Structure and antitumor and immunomodulatory activities of a water-soluble polysaccharide from Dimocarpus longan pulp

Comparison of different longan polysaccharides during gut Bacteroides fermentation

The bioactivity of polysaccharide was closely related to its fermentation utilization by gut Bacteroides, and its utilization degree was determined by various gut Bacteroides species and different polysaccharides characteristics. The effects of longan polysaccharide (LP) and LP treated by ultrasonic-assisted hydrogen peroxide for 8 h (DLP-8) on gut Bacteroides growth, and their fermentation utilization were compared. The results of LP and DLP-8 on the proliferation of six Bacteroides species showed that Bacteroides uniformis had the highest proliferation index. In fermentation by B. uniformis, DLP-8 (with a lower molecular weight), the viable count of which was higher than that of LP, was degraded more and especially utilized more glucose and glucuronic acid. The microstructure of the two polysaccharides changed differently during fermentation. Moreover, DLP-8 promoted greater short-chain fatty acids production than LP. These results indicated that the fermentation properties of DLP-8 by B. uniformis were superior to those of LP.

Potential of longan (Dimocarpus longan Lour.) in functional food: A review of molecular mechanism-directing health benefit properties

Longan (Dimocarpus longan Lour.) has received widespread attention worldwide as a therapeutic food with nutritional, economic, and medicinal value. Its fruit, seed, pericarp, and flower becoming dietary tools for health maintenance when it comes to targeting chronic diseases or sub-health conditions. In recent years, research focusing on longan and human health has intensified, and the high-value products of the whole fruit, including polyphenols, polysaccharides, angiotensin-I-converting enzyme (ACE)-inhibiting peptides, gamma-aminobutyric acid (GABA), and Maillard reaction products etc., may have beneficial effects on human health by preventing the onset of chronic diseases and cancer, maintaining intestinal homeostasis and skin health. Here, we review and summarize the new available evidence on the bioactive role of phytochemicals in longan and explore the relationship between longan bioactive compounds and health benefits, with a focus on the molecular mechanisms of the health effects.

Prevention of Hypercholesterolemia with "Liposomes in Microspheres" Composite Carriers: A Promising Approach for Intestinal-Targeted Oral Delivery of Astaxanthin

Cardiovascular diseases are caused by hypercholesterolemia. Astaxanthin (AST) has been reported to exhibit antioxidant and anti-inflammatory properties. However, its bioavailability is poor because of low solubility and instability. In order to improve the bioavailability of AST, we developed an intestinal-responsive composite carrier termed as "liposomes in micropheres" incorporating N-succinyl-chitosan (NSC)-poly(ethylene glycol) (PEG) liposomes that functionalized by neonatal Fc receptors (FcRn) into hydrogels of sodium alginate (SA) and carboxymethyl chitosan (CMCS). In the AST NSC/HSA-PEG liposomes@SA/CMCS microspheres, the AST's encapsulation efficiency (EE) was 96.26% (w/w) and its loading capacity (LC) was 6.47% (w/w). AST NSC/HSA-PEG liposomes had stability in the gastric conditions and achieved long-term release of AST in intestinal conditions. Then, AST NSC/HSA-PEG liposomes@SA/CMCS bind to intestinal epithelial cell targets by the neonatal Fc receptor. In vitro permeation studies show that there was a 4-fold increase of AST NSC/HSA-PEG liposomes@SA/CMCS in AST permeation across the intestinal epithelium. Subsequent in vivo experiments demonstrated that the composite carrier exhibited a remarkable mucoadhesive capacity, allowing for extended intestinal retention of up to 12 h, and it displayed deep penetration through the mucus layer, efficiently entering the intestinal villi epithelial cells, and enhancing the absorption of AST and its bioavailability in vivo. And oral administration of AST NSC/HSA-PEG liposomes@SA/CMCS could effectively prevent hypercholesterolemia caused by a high-fat, high-cholesterol diet (HFHCD). These advancements highlight the potential of NSC/HSA-PEG liposomes@SA/CMCS composite carriers for targeted and oral uptake of hydrophobic bioactives.

Research Progress on the Anticancer Activity of Plant Polysaccharides

Tumor is a serious threat to human health, with extremely high morbidity and mortality rates. However, tumor treatment is challenging, and the development of antitumor drugs has always been a significant research focus. Plant polysaccharides are known to possess various biological activities. They have many pharmacological properties such as immunomodulation, antitumor, antiviral, antioxidative, antithrombotic, and antiradiation effects, reduction of blood pressure and blood sugar levels, and protection from liver injury. Among these effects, the antitumor effect of plant polysaccharides has been widely studied. Plant polysaccharides can inhibit tumor proliferation and growth by inhibiting tumor cell invasion and metastasis, inducing cell apoptosis, affecting the cell cycle, and regulating the tumor microenvironment. They also have the characteristics of safety, high efficiency, and low toxicity, which can alleviate, to a certain extent, the adverse reactions caused by traditional tumor treatment methods such as surgery, radiotherapy, and chemotherapy. Therefore, this paper systematically summarizes the direct antitumor effects of plant polysaccharides, their regulatory effects on the tumor microenvironment, and intervening many common high-incidence tumors in other ways. It also provides data support for the administration of plant polysaccharides in modern tumor drug therapy, enabling the identification of new targets and development of new drugs for tumor therapy.

