Lotus (Nelumbo nucifera Gaertn) plumule polysaccharide protects the spleen and liver from spontaneous inflammation in non-obese diabetic mice by modulating pro-/anti-inflammatory cytokine gene expression

Molecular Mechanisms Underlying the Therapeutic Potential of Plant-Based α-Amylase Inhibitors for Hyperglycemic Control in Diabetes

BACKGROUND

Diabetes mellitus (DM), arising from pancreatic β-cell dysfunction and disrupted alpha-amylase secretion, manifests as hyperglycemia. Synthetic inhibitors of alphaamylase like acarbose manage glucose but pose adverse effects, prompting interest in plantderived alternatives rich in antioxidants and anti-inflammatory properties.

OBJECTIVE

The current review investigates plant-based alpha-amylase inhibitors, exploring their potential therapeutic roles in managing DM. Focusing on their ability to modulate postprandial hyperglycemia by regulating alpha-amylase secretion, it assesses their efficacy, health benefits, and implications for diabetes treatment.

METHODS

This review examines plant-derived alpha-amylase inhibitors as prospective diabetic mellitus treatments using PubMed, Google Scholar, and Scopus data.

RESULTS

Plant-derived inhibitors, including A. deliciosa, B. egyptiaca, and N. nucifera, exhibit anti-inflammatory and antioxidant properties, effectively reducing alpha-amylase levels in diabetic conditions. Such alpha-amylase inhibitors showed promising alternative treatment in managing diabetes with reduced adverse effects.

CONCLUSION

The current literature concludes that plant-derived alpha-amylase inhibitors present viable therapeutic avenues for diabetes management by modulating alpha-amylase secretion by regulating inflammatory, oxidative stress, and apoptotic mechanisms involved in the pathogenesis of diabetes. Further investigation into their formulations and clinical efficacy may reveal their more comprehensive diabetes therapeutic significance, emphasizing their potential impact on glucose regulation and overall health.

Preparation, structural characterization, and biological activities of lotus polysaccharides: A review

Lotus (Nelumbo nucifera), belonging to the family of Nelumbonaceae, is a beautiful aquatic perennial plant. It has been used as an ancient horticulture plant and famous agricultural crop for thousands of years. Modern phytochemical and pharmacological experiments have proved that polysaccharide is one of the most pivotal bioactive constituents of lotus. Hence, the systematic review covering the fundamental research advances and developing prospects of N. nucifera polysaccharides (NNPs) is an urgent demand to provide theoretical basis for their further research and application. The present review summarizes current emerging research progresses on the polysaccharides isolated from lotus, and it focuses on advanced extraction and purification methods, unique structural features, engaging biological activities, potential molecular mechanisms, as well as the relationship of structure and activity of NNPs. This review sheds light on the potential values of NNPs in affording functionally bioactive agents in food industry or therapeutically effective medicines for health care. In addition, this review will provide valuable insights for further commercial product development and promising industrial application of NNPs in both of the fundamental research communities and food or pharmaceutical industries in future.

A review on extraction, composition, structure, and biological activities of polysaccharides from different parts of Nelumbo nucifera

Nelumbo nucifera (lotus plant) is an important member of the Nelumbonaceae family. This review summarizes the studies conducted on it since the past 15 years to provide an understanding on future areas of focus. Different parts of this plant, that is, leaves, roots, and seeds, have been used as food and for the treatment of various diseases. Polysaccharides have been extracted from different parts using different methods. The manuscript reviews the methods of extraction of polysaccharides used for leaves, roots, and seeds, along with their yield. Some methods can provide better yield while some provide better biological activity with low yield. The composition and structure of extracted polysaccharides have been determined in some studies. Although monosaccharide composition has been determined in various studies, too little information about the structure of polysaccharides from N. nucifera is available in the current literature. Different useful biological activities have been explored using in vivo and in vitro methods, which include antioxidant, antidiabetic, antitumor, anti-osteoporotic, immunomodulatory, and prebiotic activities. Antitumor activity from polysaccharides of lotus leaves is yet to be explored, besides lotus root has been underexplored as compared to other parts (leaves and seeds) according to our literature survey. Studies dedicated to the successful use of combination of extraction methods can be conducted in future. The plant provides a therapeutic as well as nutraceutical potential; however, antimicrobial activity and synergistic relationships of polysaccharides from different parts of the plant need further exploration.

