Lectins are non-immunological carbohydrate-binding proteins classified on the basis of their structure, origin, and sugar specificity. The binding specificity of such proteins with the surface glycan moiety determines their activity and clinical applications. Thus, lectins hold great potential as diagnostic and drug discovery agents and as novel biopharmaceutical products. In recent years, significant advancements have been made in understanding plant and microbial lectins as therapeutic agents against various viral diseases. Among them, mannose-specific lectins have being proven as promising antiviral agents against a variety of viruses, such as HIV, Influenza, Herpes, Ebola, Hepatitis, Severe Acute Respiratory Syndrome Coronavirus-1 (SARS-CoV-1), Middle Eastern Respiratory Syndrome Coronavirus (MERS-CoV) and most recent Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2). The binding of mannose-binding lectins (MBLs) from plants and microbes to high-mannose containing N-glycans (which may be simple or complex) of glycoproteins found on the surface of viruses has been found to be highly specific and mainly responsible for their antiviral activity. MBLs target various steps in the viral life cycle, including viral attachment, entry and replication. The present review discusses the brief classification and structure of lectins along with antiviral activity of various mannose-specific lectins from plants and microbial sources and their diagnostic and therapeutic applications against viral diseases.

Crataegus, is a genus within the Rosaceae family. It is recognized as a valuable plant with both medicinal and edible qualities, earning it the epithet of the \"nutritious fruit\" owing to its abundant bioactive compounds. Polysaccharides are carbohydrate polymers linked by glycosidic bonds, one of the crucial bioactive ingredients of Crataegus spp. Recently, Crataegus spp. polysaccharides (CPs) have garnered considerable attention due to their diverse range of bioactivities, including prebiotic, hypolipidemic, anticancer, antibacterial, antioxidant, and immunobiological properties. Herein, we provide a comprehensive overview of recent research on CPs. The analysis revealed that CPs exhibited a broad molecular weight distribution, ranging from 5.70 Da to 4.76 × 108 Da, and are composed of various monosaccharide constituents such as mannose, rhamnose, and arabinose. Structure-activity relationships demonstrated that the biological function of CPs is closely associated with their molecular weight, galacturonic acid content, and chemical modifications. Additionally, CPs have excellent bioavailability, biocompatibility, and biodegradability, which make them promising candidates for applications in the food, medicine, and cosmetic industries. The article also scrutinized the potential development and future research directions of CPs. Overall, this article provides comprehensive knowledge and underpinnings of CPs for future research and development as therapeutic agents and multifunctional food additives.

Mannose phosphate isomerase-congenital disorder of glycosylation (MPI-CDG) is a CDG presenting with a clinically recognizable presentation, including early hypoglycemia, coagulation defects, and gastrointestinal and hepatic symptoms. We report on a female patient with biallelic pathogenic mutations in the MPI gene who presented with recurrent respiratory infections and abnormal IgM levels, but none of the classic symptoms associated with MPI-CDG. Oral mannose therapy led to a fast improvement in serum IgM levels and transferrin glycosylation in our patient. The patient did not experience severe infections after the initiation of treatment. We also reviewed the immune phenotype in patients so far reported with MPI-CDG.
Using a type of sugar called mannose to strengthen the immune system of a person living with a rare disease called MPI-congenital disorder of glycosylation Mannose phosphate isomerase–congenital disorder of glycosylation (MPI-CDG for short) is a rare, inherited disease that mainly affects the liver and digestive system. People with MPI-CDG typically develop signs and symptoms of the condition during childhood. Common symptoms of MPI-CDG include low blood sugar, blood clotting problems, poor growth, low weight, swelling of the lower legs or hands, digestive problems, and liver problems. Early diagnosis is crucial for people with MPI-CDG, as it is a potentially life-threatening, but treatable disease. Given that there are a small number of people with MPI-CDG, especially those with symptoms related to their immune system, it is important to highlight specific cases to raise awareness. This article summarizes a specific case study of a female child with MPI-CDG. This individual did not experience the usual signs and symptoms of the disease. However, she had multiple infections affecting her respiratory tract, and had abnormal levels of antibodies in her blood. The patient was treated with mannose, a type of sugar that is related to fructose and glucose. After 12 months of treatment, levels of antibodies stabilized. Furthermore, she did not experience any more severe infections after starting treatment with mannose. Tests designed to measure levels of glycosylation, called glycosylation transferrin testing, showed improvement in glycosylation to almost normal levels. In conclusion, this case report adds to the current knowledge about the disease and raises awareness that patients can present with immunological problems. It also shows that mannose treatment can be an effective treatment to improve the immune system and glycosylation in MPI-CDG.