Immunomodulatory Effect of Phytoactive Compounds on Human Health: A Narrative Review Integrated with Bioinformatics Approach

BACKGROUND

Immunomodulation is the modification of immune responses to control disease progression. While the synthetic immunomodulators have proven efficacy, they are coupled with toxicity and other adverse effects, and hence, the efforts were to identify natural phytochemicals with immunomodulatory potential.

OBJECTIVE

To understand the immunomodulatory properties of various phytochemicals and investigate them in Echinacea species extracts using an in silico approach.

METHODOLOGY

Several scientific database repositories were searched using different keywords: "Phytochemicals," "Alkaloids," "Polyphenols," "Flavonoids," "Lectins," "Glycosides," "Tannins," "Terpenoids," "Sterols," "Immunomodulators," and "Human Immune System" without any language restriction. Additionally, the study specifically investigated the immunomodulatory properties of Echinacea species extracts using gene expression analysis of GSE12259 from NCBI-GEO through the Bioconductor package GEOquery and limma.

RESULTS

A total of 182 studies were comprehensively analyzed to understand immunomodulatory phytochemicals. The in silico analysis highlighted key biological processes (positive regulation of cytokine production, response to tumor necrosis factor) and molecular functions (cytokine receptor binding, receptor-ligand activity, and cytokine activity) among Echinacea species extracts contributing to immune responses. Further, it also indicated the association of various metabolic pathways, i.e., pathways in cancer, cytokine-cytokine receptor interaction, NF-kappa B, PI3K-Akt, TNF, MAPK, and NOD-like receptor signaling pathways, with immune responses. The study revealed various hub targets, including CCL20, CCL4, GCH1, SLC7A11, SOD2, EPB41L3, TNFAIP6, GCLM, EGR1, and FOS.

CONCLUSION

The present study presents a cumulative picture of phytochemicals with therapeutic benefits. Additionally, the study also reported a few novel genes and pathways in Echinacea extracts by re-analyzing GSE 12259 indicating its anti-inflammatory, anti-viral, and immunomodulatory properties.

Extraction, characterization and anti-oxidant activity of polysaccharide from red Panax ginseng and Ophiopogon japonicus waste

Red ginseng and Ophiopogon japonicus are both traditional Chinese medicines. They have also been used as food in China for thousands of years. These two herbs were frequently used in many traditional Chinese patent medicines. However, the carbohydrate compositions of these two herbs were not normally used during the production of said medicine, such as Shenmai injection, resulting in a large amount of waste composed of carbohydrates. In this study, the extraction conditions were optimized by response surface methodology. The Shenmai injection waste polysaccharide was extracted by using distilled water that was boiled under the optimized conditions. The Shenmai injection waste polysaccharide (SMP) was thereby obtained. SMP was further purified by anion exchange chromatography and gel filtration. With this method, a neutral polysaccharide fraction (SMP-NP) and an acidic polysaccharide fraction (SMP-AP) were obtained. The results of structure elucidation indicated that SMP-NP was a type of levan, and SMP-AP was a typical acidic polysaccharide. SMP-NP exhibited potential stimulation activity on the proliferation of five different Lactobacilli strains. Therefore, SMP-AP could promote the antioxidant defense of IPEC-J2 cells. These findings suggest that Shenmai injection waste could be used as a resource for prebiotics and antioxidants.

Effects of simulated digestion on the structural characteristics and dendritic cell activation of longan polysaccharides

An active polysaccharide (LP) from longan was purified and characterized. LP consisted of galactose and glucose in a molar ratio of 1.5: 98.5, with a molecular weight of 4.67 × 10⁷ g/mol. The main backbone of LP was T-α-D-Glcp-[(1 → 6)-α-D-Glcp-(1 → 6)-α-D-Glcp]_n. After simulated gastrointestinal digestion, the molecular weight distribution, monosaccharide composition, and major glycosidic bonds of LP were not significantly changed. LP and digested LP (DLP) reduced phagocytosis and promoted IL-10 and IL-12 secretion of dendritic cells. In addition, the effects of LP and DLP on activating dendritic cells showed no significant difference. This study helps to illuminate the potential mode of immunomodulatory action of longan polysaccharides in vivo.

Phosphorylated polysaccharides: Applications, natural abundance, and new-to-nature structures generated by chemical and enzymatic functionalization

Polysaccharides are foreseen as serious candidates for the future generation of polymers, as they are biosourced and biodegradable materials. Their functionalisation is an attractive way to modify their properties, thereby increasing their range of applications. Introduction of phosphate groups in polysaccharide chains for the stimulation of the immune system was first described in the nineteen seventies. Since then, the use of phosphorylated polysaccharides has been proposed in various domains, such as healthcare, water treatment, cosmetic, biomaterials, etc. These alternative usages capitalize on newly acquired physico-chemical or biological properties, leading to materials as diverse as flame-resistant agents or drug delivery systems. Phosphorylated polysaccharides are found in Nature and need to be extracted to assess their biological potential. However, they are not abundant, often present complex backbones hard to characterize, and most of them have a low phosphate content. These drawbacks have pushed forward the development of chemical phosphorylation employing a wide variety of phosphorylating agents to obtain polysaccharides with a large range of phosphate content. Chemical phosphorylation requires the use of harsh conditions and toxic, petroleum-based solvents, which hinders their exploitation in the food and health industry. Over the last 20 years, although enzymes are regiospecific catalysts that work in aqueous and mild conditions, enzymatic phosphorylation has been little investigated. To date, only three families of enzymes have been used for the in vitro phosphorylation of polysaccharides. Considering the number of unresolved metabolic pathways leading to phosphorylated polysaccharides, the huge diversity of kinase sequences, and the recent progress in protein engineering one can envision native and engineered kinases as promising tools for polysaccharide phosphorylation.