Recent advances on bioactive compounds, biosynthesis mechanism, and physiological functions of Nelumbo nucifera

Nelumbo nucifera Gaertn, commonly known as lotus, is a genus comprising perennial and rhizomatous aquatic plants, found throughout Asia and Australia. This review aimed to cover the biosynthesis of flavonoids, alkaloids, and lipids in plants and their types in different parts of lotus. This review also examined the physiological functions of bioactive compounds in lotus and the extracts from different organs of the lotus plant. The structures and identities of flavonoids, alkaloids, and lipids in different parts of lotus as well as their biosynthesis were illustrated and updated. In the traditional medicine systems and previous scientific studies, bioactive compounds and the extracts of lotus have been applied for treating inflammation, cancer, liver disease, Alzheimer's disease, etc. We suggest future studies to be focused on standardization of the extract of lotus, and their pharmacological mechanisms as drugs or functional foods. This review is important for the lotus-based food processing and application.

Bioactive polysaccharides from lotus as potent food supplements: a review of their preparation, structures, biological features and application prospects

Lotus is a famous plant of the food and medicine continuum for millennia, which possesses unique nutritional and medicinal values. Polysaccharides are the main bioactive component of lotus and have been widely used as health nutritional supplements and therapeutic agents. However, the industrial production and application of lotus polysaccharides (LPs) are hindered by the lack of a deeper understanding of the structure-activity relationship (SAR), structural modification, applications, and safety of LPs. This review comprehensively comments on the extraction and purification methods and structural characteristics of LPs. The SARs, bioactivities, and mechanisms involved are further evaluated. The potential application and safety issues of LPs are discussed. This review provides valuable updated information and inspires deeper insights for the large scale development and application of LPs.

Extraction, purification, structural characteristics, biological activities, and application of the polysaccharides from Nelumbo nucifera Gaertn. (lotus): A review

Nelumbo nucifera Gaertn. (lotus) is a widely distributed plant with a long history of cultivation and consumption. Almost all parts of the lotus can be used as foodstuff and nourishment, or as an herb. It is noteworthy that the polysaccharides obtained from lotus exhibit surprisingly and satisfying biological activities, which explains the various benefits of lotus to human health, including anti-diabetes, anti-osteoporosis, antioxidant, anti-inflammatory, anti-tumor, etc. Here, we systematically review the recent major studies on extraction and purification methods of polysaccharides from different parts (rhizome, seed, leaf, plumule, receptacle and stamen) of lotus, as well as the characterization of their chemical structure, biological activity and structure-activity relationship, and the applications of lotus polysaccharides in different fields. This article will give an updated and deeper understanding of lotus polysaccharides and provide theoretical basis for their further research and application in human health and manufacture development.

Extraction optimization, physicochemical property, antioxidant activity, and α-glucosidase inhibitory effect of polysaccharides from lotus seedpods

BACKGROUND

Lotus seedpods are an agricultural by-product of lotus (Nelumbo nucifera Gaertn.), which is widely cultivated in Southeast Asia and Australia. Most lotus seedpods are considered waste and are abandoned or incinerated, resulting in significant waste of resources and heavy environmental pollution. For recycling lotus seedpods, the extraction optimization, physicochemical properties, antioxidant activity, and α-glucosidase inhibitory effect of the polysaccharides contained therein were investigated in this study.

