Prophylactic effects of probiotics on respiratory viruses including COVID-19: a review

Food Science and Biotechnology - Coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is mainly transmitted through respiratory droplets....     

Isolation, partial characterisation and immunomodulatory activities of polysaccharide from Morchella esculenta

BACKGROUND: Polysaccharides extracted from fungi or algae have shown a variety of medical activities, and the exploitation of polysaccharides for application in pharmacy has been very promising. In this study, the immunomodulatory properties of polysaccharides from Morchella esculenta were investigated to identify immunostimulatory activity and potentially contribute to the therapeutic potential of Morchella esculenta. RESULTS: A water‐soluble polysaccharide, MEP, was obtained from the fermentation broth of Morchella esculenta. Two fractions of this polysaccharide (MEP‐I and MEP‐II) were extracted and purified. High‐performance gel permeation chromatography analysis showed the average molecular weights of two polysaccharides. Structural properties and compositions of these two fractions were examined by Fourier transform infrared and a high‐performance liquid chromatography with an evaporative light scattering detector. Active experiments suggested that the MEP had typical immunostimulatory activity. CONCLUSION: These bioactivity tests showed that the polysaccharides from Morchella esculenta presented significant immune modulating activity, and this finding may offer the basis for the popular use of polysaccharides in functional foods or medicine. Copyright © 2011 Society of Chemical Industry     

蛹虫草免疫调节蛋白分离纯化、结构表征与免疫调节活性研究

目的 探究蛹虫草蛋白质的免疫调节活性和一级结构。方法 过碱溶酸沉法提取蛹虫草蛋白质,并且用阴离子交换层析法和葡聚糖凝胶层析法对其进行分离纯化,获得一种免疫调节效果较好的组分(记为CMP 2b),通过建立小鼠巨噬细胞免疫调节模型对其组分进行活性评价得到活性最佳的组分,通过基质辅助激光解吸飞行时间质谱测得其分子量大小,通过蛋白质谱解析出其蛋白质一级结构。通过小鼠巨噬细胞研究其对巨噬细胞RAW264.7增殖活性、吞噬率、一氧化氮(nitrogen monoxide, NO)分泌量、免疫因子白细胞介素-1β (interleukin-1β, IL-1β)、免疫因子白细胞介素-6 (interleukin-6, IL-6)、干扰素-γ (Interferon-γ,IFN-γ)和肿瘤坏死因子-α (tumor necrosis factor-α, TNF-α)释放量等方面。结果 通过阴离子交换色谱和葡聚糖凝胶色谱分离纯化出一种蛹虫草免疫调节蛋白CMP 2b,由蛋白质谱测得它由196个氨基酸组成,分子量为22.460 kDa;通过建立巨噬细胞免疫调节模型,研究得出CMP 2b对巨噬细胞的增殖能力、吞噬能能力有显著提高,细胞增殖率最高达到了空白对照组的152.91±5.55%,吞噬能力提高了23.34%;并且促进巨噬细胞分泌NO、ROS、IL-1β、IL-6、IFN-γ及TNF-α,其中NO分泌水平分别达到了空白对照组的2.31倍,ROS 分泌水平达到阳性对照组 LPS的 82.33%,TNF-α、IL-1β、IFN-γ和IL-6分泌量分别为空白对照组的5.51倍、17.42 倍、4.18倍和26.75 倍,显著增强了巨噬细胞免疫调节能力。     

基于大鼠血清差异蛋白质组学小白杏杏仁油免疫调节作用研究

采用i TRAQ标记及高效液相色谱-电喷雾串联质谱(LC-ESI-MS/MS)技术对小白杏杏仁油干预试验大鼠血清差异表达蛋白进行定量鉴定,并通过表达模式及代谢通路聚类对鉴定获得的差异蛋白进行生化代谢途径和信号转导途径分析。结果表明,小白杏杏仁油可能通过调节血清中结合珠蛋白(HP)、角蛋白(KRT10、KRT42)、微管蛋白α-8链(TUBA8)、免疫球蛋白重(k)链VⅢ区(VH26、MOPC63)、α-1-抗蛋白酶(SERPINA1)及T-激肽原(KNG1)等蛋白的表达水平,作用于金黄色葡萄球菌感染、吞噬体、致病性大肠杆菌感染、原发性免疫缺陷、补体和凝血级联5条先天性免疫通路而展现其免疫调节作用。     