Extraction, purification, structural features and biological activities of longan fruit pulp (Longyan) polysaccharides: A review

Dimocarpus longan Lour. (also called as longan) is a subtropical and tropical evergreen tree belonging to the Sapindaceae family and is widely distributed in China, Southeast Asia and South Asia. The pulp of longan fruit is a time-honored traditional medicinal and edible raw material in China and some Asian countries. With the advancement of food therapy in modern medicine, longan fruit pulp as an edible medicinal material is expected to usher in its rapid development as a functional nutrient. As one of the main constituents of longan fruit pulp, longan fruit pulp polysaccharides (LPs) play an indispensable role in longan fruit pulp-based functional utilization. This review aims to outline the extraction and purification methods, structural characteristics and biological activities (such as immunoregulatory, anti-tumor, prebiotic, anti-oxidant, anti-inflammatory and inhibition of AChE activity) of LPs. Besides, the structure-activity relationship, application prospect and patent application of LPs were analyzed and summarized. Through the systematic summary, this review attempts to provide a theoretical basis for further research of LPs, and promote the industrial development of this class of polysaccharides.

Enhanced Growth Inhibition and Apoptosis Induction in Human Colon Carcinoma HT-29 Cells of Soluble Longan Polysaccharides with a Covalent Chemical Selenylation

The selenylated polysaccharides chemically belong to the organic Se-conjugated macromolecules and have recently been attracting more and more attention due to their potential to promote body health or prevent cancers. Longan (Dimocarpus longan L.), as a subtropical fruit, contains soluble and non-digestible polysaccharides that are regarded with health care functions in the body. In this study, the longan polysaccharides (LP) were obtained via enzyme-assisted water extraction, and then chemically selenylated using a reaction system composed of HNO₃–Na₂SeO₃ to yield two selenylated products, namely, SeLP1 and SeLP2, with Se contents of 1.46 and 4.79 g/kg, respectively. The anti-cancer effects of the three polysaccharide samples (LP, SeLP1, and SeLP2) were thus investigated using the human colon cancer HT-29 cells as the cell model. The results showed that SeLP1 and SeLP2 were more able than LP to inhibit cell growth, alter cell morphology, cause mitochondrial membrane potential loss, increase intracellular reactive oxygen and [Ca²⁺]_i levels, and induce apoptosis via regulating the eight apoptosis-related genes and proteins including Bax, caspases-3/-8/-9, CHOP, cytochrome c, DR5, and Bcl-2. It was thereby proven that the selenylated polysaccharides could induce cell apoptosis via activating the death receptor, mitochondrial-dependent, and ER stress pathways. Collectively, both SeLP1 and SeLP2 showed higher activities than LP in HT-29 cells, while SeLP2 was consistently more active than SeLP1 in exerting these assessed anti-cancer effects on the cells. In conclusion, this chemical selenylation covalently introduced Se into the polysaccharide molecules and caused an enhancement in their anti-cancer functions in the cells, while higher selenylation extent was beneficial to the activity enhancement of the selenylated products.

Identification of Immune-Related lncRNA Pairs and Construction and Validation of a New Prognostic Signature of Colon Cancer

BACKGROUND

More and more evidence has shown that immune-related long noncoding ribonucleic acid (irlncRNAs) is a potential prognostic factor for colon cancer. The relevant gene pair pattern can improve the sensitivity of the prognostic model. Therefore, our present study aimed to identify irlncRNA Pairs and construct and validate a new prognostic signature in colon cancer.

METHODS

We downloaded the expression matrix of mRNA and lncRNA of patients with colon cancer and their clinical information from the public TCGA database. We obtained immune genes from the ImmPort database. Coexpression analysis was performed to identify irlncRNAs. We built an irlncRNA pair matrix by comparing the expression levels of each lncRNA pair in a cycle. Univariate Cox regression analysis, LASSO penalized regression analysis, and multivariate Cox regression analysis were performed to determine the final variables to construct the prognostic risk score model (a new signature). We draw the receiver operating characteristic (ROC) curves of the signature and clinical characteristics and determine the optimal cutoff value by the optimal Akaike Information Criterion (AIC) value. Based on the optimal cutoff value of the ROC curve of the signature, colon cancer patients were divided into the high- and low-risk groups. Then, the signature was evaluated by clinicopathological features, tumor-infiltrating immune cells, checkpoint-related biomarkers, targeted therapy, and chemotherapy.