RESULTS

Hot water extraction of lotus seedpod polysaccharides was optimized by using a response surface methodology combined with a Box-Behnken design, with the optimum conditions being as follows: a liquid/solid ratio of 25.0 mL g^-1 , an extraction temperature of 98.0 °C, and an extraction time of 138.0 min. Under these conditions, an experimental yield of 5.88 ± 0.06% was obtained. Physicochemical analyses suggested that lotus seedpod polysaccharides belong to acidic heteropolysaccharides and are principally composed of rhamnose, arabinose, galactose, glucose, mannose, and galacturonic acid. The polysaccharides content has a broad molecular weight distribution (2.15 × 10⁵ to 1.77 × 10⁷  Da), an α-configuration, and mainly possesses smooth and sheet-like structures. Biological evaluations showed that the polysaccharides possessed good scavenging activity on 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt, 1,1-diphenyl-2-picryl-hydrozyl, and hydroxyl radicals, and exerted an obvious inhibitory effect on α-glucosidase activity. Moreover, the polysaccharides content was determined to be a mixed-type noncompetitive inhibitor of α-glucosidase.

CONCLUSION

The results indicate that lotus seedpod polysaccharides have potential as natural antioxidants and hypoglycaemic substitutes. This study provides the theoretical bases for the exploitation and application of polysaccharides from lotus seedpod by-product resources. © 2022 Society of Chemical Industry.

Structural characterization and in vitro anti-inflammatory estimation of an unusual pectin linked by rhamnogalacturonan I and xylogalacturonan from lotus plumule

A novel homogenous polysaccharide LPWF together with its three acid hydrolysis products LPWF1-3 were isolated and prepared from lotus plumule (germs of Nelumbo nucifera). LPWF was composed of rhamnose (Rha), arabinose (Ara), galactose (Gal), xylose (Xyl), and galacturonic acid (GalA) in the molar ratio of 7.3: 34.0: 7.0: 19.1: 32.6 with a molecular weight of 567.6 kDa. The structure of LPWF was elucidated by methylation and NMR analysis of LPWF1-3 and a follow-up structural assembling aided by high-resolution mass spectrometry mapping of oligosaccharides and ROSEY spectra. LPWF was characterized as an unusual pectin linked by rhamnogalacturonan I (RGI, composed of LPWF1-2) and xylogalacturonan (XGA, LPWF3). LPWF1 was an arabinan peeled from the RGI part with a 1,5-linked backbone branching on the O-2 position, while LPWF2 was the remaining part of RGI composed of Rha (36.1%), Gal (17.8%), and GalA (43.7%). LPWF3 was identified as the XGA part with a backbone of α-1,4-linked GalA and branches of mono-xylose substitutions on the O-3 of GalA. LPWF (25 μg/mL) demonstrated significant inhibitions on the expression of IL-1β, IL-6, and TNF-α in LPS-stimulated primary murine microglia cultures. LPWF1 and 2 showed selectively and significantly inhibitory activity against the expression of IL-1β.

An updated review on pharmacological properties of neferine-A bisbenzylisoquinoline alkaloid from Nelumbo nucifera