Intestinal microbiota are involved in the immunomodulatory activities of longan polysaccharide

It is difficult for polysaccharides to be directly absorbed through the intestine, which implies other utilization mechanisms involved in the bioactivity performance of polysaccharide. In this study, the multi‐omics approach was applied to investigate the impacts of longan polysaccharide on mouse intestinal microbiome and the interaction between the polysaccharide‐derived microbiome and host immune system. According to the result, the longan polysaccharide showed a significant improvement in the typical intestinal immunity index of mice. Meanwhile, at the taxonomy level, the intestinal microbiota from the control group and polysaccharide group were highly distinct in organismal structure. At the functional level, a significant decline in the microbial metabolites of pyruvate, butanoate fructose and mannose in the control group was found. Additionally, a significant increase was observed in the succinic acid and the short‐chain fatty acid, including acetic acid, propionic acid and butyric acid, in the polysaccharide group. Furthermore, the multi‐omic based network analysis indicated that the intake of longan polysaccharide resulted in the changes of the intestinal microbiota as well as the gut metabolites, which led to the enhancement of host's immune function under the stress conditions. These results indicated the polysaccharide‐derived changes in intestinal microbiota were involved in the immunomodulatory activities.     

Immunomodulatory and anticancer activities of phenolics from emblica fruit (Phyllanthus emblica L.)

There is a paucity of studies on the immunomodulatory properties of fruit extracts of emblica with the emphasis on lymphocytes. Therefore, the aim of the study was to evaluate the immunomodulatory properties and anticancer potential of six phenolic compounds from emblica fruit by in vitro proliferation assay. Effects of these compounds on splenocyte proliferation and the cytotoxicity to both human breast cancer cell (MCF-7) and human embryonic lung fibroblast cell (HELF) were determined by the MTT method. Significantly stimulatory effects (P < 0.05) were found for geraniin and isocorilagin. The concentration of geraniin, quercetin 3-β-d-glucopyranoside, kaempferol 3-β-d-glucopyranoside, isocorilagin, quercetin, kaempferol and rutin to obtain 50% of stimulatory effect was 56, 123, 242, 42, 73, 93 and 92 μg/ml, respectively. The assay of anticancer activities suggested that geraniin and isocorilagin exhibited higher cytotoxicities than other compounds against MCF-7 with IC₅₀ of 13.2 and 80.9 μg/ml, respectively. Isocorilagin exhibited a strong cytotoxicity to HELF cell with IC₅₀ of 51.4 μg/ml. Geraniin, quercetin, kaempferol and their glycosides had weak cytotoxicity against HELF cells. Paclitaxel showed a strong cytotoxicity to MCF-7 and HELF with IC₅₀ of 6.8 and 14.5 μg/ml, respectively. These findings are in line with the reported potent antioxidant activity. These results suggested that the antitumour activity of these compounds might be achieved by immunomodulatory properties which could partially be attributed to their antioxidant activity.     