RESULTS

We identified 8 lncRNA pairs including AC103740.1|LEF1-AS1, LINC02391|AC053503.5, WWC2-AS2|AL355916.2, AC104090.1|NEURL1-AS1, AC099524.1|AL161908.1, AC074011.1|AL078601.2, AL355916.2|LINC01723, and AP003392.4|LINC00598 from 71 differently expressed irlncRNAs. We constructed a prognostic risk score model (a new signature) using these optimal eight irlncRNA pairs. ROC curve analysis revealed that the highest AUC value of the signature was 0.776 at 1 year, with the optimal cutoff value of 1.283. Our present study also showed that the constructed signature could accurately identify adverse survival outcomes, prognostic clinicopathological features, and specify tumor invasion status. The expression of immune checkpoint-related genes and chemical drug sensitivity were related to different risk groups.

CONCLUSION

In our present study, we constructed a new irlncRNA signature of colon cancer based on the irlncRNA pairs instead of the special expression level of lncRNA. We found this signature had not only good prognostic value but also certain clinical value, which might provide a new insight into the treatment and prognosis of colon cancer.

Facile synthesis of pH-responsive sodium alginate/carboxymethyl chitosan hydrogel beads promoted by hydrogen bond

In this work, a novel synthesis strategy of sodium alginate/carboxymethyl chitosan hydrogel beads promoted by hydrogen bond was described. The beads were prepared by dropping the blends of two polymers into the citric acid solution. Besides hydrogen bonding, electrostatic interactions were also involved in the formation of the hydrogel beads. The thermal stability experiments revealed that the more the content of carboxymethyl chitosan, the better the thermal stability of the beads. The beads exhibited excellent pH sensitivity, pH reversibility, and lactoferrin loading capacity. The swelling ratio of the bead and its protein releasing profile was pH-dependent, which could prevent premature protein release in the gastric environment. Also, the circular dichroism results demonstrated that lactoferrin could maintain its structure during the loading and releasing process. The obtained results revealed that the hydrogel beads prepared in this work could be used as a potential protein carrier for oral delivery.

Minor tropical fruits as a potential source of bioactive and functional foods

Tropical fruits are defined as fruits that are grown in hot and humid regions within the Tropic of Cancer and Tropic of Capricorn, covering most of the tropical and subtropical areas of Asia, Africa, Central America, South America, the Caribbean and Oceania. Depending on the cultivation area covered, economic value and popularity these tropical fruits are divided into major and minor tropical fruits. There is an annual increment of 3.8% in terms of commercialization of the tropical fruits. In total 26 minor tropical fruits (Kiwifruit, Lutqua, Carambola, Tree Tomato, Elephant apple, Rambutan, Bay berry, Mangosteen, Bhawa, Loquat, Silver berry, Durian, Persimon, Longan, Passion fruit, Water apple, Pulasan, Indian gooseberry, Guava, Lychee, Annona, Pitaya, Sapodilla, Pepino, Jaboticaba, Jackfruit) have been covered in this work. The nutritional composition, phytochemical composition, health benefits, traditional use of these minor tropical fruits and their role in food fortification have been portrayed.

A Novel Polysaccharide Isolated From Fresh Longan (Dimocarpus longan Lour.) Activates Macrophage via TLR2/4-Mediated PI3/AKT and MyD88/TRAF6 Pathways

A novel immunomodulatory polysaccharide (LP4) with a molecular weight 6.31 × 10⁴ g/mol was purified from fresh longan pulp. It was composed of mannose, glucose, glucuronic acid, galactose, xylose, arabinose, galacturonic acid, fucose, and rhamnose in a molar percentage of 36:31:10:7:4:4:3:2:2, and mainly linked by (1→6)-β-Man, (1→4)-β-Glc and (1→6)-α-Glc. LP4 can obviously enhance the phagocytosis of macrophages and promote the proliferation of lymphocytes. After treating macrophages with LP4 (12.5–50 μg/ml), the production of IL-1β and TNF-α was significantly increased. These increases of cytokines were suppressed when the TLR2/TLR4 receptors were inhibited by anti-TLR2 and/or anti-TLR4 antibodies. Moreover, the mRNA expression of INOS, AKT, PI3K, TRAF6 and MyD88 was significantly suppressed by TLR2/TLR4 antibodies. These results indicated that LP4 induced macrophage activation mainly via the TLR2 and TLR4-induced PI3K/AKT and MyD88/TRAF6 pathways.

Exhaustive Plant Profile of “Dimocarpus longan Lour” with Significant Phytomedicinal Properties: A Literature Based-Review

