reasonable diet and healthy food not only provide nutrients for human growth but also contribute to disease prevention and treatment, while following an unhealthy diet can lead to an increased risk of many diseases, especially metabolic disorders, such as diabetes. Nature is enriched with different food sources, and it seems that purely natural products are more in line with the current concept of health, which enhance the formation of the notion that "Food/Diet Supplements from Natural Sources as a Medicine." As a delicious fruit, the medicinal values such as anticancer, antibacterial, antioxidation, and antiglycating properties of lychee have been found. Lychee (Litchi in Chinese) is a subtropical fruit plant belonging to the family Sapindaceae. It has been widely cultivated in warm climates worldwide, particularly in China, for thousands of years. In recent years, various phytochemical components such as quercetin, procyanidin A2, and (2R)-naringenin-7-O-(3-O-αL-rhamnopyranosyl-β-D-glucopyranoside) have been identified in a lychee seed, which may lend a lychee seed as a relatively safe and inexpensive adjuvant treatment for diabetes and diabetic complications. In fact, accumulating evidence has shown that lychee seed, lychee seed extracts, and related compounds have promising antihyperglycemic activities, including improving insulin resistance, anti-inflammatory effect, lipid regulation, neuroprotection, antineurotoxic effect, and renoprotection effect. In this review, we summarized publications on antiglycemic effects and mechanisms of lychee seed, lychee seed extracts, and related compounds, which included their efficacies as a cure for diabetes and diabetic complications in cells, animals, and humans, attempting to obtain a robust evidence basis for the clinical application and value of lychee seed.

Antifatigue and antihypoxia activities of oligosaccharides and polysaccharides from Codonopsis pilosula in mice

Codonopsis pilosula is a traditional Chinese medicine and food supplement that is widely used in China. This study aimed to investigate the antifatigue and antihypoxia activities of different extracts and fractions from C. pilosula, including ethanol extract (ETH), water extract (WAT), polysaccharides (POL), inulin (INU) and oligosaccharides (OLI). Different extracts and fractions were orally administered to mice at the doses of 0.25, 0.5 and 1.0 g kg-1 once a day for 21 days. Antifatigue activity was assessed through the weight-loaded swimming test on the 21st day, and antihypoxia activity was evaluated through the normobarie hypoxia test on the following day. Finally, biochemical parameters, such as liver glycogen (LG), muscle glycogen (MG), blood urea nitrogen (BUN), lactic dehydrogenase (LDH), malondialdehyde (MDA), and glutathione (GSH) levels, were determined. The results showed that, compared with the control treatment, only POL treatment significantly prolonged the swimming time of the mice. POL groups had the strongest hypoxia tolerance, followed by the OLI and WAT groups. The levels of LG and MG were significantly increased by treatment with POL at the doses of 0.5 and 1.0 g kg-1, whereas BUN and LDH levels in POL groups were significantly lower than those in the control group. MDA under POL and OLI treatment was significantly lower than that under the control treatment. In addition, treatments with POL and OLI, except for treatment with a low dose of OLI, significantly increased GSH levels. In conclusion, POL could efficiently enhance antifatigue and antihypoxia abilities by increasing energy resources, decreasing detrimental metabolite accumulation, and enhancing antioxidant activity. OLI could improve antihypoxia activity by preventing lipid peroxidation and enhancing antioxidant activity.

Structural characteristics and in vitro and in vivo immunoregulatory properties of a gluco-arabinan from Angelica dahurica

A water-soluble polysaccharide identified here as ADP80-2 was acquired from Angelica dahurica. ADP80-2 was a gluco-arabinan composed of arabinose and a trace of glucose with a molecular weight of 9950 g/mol. The backbone of ADP80-2 comprised →5)-α-L-Araf-(1→, →3, 5)-α-L-Araf-(1→, →6)-α-D-Glcp-(1→, with a terminal branch α-L-Araf-(1 → residue. In terms of immunoregulatory activity, ADP80-2 can significantly promote the phagocytosis, the production of nitric oxide (NO), and the secretion of cytokines (IL-6, IL-1β, and TNF-α) of macrophage. In addition to the cellular immunomodulatory activities, the chemokines related to immunoregulation were significantly increased in the zebrafish model after treated with ADP80-2. These biological results indicated that ADP80-2 with immunomodulatory effects was expected to be useful for the development of new immunomodulatory agents. Simultaneously, the discovery of ADP80-2 further revealed the chemical composition of A. dahurica used as a traditional Chinese medicine and spice.

Identification of curcumin as a potential α-glucosidase and dipeptidyl-peptidase 4 inhibitor: Molecular docking study, in vitro and in vivo biological evaluation

Natural compounds have tremendous potential to regulate glucose metabolism, but conventional methods for studying their bioactivities are usually labor intensive. Here, hypoglycemic properties in 22 selected food-derived compounds were examined using molecular docking. The results indicated that curcumin is an inhibitor of both α-glucosidase and dipeptidyl-peptidase 4 (DPP-4), which are important for glycemic control. These effects of curcumin were also confirmed by enzymatic determination in vitro. Furthermore, curcumin significantly improved diet-induced hyperglycemia (e.g., fasting plasma glucose levels and glycogen storage in muscle or liver) in mice. This might be attributed to its inhibitory effects on the activities of α-glucosidase and DPP-4 in vivo. Curcumin also upregulated the expression of genes (e.g., glucagon-like peptide 1) related to DPP-4 activity in the small intestine. In conclusion, curcumin is a potential ingredient of functional foods used for diet-induced hyperglycemia management. PRACTICAL APPLICATIONS: Curcumin has been widely used as a colorant in the food industry. Moreover, a growing number of studies have described its diverse biological functions, such as anti-inflammatory, anti-oxidant, and anti-angiogenic activities. Thus, curcumin is regarded as a potential ingredient in functional foods. Our results highlighted the hyperglycemic effect of curcumin, suggesting that curcumin may be included in food products for hyperglycemic patients.

Isolation and Purification of Polysaccharides from Litchi Seeds, with an Analysis of in Vitro Hypoglycemic Effect

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

Molecular mechanisms of bioactive polysaccharides from Ganoderma lucidum (Lingzhi), a review

Ganoderma lucidum, commonly known as "Lingzhi" in Chinese, are well-known medicinal mushrooms. Lingzhi has been used in traditional Chinese herbal medicines for more than two thousand years. G. lucidum polysaccharides (GLPs) are present at high levels in G. lucidum cells and GLPs have molecular weights ranging from thousands to millions. GLPs have been widely studied for their various biological activities, such as antioxidant, antitumor, anti-inflammatory, antiviral, anti-diabetes, and immunomodulatory activities. The methods for GLPs extraction and characterization are mature, but the comprehensive research on the relationship between GLPs structure (i.e., molecular weight, tertiary structure, branching, substituents, and monosaccharide composition) and function is still quite limited. The aim of this review is to update and summarize the mechanisms of the various bioactive polysaccharides extracted from G. lucidum. The information presented on these bio-mechanisms should be valuable in the research and development of GLPs-derived therapeutics.