Effects of orally administered yeast‐derived beta‐glucans: A review

Yeast‐derived beta‐glucans (Y‐BG) are considered immunomodulatory compounds suggested to enhance the defense against infections and exert anticarcinogenic effects. Specific preparations have received Generally Recognized as Safe status and acceptance as novel food ingredients by European Food Safety Authority. In human trials, orally administered Y‐BG significantly reduced the incidence of upper respiratory tract infections in individuals susceptible to upper respiratory tract infections, whereas significant differences were not seen in healthy individuals. Increased salivary IgA in healthy individuals, increased IL‐10 levels in obese subjects, beneficial changes in immunological parameters in allergic patients, and activated monocytes in cancer patients have been reported following Y‐BG intake. The studies were conducted with different doses (7.5–1500 mg/day), using different preparations that vary in their primary structure, molecular weight, and solubility. In animal models, oral Y‐BG have reduced the incidence of bacterial infections and levels of stress‐induced cytokines and enhanced antineoplastic effects of cytotoxic agents. Protective effects toward drug intoxication and ischemia/reperfusion injury have also been reported. In conclusion, additional studies following good clinical practice principles are needed in which well‐defined Y‐BG preparations are used and immune markers and disease endpoints are assessed. Since optimal dosing may depend on preparation characteristics, dose‐response curves might be assessed to find the optimal dose for a specific preparation.     

Purification, antitumour and immunomodulatory activity of water-extractable and alkali-extractable polysaccharides from Solanum nigrum L.

The water-extractable and the alkali-extractable polysaccharides from Solanum nigrum L. (named SNLWP and SNLAP, respectively) and their four polysaccharide sub-fractions (SNLWP-1, SNLWP-2, SNLAP-1 and SNLAP-2), were isolated and purified by ethanol precipitation, dialysis, anion-exchange and gel filtration chromatography. Antitumour and immunomodulatory activity of the polysaccharides was evaluated by determining the survival time, the ascites volume, the weight of immune organ and the level of cytokine (IL-2, IL-10 and IFN-γ) of H₂₂-bearing mice, respectively. The results showed that SNLWP-1, SNLAP-1 and SNLAP-2 had significant antitumour and immunomodulatory activity, whereas SNLWP-2 hardly demonstrated the activity. SNLWP-1 contained galactose and arabinose as main sugar components, and both SNLAP-1 and SNLAP-2 were rich in xylose, galactose and arabinose. SNLWP-2 was rich in glucose. In conclusion, SNLWP-1, SNLAP-1 and SNLAP-2 have potent antitumour activity which may be associated with their potent immunostimulating effect and monosaccharide composition.     

Immunomodulation by hydrolysates and peptides derived from milk proteins

Milk protein‐derived peptides have shown immunomodulatory properties either singly or in a mixture. However, information on the behaviour of these compounds is scarce, complicating their further study. This review presents current knowledge on immunomodulatory milk protein‐derived peptides, including hydrolysates, peptide fractions and single peptides. The evidence shows that hydrolysates derived from both casein and whey proteins show immunomodulatory effects; however, this bioactivity is mainly attributed to peptides derived from caseins. The identification of peptides in hydrolysates, as well as their characterisation and knowledge of the mechanisms behind their bioactivity, is necessary to further exploit their potential health benefits.     

Antioxidant and immunomodulatory activity of selenium exopolysaccharide produced by Lactococcus lactis subsp. lactis

Exopolysaccharide (EPS) was isolated and purified from Lactococcus lactis subsp. Lactis culture broth. Selenium chloride oxide (SeCl₂O) was added to the EPS to synthesize selenium-exopolysaccharide (Se-EPS). The in vitro and in vivo antioxidant and in vivo immunomodulatory activity of EPS and Se-EPS were compared. EPS and Se-EPS scavenged superoxide anions and hydroxyl radicals. They also increased catalase (CAT), superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activity, while decreasing malondialdehyde (MDA) levels in serum and in the livers of mice. Se-EPS showed stronger in vitro and in vivo antioxidant activity than were shown by EPS. The in vivo immunoenhancement activity of EPS and Se-EPS induced by cyclophosphamide (CY) treatment in immunosuppressed mice was researched. EPS and Se-EPS treatments increased macrophage phagocytosis, spleen and thymus indices and haemolytic complement activity (HC₅₀). Se-EPS showed stronger immunomodulatory activity than did EPS.