Background: “Dimocarpus longan Lour” is a tropical and subtropical evergreen tree species mainly found in China, India, and Thailand; this plant, found naturally in Bangladesh, even locally, is used as “kaviraj” medication for treating different diseases, such as gastrointestinal disorders, wounds, fever, snake bites, menstrual problem, chickenpox, bone fractures, neurological disorders, and reproductive health. Different parts of this plant, especially juice pulp, pericarp, seeds, leaves, and flowers, contain a diverse group of botanical phytocompounds, and nutrient components which are directly related to alleviating numerous diseases. This literature-based review provides the most up-to-date data on the ethnomedicinal usages, phytochemical profiling, and bio-pharmacological effects of D. longan Lour based on published scientific articles. Methodology: A literature-based review was conducted by collecting information from various published papers in reputable journals and cited organizations. ChemDraw, a commercial software package, used to draw the chemical structure of the phytochemicals. Results: Various phytochemicals such as flavonoids, tannins, and polyphenols were collected from the various sections of the plant, and other compounds like vitamins and minerals were also obtained from this plant. As a treating agent, this plant displayed many biologicals activities, such as anti-proliferative, antioxidant, anti-cancer, anti-tyrosinase, radical scavenging activity, anti-inflammatory activity, anti-microbial, activation of osteoblast differentiation, anti-fungal, immunomodulatory, probiotic, anti-aging, anti-diabetic, obesity, neurological issues, and suppressive effect on macrophages cells. Different plant parts have displayed better activity in different disease conditions. Still, the compounds, such as gallic acid, ellagic acid, corilagin acid, quercetin, 4-O-methyl gallic acid, and (-)-epicatechin showed better activity in the biological system. Gallic acid, corilagin, and ellagic acid strongly exhibited anti-cancer activity in the HepG2, A549, and SGC 7901 cancer cell lines. Additionally, 4-O-methyl gallic acid and (-)-epicatechin have displayed outstanding antioxidant activity as well as anti-cancer activity. Conclusion: This plant species can be considered an alternative source of medication for some diseases as it contains a potential group of chemical constituents.

In vitro immunomodulatory activity of water-soluble glucans from fresh and dried Longan (Dimocarpus longan Lour.)

Longan (Dimocarpus longan Lour.) is a seasonal tropical fruit used by Chinese medicine in both fresh and dried pulp forms. Their polysaccharides have been reported to have biological activity. However, their composition and immune activity have not yet been disclosed. To fulfil this aim, hot water-soluble polysaccharides of fresh and dried longan pulp were fractionated according to their molecular weight by ultrafiltration (10, 50, 100 kDa cut off). The main polysaccharides recovered were 1,6-linked glucans branched at O-3 (4-8%), O-2 (1%), O-2,4 (0.1%), and O-3,4 (0.1%). The drying process promotes the solubility of the polysaccharides. These glucans from fresh and dried longan pulp have immunomodulatory activity, shown by in vitro phagocytosis, NO, TNF-α, and IL-6 macrophages production assays. They showed also to inhibit the inflammatory response induced by LPS. The immunological activity of these glucans seems to have different responses dependent on their molecular weight, related to the immune regulatory pathways.

Medicinal Plants and Isolated Molecules Demonstrating Immunomodulation Activity as Potential Alternative Therapies for Viral Diseases Including COVID-19

Plants have been extensively studied since ancient times and numerous important chemical constituents with tremendous therapeutic potential are identified. Attacks of microorganisms including viruses and bacteria can be counteracted with an efficient immune system and therefore, stimulation of body's defense mechanism against infections has been proven to be an effective approach. Polysaccharides, terpenoids, flavonoids, alkaloids, glycosides, and lactones are the important phytochemicals, reported to be primarily responsible for immunomodulation activity of the plants. These phytochemicals may act as lead molecules for the development of safe and effective immunomodulators as potential remedies for the prevention and cure of viral diseases. Natural products are known to primarily modulate the immune system in nonspecific ways. A number of plant-based principles have been identified and isolated with potential immunomodulation activity which justify their use in traditional folklore medicine and can form the basis of further specified research. The aim of the current review is to describe and highlight the immunomodulation potential of certain plants along with their bioactive chemical constituents. Relevant literatures of recent years were searched from commonly employed scientific databases on the basis of their ethnopharmacological use. Most of the plants displaying considerable immunomodulation activity are summarized along with their possible mechanisms. These discussions shall hopefully elicit the attention of researchers and encourage further studies on these plant-based immunomodulation products as potential therapy for the management of infectious diseases, including viral ones such as COVID-19.

Acute and chronic oral toxicity assessment of longan sugar extracts derived from whole fruit and from fruit pulp in rats

ETHNOPHARMACOLOGICAL RELEVANCE

Longan (Dimocarpus longan Lour.) is one of the most popular subtropical fruits. Various parts of longan, including seeds, pericarp and pulp, have long been used in traditional medicine in China, Thailand and other Asian countries. The pulp has high sugar, vitamin and mineral content as well as bioactive components. The seeds and pericarp have also been reported to contain beneficial polyphenolic compounds. Longan sugar extract from pulp (LGSP) is prepared as a conventional sugar product. Longan sugar extract from whole longan fruit (LGSW) is also offered as a health food and as a medicinal product.

AIM OF THE STUDY

The objective of this study was to identify and compare potential health hazards of both LGSW and LGSP by testing for acute and chronic oral toxicity in rats.

MATERIALS AND METHODS

In acute toxicity testing, an oral dose (20 g/kg) of either LGSW or LGSP was administered to groups of rats. Mortality and clinical signs of toxicity were observed for 24 h, and then daily for a total of 14 days. In the chronic toxicity test, either LGSW (1, 2.5 and 5 g/kg/day) or LGSP (5 g/kg/day) was administered orally for a period of 180 days. After that treatment period, the rats in the satellite groups which received the highest doses of either LGSW or LGSP were observed for an additional 28 days. The rats then underwent clinical observation, body and organ weight measurement, hematological and biochemical analyses, and histopathological examination.