Phytochemicals have recently received a lot of recognition for their pharmacological activities such as anticancer, chemopreventive, and cardioprotective properties. In traditional Indian and Chinese medicine, parts of lotus (Nelumbo nucifera) such as lotus seeds, fruits, stamens, and leaves are used for treating various diseases. Neferine is a bisbenzylisoquinoline alkaloid, a major component from the seed embryos of N. nucifera. Neferine is effective in the treatment of high fevers and hyposomnia, as well as arrhythmia, platelet aggregation, occlusion, and obesity. Neferine has been found to have a variety of therapeutic effects such as anti-inflammatory, anti-oxidant, anti-hypertensive, anti-arrhythmic, anti-platelet, anti-thrombotic, anti-amnesic, and negative inotropic. Neferine also exhibited anti-anxiety effects, anti-cancerous, and chemosensitize to other anticancer drugs like doxorubicin, cisplatin, and taxol. Induction of apoptosis, autophagy, and cell cycle arrest are the key pathways that underlying the anticancer activity of neferine. Therefore, the present review summarizes the neferine biosynthesis, pharmacokinetics, and its effects in myocardium, cancer, chemosensitizing to cancer drug, central nervous system, diabetes, inflammation, and kidney diseases. PRACTICAL APPLICATIONS: Natural phytochemical is gaining medicinal importance for a variety of diseases like including cancer, neurodegenerative disorder, diabetes, and inflammation. Alkaloids and flavonoids, which are abundantly present in Nelumbo nucifera have many therapeutic applications. Neferine, a bisbenzylisoquinoline alkaloid from N. nucifera has many pharmacological properties. This present review was an attempt to compile an updated pharmacological action of neferine in different disease models in vitro and in vivo, as well as to summarize all the collective evidence on the therapeutic potential of neferine.

Polysaccharide Derived from Nelumbo nucifera Lotus Plumule Shows Potential Prebiotic Activity and Ameliorates Insulin Resistance in HepG2 Cells

Polysaccharides are key bioactive compounds in lotus plumule tea, but their anti-diabetes activities remain unclear. The purpose of this study was to investigate the prebiotic activities of a novel polysaccharide fraction from the Nelumbo nucifera lotus plumule, and to examine its regulation of glucose metabolism in insulin-resistant HepG2 cells. The N. nucifera polysaccharide (NNP) was purified after discoloration, hot water extraction, ethanol precipitation, and DEAE-cellulose chromatography to obtain purified polysaccharide fractions (NNP-2). Fourier transform infrared spectroscopy was used to analyze the main structural characteristics and functional group of NNP-2. Physicochemical characterization indicated that NNP-2 had a molecular weight of 110.47 kDa and consisted of xylose, glucose, fructose, galactose, and fucose in a molar ratio of 33.4:25.7:22.0:10.5:8.1. The prebiotic activity of NNP-2 was demonstrated in vitro using Lactobacillus and Bifidobacterium. Furthermore, NNP-2 showed bioactivity against α-glucosidase (IC₅₀ = 97.32 µg/mL). High glucose-induced insulin-resistant HepG2 cells were used to study the effect of NNP-2 on glucose consumption, and the molecular mechanism of the insulin transduction pathway was studied using RT-qPCR. NNP-2 could improve insulin resistance by modulating the IRS1/PI3K/Akt pathway in insulin-resistant HepG2 cells. Our data demonstrated that the Nelumbo nucifera polysaccharides are potential sources for nutraceuticals, and we propose functional food developments from the bioactive polysaccharides of N. nucifera for the management of diabetes.

Polysaccharides and polyphenol in dried Morinda citrifolia fruit tea after different processing conditions: Optimization analysis using response surface methodology

The increasing popularity of Morinda citrifolia has many medical and health benefits because of its rich polysaccharides (PSC) and polyphenols (PPN). It has become popular to brew the dry M. citrifolia fruit slice as tea in some regions of China. In this study, optimize the extraction parameters of M. citrifolia fruit tea polysaccharides and polyphenols using response surface methodology. The results indicated the highest PSC yield of 17% at 46 °C for 11 min and the ratio of water/M. citrifolia fruit powder was 78 mL/g. The optimum extraction of PPN was at 95 °C for 10 min and the ratio of water/M. citrifolia fruit powder 90 mL/g, with 8.93% yield. Using dry M. citrifolia fruit slices as a tea is reported for the first time. Based on the results, the maximum level of PSC can be obtained under condition by infusing about four dried M. citrifolia fruit slice with average thickness and size in warm boiled water for 11 min, taking a 300 mL cup (300 mL of water) for example. The maximum level of PPN can be obtained by adding three slices of dried M. citrifolia fruit slice to boiled water for 10 min. Considering the powder used in our study, the further pulverization of cutting into powder is more conducive to material precipitation. This study provides a scientific basis for obtaining PSC and PPN from dry M. citrifolia fruit slice tea by brewing.