RESULTS

In the acute toxicity study, the oral administration of LGSP or LGSW in either pellet or syrup formulations did not cause mortality or any pathological abnormalities. In the chronic toxicity study, neither LGSW nor LGSP resulted in death or in any changes in behavior of the rats. All hematological and serum biochemical values of both the LGSW- and LGSP-treated groups were within the normal ranges. No histopathological abnormalities of any internal organs were observed.

CONCLUSION

The safety of longan sugar extract made from whole fruit (pulp, seeds and pericarb) is comparable to that of longan sugar extract made from pulp alone.

Glucose-rich polysaccharide from dried 'Shixia' longan activates macrophages through Ca2+ and CR3- mediated MAPKs and PI3K-AKT pathways

A water-soluble glucose-rich polysaccharide from dried 'Shixia' longan pulp (LPsx) has been isolated for the first time, and its structure and immuno-regulatory mechanism were studied. LPsx is a hetero-polysaccharide with the average molecular weight 4102 g/mol. It was mainly consisted of glucose (95.9%), and small proportions of arabinose (2.1%), galactose (1.0%), mannose (0.6%), and xylose (0.4%). As analyzed by NMR, LPsx was mainly composed of (1 → 6)-α-d-glucose and (1 → 6)-β-d-glucose, branched with α-d-glucose-(1→. The immunomodulatory activity study showed that LPsx significantly increased the phagocytosis of macrophages, and strongly promoted the production of NO, IL-1β, IL-6 and TNF-α. Moreover, LPsx could inhibit the inflammatory response induced by lipopolysaccharide. The immuno-regulatory mechanism of LPsx was studied using RNA- sequencing and receptors activity analyses. It was found that LPsx induced macrophage activation via Ca²⁺ and CR3-mediated MAPKs and PI3K-AKT signaling pathways. The results would be helpful for revealing the health promoting mechanism of dried 'Shixia' longan in traditional Chinese medicine.

Trends in the extraction, purification, characterisation and biological activities of polysaccharides from tropical and sub-tropical fruits - A comprehensive review

Tropical and sub-tropical fruits are tremendous sources of polysaccharides (PSs), which are of great interest in the human welfare system as natural medicines, food and cosmetics. This review paper aims to highlight the recent trends in extraction (conventional and non-conventional), purification and analytic techniques of fruit polysaccharides (FPSs). The chemical structure and biological activities, such as immunomodulatory, anti-cancer, anti-oxidant, anti-inflammatory, anti-viral, anti-coagulant and anti-diabetic effects, of PSs extracted from 53 various fruits were compared and discussed. With this wide coverage, a total of 172 scientific articles were reviewed and discussed. This comprehensive survey from previous studies suggests that the FPSs are non-toxic and highly biocompatible. In addition, this review highlights that FPSs might be excellent functional foods as well as effective therapeutic drugs. Finally, the future research advances of FPSs are also described. The content of this review will promote human wellness-based food product development in the future.

Longan pulp polysaccharides relieve intestinal injury in vivo and in vitro by promoting tight junction expression

The integrity of the intestinal mucosal barrier is important for the health of the host. In this study, longan pulp polysaccharides (LP) prevented the intestinal mucosal injury by increasing the expression of mucin 2, tight junction proteins zonulae occludens-1 (ZO-1), claudin-1, claudin-4, and adherens junction E-cadherin in cyclophosphamide-treated mice. To further identify the principle bioactive component of LP, four acidic polysaccharides (LPIa, LPIIa, LPIIIa, and LPIVa) were purified, and their intestinal protection activity in vitro was compared. LPIa, LPIIa, and LPIIIa displayed an ability to increase mRNA expression of ZO-1, claudin-1, occludin, and E-cadherin in differentiated Caco-2 cells, especially LPIa. LPIa has specific structure characteristics: porous surface structure, a high molecular weight (1.47 × 10⁵ Da), and two specific glycosidic linkages of α-Araf-(1→ and →5)-α-Araf-(1→. These structure characteristics might primarily contribute to greater intestinal barrier protective effect of LPIa.

Characterizations and immunostimulatory activities of a polysaccharide from Arnebia euchroma (Royle) Johnst. roots

A polysaccharide from Arnebia euchroma (Royle) Johnst. named ARP, was obtained and purified by the hot water extraction, ethanol precipitation and deproteinization of TCA. The molecular weight of the polysaccharide fraction of ARP was calculated to be 1.23 × 10⁴ Da from a calibration curve obtained with dextran standards. Monosaccharide composition analysis revealed that ARP was composed of Gal, Ara, Glu, Man, Rha and Fuc at a molar ratio of 53.8:21.3:11.7:6.8:4.3:2.2. Methylation analysis suggested that ARP was likely an arabinogalactan and that its backbone mainly consisted of Galp residues of 1,6‑linkages and Ara residues of 1,5‑ or 1,3‑linkages. The in vitro experiment indicated that ARP enhanced B- and T-lymphocyte proliferation. A dose-dependent relationship was observed, and a dose of 200 μg/mL resulted in the highest cell viability. In addition, ARP significantly stimulated the production of the cytokine, interferon-γ (IFN-γ), and enhanced B- and T-lymphocyte proliferation. Meanwhile, ARP had little effect on interleukin-2 (IL-2) production. The experiments of the effect of ARP on the activation of macrophage in vitro indicated that ARP significantly enhanced the production of TNF-α, IL-6 and IL-1β which suggested the polysaccharide induced the functional activation of macrophage.

Exopolysaccharides from the fungal endophytic Fusarium sp. A14 isolated from Fritillaria unibracteata Hsiao et KC Hsia and their antioxidant and antiproliferation effects

Exopolysaccharides (EPSs) are high-molecular-weight carbohydrates with a wide range of biophysiological activities, such as antioxidant activity, immunostimulatory activity, antitumor activity, hepatoprotective activity, and antifatigue effects. In the present work, two water-soluble EPSs, namely, A14EPS-1 and A14EPS-2, were isolated and purified from the fungal endophytic strain A14 using ethanol precipitation, DEAE-cellulose ion exchange chromatography and Sepharose G-150 gel filtration chromatography. A14EPS-1 (∼2.4 × 10⁴ Da, the major fraction) was mainly composed of mannose, rhamnose, glucose, galactose, xylose and arabinose with a molar ratio of 0.31:0.55:10.00:0.34:0.03:0.06. The major monosaccharide of A14EPS-1 was pyranose, which was connected by α-glycosidic linkages. And the side chains of A14EPS-1 may be composed of rhamnose, arabinose, glucose and galactose; moreover, the backbone of A14EPS-1 may be composed of rhamnose, xylose, arabinose and glucose. A14EPS-2 (∼0.5 × 10⁴ Da) was mainly composed of mannose, rhamnose, glucose, galactose, xylose and arabinose in a ratio of 0.16:0.88:10.00:0.39:0.06:0.06. Pyranose was observed in both the α- and β-configurations in A14EPS-2, and the α configuration was dominant. In addition, the results of the bioactivity assays indicated that both A14EPS-1 and A14EPS-2 had moderate antioxidant activity in vitro, and A14EPS-2 showed a moderate antiproliferation effect on human hepatocellular carcinoma HepG2 cells.

Isolation, purification, characterization and bioactivities of a glucan from the root of Pueraria lobata

The root of Pueraria lobata is considered to be a medicinal and edible herb for the treatment of diabetes, and it has a long history of application in China.

Chinese materia medica used in medicinal diets

ETHNOPHARMACOLOGICAL RELEVANCE

Medicinal diets have a history of more than 2000 years. Locally referred to as yaoshan (Chinese: ), a medicinal diet is understood in China as a dietary product that combines herbs and food with the purpose of preventing and treating diseases or improving health under the guidance of traditional Chinese medicine theory. Medicinal diets are used in Chinese people's daily life and in specialized restaurants. Hundreds of Chinese materia medica (CMM) are used in medicinal diets; however, a comprehensive evaluation of medicinal diets is lacking.

AIMS OF THE STUDY

This is an exploratory study that aims to identify the CMM that are most frequently used in medicinal diets and to provide an updated view of the current situation of medicinal diets in China.

MATERIALS AND METHODS

A field study of 1221 people in 32 Chinese provinces was conducted over a period of approximately 6 months and included various types of interviews as well as a written questionnaire. Two approaches were used to analyse the data collected in the survey: (1) estimating the frequency of CMM consumed in daily diets; and (2) collecting CMM used in medicinal diet restaurants. Complementary information on the selected CMM was obtained from relevant databases, including PubMed, Google Scholar, Baidu Scholar, CNKI, and Web of Science.

RESULTS

Ten CMM were reported as commonly used by more than 50% of the participants. Among these 10 species, most medicinally used parts were seeds and fruits. Pharmacological data from the literature revealed that these species are associated with a wide spectrum of biological properties, including antitumour (80%), antioxidant (50%), anti-diabetic (40%), antilipemic (40%), anti-aging (40%), antimicrobial (40%) and cardioprotective (40%) activities. Our survey shows that most medicinal diet restaurants are located in the eastern part of China, with the greatest numbers being found in Beijing and Guangzhou. Only Dioscoreae Rhizoma, Lycii Fructus, Chrysanthemi Flos and Longan Arillus were frequently consumed both in daily diets and at medicinal diet restaurants. Some of the similarities shared by these 4 species include an extensive history of use (>2000 years); a sweet flavour; and antioxidant, antidiabetic, antilipemic and cardioprotective effects.

CONCLUSIONS

The 10 most commonly consumed CMM possess various biological effects that are currently target the most frequent health problems for the majority of the population. The development of medicinal diet restaurants has certain regional restrictions and is associated with the local climate environment and dietary culture. The data revealed by this study provided useful information for commercial exploitation of medicinal diets and their components and serve as a basis for further studies on various aspects of medicinal diets.

Extraction, Characterization and Immunological Activity of Polysaccharides from Rhizoma gastrodiae

A response surface and Box-Behnken design approach was applied to augment polysaccharide extraction from the residue of Rhizoma gastrodiae. Statistical analysis revealed that the linear and quadratic terms for three variables during extraction exhibited obvious effects on extraction yield. The optimum conditions were determined to be a liquid-to-solid ratio of 54 mL/g, an extraction temperature of 74 °C, an extraction time of 66 min, and three extractions. These conditions resulted in a maximum Rhizoma gastrodiae polysaccharide (RGP) extraction yield of 6.11% ± 0.13%. Two homogeneous polysaccharides (RGP-1a and RGP-1b) were obtained using DEAE cellulose-52 and Sephadex G-100 columns. The preliminary characterization of RGP-1a and RGP-1b was performed using HPLC-RID, HPGPC, and FTIR. Tests of the immunological activity in vitro showed that the two polysaccharides could significantly stimulate macrophages to release NO and enhance phagocytosis in a dose-dependent manner. In particular, RGP-1b (200 μg/mL) and LPS (2 μg/mL) had almost the same influence on the NO production and phagocytic activity of RAW 264.7 macrophages (p > 0.05). All the data obtained indicate that RGP-1a and RGP-1b have the potential to be developed as a health food.