M1 Polarization but Anti-LPS-Induced Inflammation and Anti-MCF-7 Breast Cancer Cell Growth Effects of Five Selected Polysaccharides

Five potential polysaccharides from guava seed (GSPS), common buckwheat (CBPS), bitter buckwheat (BBPS), red Formosa lambsquarters (RFLPS), and yellow Formosa lambsquarters (YFLPS) were selected to measure their effects on mouse peritoneal macrophages in the absence or presence of lipopolysaccharide (LPS). Macrophage-conditioned media (MCM) in the absence or presence of 5 selected polysaccharides were prepared to treat MCF-7 cells. The cell viability was determined using 3-(4,5-dimethylthiazol-2-diphenyl)-2,5-tetrazolium bromide (MTT) assay. Proinflammatory (also known as M1 type) (interleukin- (IL-) 1β, IL-6 and tumor necrosis factor- (TNF-) α) and anti-inflammatory (also known as M2 type) (IL-10) cytokines secreted by macrophages were determined using ELISA. The relationship between MCF-7 cell growth and M1/M2 cytokine secretion profiles in the corresponding MCM were delineated. The results showed that 5 selected polysaccharides, except BBPS, significantly (P < 0.05) and dose-dependently increased M1 (IL-1β + IL-6 + TNF-α)/M2 (IL-10) cytokine secretion ratios by macrophages in the absence of LPS, suggesting that four selected polysaccharides have M1 polarization property. However, all of 5 selected polysaccharides significantly (P < 0.05) decreased proinflammatory (IL-1β + IL-6 + TNF-α)/anti-inflammatory (IL-10) cytokine secretion ratios by LPS-stimulated macrophages, exhibiting that all of the 5 selected polysaccharides, particularly GSPS, have anti-inflammatory potential. All MCM prepared with these selected polysaccharides (except YFLPS) significantly enhanced their inhibitory effects on MCF-7 cell growth. A negative correlation was noted between MCF-7 cell viabilities and M1/M2 cytokine secretion ratios ((IL-6 + TNF-α)/IL-10) in the corresponding MCM, suggesting that increases in M1 macrophages in the tumor microenvironment might inhibit MCF-7 cell growth. Particular polysaccharides including RFLPS, GSPS, YFLPS, and CBPS may increase the percentage of M1 macrophages in the tumor environment and further inhibit MCF-7 cell growth via immunotherapy.

Neferine inhibits proliferation, migration and invasion of U251 glioma cells by down-regulation of miR-10b

BACKGROUND

Glioma is a common brain tumor, which is a serious threat to the life and health of human with high mortality rate. Recently, neferine (NEF) has been reported to play an important role in various cancers. In the study, we aimed to investigate the effect of NEF on human glioma cell line U251.

METHODS

U251 cells were pre-treated with different concentrations of NEF, and then CCK-8, BrdU, flow cytometry and transwell assays were used to test cell proliferation, apoptosis, migration and invasion. Subsequently, the expression vectors of miR-10b mimic and miR-10b inhibitor were transfected into U251 cells, and the relative expression of miR-10b was examined by qRT-PCR. The main proteins of CyclinD1/p53/p16, pro-Caspase-3/-9, cleaved-Caspase-3/-9, MMP-9, Vimentin, PTEN/PI3K/AKT and p38MAPK signal pathways were determined by western blot assay.

RESULTS

NEF significantly suppressed cell proliferation, and induced apoptosis, as well as regulated CyclinD1, p53, p16 and cleaved-Caspase-3/-9 expressions in U251 cells. Moreover, NEF inhibited cell migration, invasion and decreased MMP-9 and Vimentin expression in U251 cells. Additionally, miR-10b expression was down-regulated in NEF-stimulated cells, and overexpression of miR-10b reversed the regulatory effects of NEF on U251 cells proliferation, migration, invasion and apoptosis. Additionally, we found that PTEN was a direct target of miR-10b in U251 cells. Besides, NEF deactivated PTEN/PI3K/AKT and p38MAPK signal pathways by down-regulation of miR-10b in U251 cells.

CONCLUSIONS

These results suggested that NEF exerted anti-tumor effect by down-regulation of miR-10b and deactivation of PTEN/PI3K/AKT and p38MAPK signal pathways in glioma cells. These findings might provide a novel therapeutic strategy for glioma.

Optimization of microwave-assisted extraction of bioactive alkaloids from lotus plumule using response surface methodology

In this work, a fast and efficient microwave-assisted extraction (MAE) method was developed to extract main bioactive alkaloids from lotus plumue. To optimize MAE conditions, three main factors were selected using univariate approach experiments, and then central composite design (CCD). The optimal extraction conditions were as follows: methanol concentration of 65%, microwave power of 200 W, and extraction time of 260 s. An high performance liquid chromatography-diode array detector (HPLC-DAD) method was established to quantitatively analyze these phytochemicals in different lotus plumule samples and in different part of lotus. Chromatographic separation was carried out on an Agilent Zorbax Extend-C18 column (4.6 mm×150 mm, 3.5 µm). Gradient elution was applied with the mobile phase constituted with 0.1% triethylamine in water (A) and acetonitrile (B): 40%-70% B at 0-8 min, 70%-100% B at 8-9 min, 100% B for 2 min, and then equilibrated with 40% B for 2 min.

Cytotoxic, Antitumor and Immunomodulatory Effects of the Water-Soluble Polysaccharides from Lotus (Nelumbo nucifera Gaertn.) Seeds

Lotus is an edible and medicinal plant, and the extracts from its different parts exhibit various bioactivities. In the present study, the hot water-soluble polysaccharides from lotus seeds (LSPS) were evaluated for their cancer cell cytotoxicity, immunomodulatory and antitumor activities. LSPS showed significant inhibitory effects on the mouse gastric cancer MFC cells, human liver cancer HuH-7 cells and mouse hepatocarcinoma H22 cells. The animal studies showed that LSPS inhibited tumor growth in H22 tumor-bearing mice with the highest inhibition rate of 45.36%, which is comparable to that induced by cyclophosphamide (30 mg/kg) treatment (50.79%). The concentrations of white blood cells were significantly reduced in cyclophosphamide-treated groups (p < 0.01), while LSPS showed much fewer side effects according to the hematology analysis. LSPS improved the immune response in H22 tumor-bearing mice by enhancing the spleen and thymus indexes, and increasing the levels of serum cytokines including tumor necrosis factor-α and interleukin-2. Moreover, LSPS also showed in vivo antioxidant activity by increasing superoxide dismutase activity, thus reducing the malondialdehyde level in the liver tissue. These results suggested that LSPS can be used as an antitumor and immunomodulatory agent.

Current Advances in the Metabolomics Study on Lotus Seeds

Lotus (Nelumbo nucifera), which is distributed widely throughout Asia, Australia and North America, is an aquatic perennial that has been cultivated for over 2,000 years. It is very stimulating that almost all parts of lotus have been consumed as vegetable as well as food, especially the seeds. Except for the nutritive values of lotus, there has been increasing interest in its potential as functional food due to its rich secondary metabolites, such as flavonoids and alkaloids. Not only have these metabolites greatly contributed to the biological process of lotus seeds, but also have been reported to possess multiple health-promoting effects, including antioxidant, anti-amnesic, anti-inflammatory, and anti-tumor activities. Thus, comprehensive metabolomic profiling of these metabolites is of key importance to help understand their biological activities, and other chemical biology features. In this context, this review will provide an update on the current technological platforms, and workflow associated with metabolomic studies on lotus seeds, as well as insights into the application of metabolomics for the improvement of food safety and quality, assisting breeding, and promotion of the study of metabolism and pharmacokinetics of lotus seeds; meanwhile it will also help explore new perspectives and outline future challenges in this fast-growing research subject.