Isolation and characterization of antioxidant polysaccharides (PKCP-D70-2-a and PKCP-D70-2-b) from the Pinus koraiensis pinecone

Water-soluble polysaccharides from Pinus koraiensis pinecone was fractionated using DEAE cellulose-52 and Sephadex G-100 successively to obtain two eluents named PKCP-D₇₀-2-a and PKCP-D₇₀-2-b.

Anti-Hepatitis C Virus Activity of a Crude Extract from Longan (Dimocarpus longan Lour.) Leaves

Infection with hepatitis C virus (HCV) results in hepatitis C, a disease characterized by chronic infection, cirrhosis, and hepatocellular carcinoma. Currently, the standard therapy is a combination of pegylated interferon-α plus ribavirin with NS3 protease inhibitors. Addition of NS3 protease inhibitors to the standard therapy improves response rates; however, use of NS3 protease inhibitors is also associated with significant adverse effects and an increase in the overall cost of treatment. Therefore, there is a need to develop safe and inexpensive drugs for the treatment of HCV infections. In this study, we examined the antiviral activity of a crude extract from Dimocarpus longan leaves against HCV (genotype 2a strain JFH1). The D. longan crude extract (DL-CE) exhibited anti-HCV activity with a 50% effective concentration (EC50) of 19.4 μg/ml without cytotoxicity. A time-of-addition study demonstrated that DL-CE has anti-HCV activity at both the entry and post-entry steps and markedly blocks the viral entry step through direct virucidal activity with marginal inhibition of virion assembly. Co-treatment of DL-CE with cyclosporine A, an immunosuppressant or telaprevir, an NS3 protease inhibitor, resulted in additive and synergistic antiviral effects, respectively. Our findings suggest that DL-CE may be useful as an add-on therapy candidate for treating HCV infections.

Purification and Structural Identification of Polysaccharides from Bamboo Shoots (Dendrocalamus latiflorus)

Three kinds of polysaccharides, namely, BSP1A, BSP2A, and BSP3B, were isolated from raw bamboo shoot (Dendrocalamus latiflorus) after purification and classification by DEAE cellulose-52 (ion-exchange chromatography) and Sephadex G-50. The molecular weights of BSP1A, BSP2A, and BSP3B were 10.2, 17.0 and 20.0 kDa, respectively, which were measured through GPC (gel performance chromatography) methods. BSP1A contained arabinose, glucose, and galactose in a molar ratio of 1.0:40.6:8.7. BSP2A and BSP3B contained arabinose, xylose, glucose, and galactose in molar ratios of 6.6:1.0:5.2:10.4 and 8.5:1.0:5.1:11.1, respectively. The existence of the O-glycopeptide bond in BSP1A, BSP2A, and BSP3B was demonstrated by β-elimination reaction. FTIR spectra of the three polysaccharides showed that both BSP2A and BSP3B contained β-D-pyranose sugar rings. However, BSP1A exhibited both β-D-pyranose and α-D-pyranose sugar rings. Congo red test indicated that BSP1A and BSP2A displayed triple helix structures, but BSP3B did not. NMR spectroscopy revealed that BSP1A may exhibit a β-1,6-Glucan pyran type as the main link, and few 1,6-glycosidic galactose pyranose and arabinose bonds were connected; BSP2A mainly demonstrated → 5)β-Ara(1 → and → 3)β-Gal(1 → connection. Furthermore, BSP3B mainly presented → 3)β-Glu(1 → and → 3)β-Gal(1 → connection and may also contain few other glycosidic bonds.

Characterization and antihyperglycemic activity of a polysaccharide from Dioscorea opposita Thunb roots

A polysaccharide DOTP-80 from Dioscorea opposita Thunb was obtained by using the method of acid water-extraction and ethanol-precipitation. After being purified by chromatography, the structure characteristics of DOTP-80 were established. Based on the calibration curve obtained with standard dextrans, the molecular weight of the polysaccharide fraction DOTP-80 was calculated to be 123 kDa. The results of Infrared spectrum (FT-IR) indicated that the polysaccharide contained the α-configuration of sugar units. GC-MS analysis revealed that DOTP-80 was mainly composed of mannose and glucose. Alloxan-induced diabetic rats and mice models were developed to evaluate the in vivo hypoglycemic activity of the polysaccharide. The results indicated that a high dose DOTP-80 (400 mg/kg) had strong hypoglycemic activity. Moreover, DOTP-80 could increase the level of antioxidant enzymes (SOD) activity in alloxan-induced diabetic mice and stimulate an increase in glucose disposal in diabetic rats. Therefore, the polysaccharide DOTP-80 should be evaluated as a candidate for future studies on diabetes mellitus.