Response surface optimization and physicochemical properties of polysaccharides from Nelumbo nucifera leaves

Dynamic high pressure microfluidization (DHPM)-assisted extraction (DHPMAE) of lotus (Nelumbo nucifera) leaves polysaccharides (LLPs) was optimized by response surface methodology. The optimal extraction conditions were: liquid/solid ratio of 35:1 (v/m, mL/g), processing pressure of 180 MPa, processed two times, extraction temperature of 76°C, extraction time of 50 min. Under the optimal extraction conditions, DHPMAE produced a higher polysaccharides yield (6.31%) than leaching (2.95%). Scanning electron microscope (SEM) analysis revealed that DHPM could reduce the particles size and make the surface more unconsolidated. The LLPs prepared by both methods showed similar FT-IR spectrum, and were consisted of the same monosaccharides, including rhamnose, fucose, arabinose, xylose, mannose, glucose and galactose. The content of each monosaccharide in extracts, however, was quite different. The average molecular weight of LLPs prepared by DHPMAE is 550 kDa, smaller than 578 kDa obtained by leaching. The LLPs prepared by DHPMAE exhibited stronger DPPH scavenging ability (IC50 value of 0.38 mg/mL), HO scavenging ability (IC50 value of 0.61 mg/mL) and reducing power. Therefore, DHPMAE can be a promising alternative to traditional extraction techniques for polysaccharides from plants, and lotus leaves might be a potential resource of natural antioxidants.

Lotus (Nelumbo nucifera Gaertn) plumule polysaccharide ameliorates pancreatic islets loss and serum lipid profiles in non-obese diabetic mice

To unravel possible protective effects of a newly isolated lotus plumule polysaccharide (LPPS) on type 1 diabetes (T1D), this study isolated LPPS and administered it to non-obese diabetic (NOD) female mice for 15 weeks. Oral glucose tolerance, serum ketone body, glucose, insulin, and lipid levels, as well as pancreatic islet cell numbers and the insulin secretion ability of the experimental mice were determined. The results showed that LPPS administration in vivo significantly (P<0.05) increased pancreatic islet cell numbers and slightly enhanced the basal insulin secretion ability compared to the control group. LPPS administration improved serum lipid profiles in the diabetic mice via relatively increasing serum high density lipoprotein-cholesterol, but decreasing low density lipoprotein-cholesterol and total cholesterol levels. The present study suggests that LPPS supplementation may ameliorate T1D progress and its complications through protecting pancreatic islets and modulating serum lipid profiles.

Purified active lotus plumule (Nelumbo nucifera Gaertn) polysaccharides exert anti-inflammatory activity through decreasing toll-like receptor-2 and -4 expressions using mouse primary splenocytes

ETHNOPHARMACOLOGICAL SIGNIFICANCE

Lotus plumule is widely used as traditional Chinese medicine. Among the active components in lotus plumule, polysaccharides exhibit promising potential for its potent anti-inflammatory effects. However, the anti-inflammatory mechanism of purified polysaccharides from lotus plumule remains unknown. To evaluate their anti-inflammatory potential and possible mechanisms of purified polysaccharides in lotus plumule, two active lotus plumule polysaccharides, fractions F1 and F2, were subjected to assay their anti-inflammatory potential and possible mechanisms using murine primary splenocytes in the absence or presence of lipopolysaccharide (LPS).

MATERIALS AND METHODS

Two purified active lotus plumule polysaccharides, F1 and F2, were cultured independently with murine primary splenocytes in the absence or presence of LPS under four different experiment models in vitro. Changes in pro-inflammatory IL-1β, IL-6 and TNF-α, as well as anti-inflammatory IL-10 cytokines secreted by the treated splenocytes were determined using an enzyme-linked immunosorbent assay (ELISA). The amount of toll-like receptor (TLR)-2 and TLR-4 mRNA expression levels in the cells were quantitated using a two-step real-time polymerase chain reaction (PCR) assay.

RESULTS

The results showed that F1 and F2 treatments alone, particularly F2, significantly (P<0.05) decreased pro-/anti-inflammatory (IL-1β/IL-10 and TNF-α/IL-10) cytokine secretion ratios dose-dependently. F1 and F2 treatments in the presence of LPS significantly decreased TLR-2 and/or TLR-4 mRNA expression levels in the splenocytes under inflammatory and repair experiment models.

CONCLUSIONS

The present study proved that F1 and F2 had strong anti-inflammatory effects through inhibiting TLR-2 and/or TLR-4 expressions in the splenocytes in normal, inflammatory and repair situations. Our results further suggest that F2, which is a glycoprotein with low molecular weight of 25.7 kDa, may serve as a promising lead for the development of selective TLR antagonistic agents for inflammatory diseases.

Anti-inflammatory and anti-apoptotic effects of strawberry and mulberry fruit polysaccharides on lipopolysaccharide-stimulated macrophages through modulating pro-/anti-inflammatory cytokines secretion and Bcl-2/Bak protein ratio

This study is the first to isolate strawberry (SP) and mulberry fruit polysaccharides (MP) and assess their anti-inflammatory and anti-apoptotic activities using lipopolysaccharide (LPS)-stimulated mouse primary macrophages. Pro-/anti-inflammatory cytokine levels secreted by LPS-stimulated macrophages cultured with SP and MP for 48 h were determined using ELISA method to evaluate anti-inflammatory effects of SP and MP. The Bcl-2/Bak (anti-/pro-apoptotic) protein levels in the cells were determined using Western blotting method to evaluate anti-apoptotic effects of SP and MP. The results showed that the maximum absorption peak of SP and MP appeared at 240 nm with a small shoulder around 280∼310 nm, suggesting that SP and MP might be glycoproteins. SP- and MP-treatment significantly (P<0.05) decreased pro-inflammatory cytokines including interleukin (IL)-1β and IL-6, whereas the anti-inflammatory cytokine IL-10 was markedly increased, suggesting that SP and MP have anti-inflammation potential via modulating pro-/anti-inflammatory cytokine secretion profiles. Both SP and MP modulated Bak and Bcl-2 protein levels in the cells, suggesting that the SP and MP protected LPS-stimulated macrophages from apoptotic cell death. A negative correlation between cytokine secretion levels and Bcl-2 protein levels suggested that pro-inflammatory IL-1β and IL-6 cytokines decreased Bcl-2 levels in the LPS-stimulated macrophages.

Berberine, an isoquinoline alkaloid, inhibits streptozotocin-induced apoptosis in mouse pancreatic islets through down-regulating Bax/Bcl-2 gene expression ratio

Diabetes may cause apoptosis in pancreatic islets. Berberine is an isoquinoline alkaloid used for its pharmacological functions including anti-inflammation. However, the berberine effect on pancreatic islets is still not clear. This study is aimed at clarifying the protective mechanism in berberine against islet cell apoptosis. This study established in vitro experimental models using streptozotocin (STZ)-treated primary pancreatic islet cells from ICR mice to unravel the protective mechanism of berberine on islets. The Bax/Bcl-2 (pro-/anti-apoptotic) genes expression in the islets was determined using real-time quantitative polymerase chain reaction assay. The results showed that berberine administration at one time or before STZ-stimulation significantly (P<0.05) down-regulated the Bax/Bcl-2 genes expression ratio, compared to those in STZ-treatment alone group. Our results suggest that berberine's anti-apoptotic effect on pancreatic primary islets is through down-regulating the Bax/Bcl-2 genes expression ratio in both concurrent and preventive manners.