Unmodified nanocarriers used in the chemotherapy of cancers and various infectious diseases exhibit prolonged blood circulation time, prevent enzymatic degradation and increase chemical stability of encapsulated therapeutics. However, off-target effect and lack of specificity associated with unmodified nanoparticles (NPs) limit their applications in the health care system. Mannose (Man) receptors with significant overexpression on antigen-presenting cells and macrophages are among the most admired targets for cancer and anti-infective therapeutics. Therefore, development of Man functionalized nanocarriers targeting Man receptors, for target specific drug delivery in the chemotherapy have been extensively studied. Present review expounds diverse Man-conjugated NPs with their potential for targeted drug delivery, improved biodistribution profiles and localization. Additionally, the review gives detailed account of the interactions of mannosylated NPs with various biological systems and their characterization not discussed in earlier published reports is discussed.

The use of antibiotics in the treatment of UTIs is contributing to resistance. Hence, the outcome of human clinical trials of nonantibiotic remedies for preventing or treating UTI is of significant interest. This systematic review aimed to identify, summarise and evaluate the evidence for the outcomes of different nonantibiotic options including cranberry, D-mannose and non-steroidal anti-inflammatory drugs (NSAIDs). PubMed, Embase and Scopus were searched for manuscripts relating to nonantibiotic treatment of UTI including cranberry, mannose and NSAIDs. After title and abstract screening, data were extracted from 21 papers that were published in English and related to the treatment or prevention of uncomplicated UTI in adult women. We identified twelve papers examining the effects of cranberry, two papers examining D-mannose, two papers examining combination treatments (cranberry and D-mannose) and five manuscripts investigating the effects of NSAIDs. There is low-level evidence, from a small number of studies, supporting the use of D-mannose or combination treatments for potentially preventing UTIs in adult women without producing burdening side effects. However, larger and more randomised double-blinded trials are needed to confirm this. In comparison, the multiple studies of cranberry and NSAIDs produced conflicting evidence regarding their effectiveness.

Galactomannans are reserve carbohydrates in legume plants and are primarily extracted from their seeds. They contain galactose side chains throughout the mannose backbone and have unique features such as emulsifying, thickening, and gelling together with biodegradability, biocompatibility, and non-toxicity, which make them an appealing material. Guar gum and locust bean gum mainly are used in all galactomannan needed applications. Nonetheless, tara gum and fenugreek gum have also attracted considerable attention in recent decades. Despite the increased usage of galactomannans in the textile-related fields in recent years, there is no review article published yet. To fill this gap and to demonstrate the striking and increasing importance of galactomannans, a concise summary of the properties of common galactomannans and their comparisons is given first, followed by an account of recent developments and applications of galactomannans in the textile-related fields. The associated potential opportunities are also provided at the end of this review.

Urinary tract infections (UTIs) are one of the most prevalent bacterial diseases worldwide. Despite the efficacy of antibiotics targeted against UTI, the recurrence rates remain significant among the patients. Furthermore, the development of antibiotic resistance is a major concern and creates a demand for alternative treatment options. D-mannose, a monosaccharide naturally found in fruits, is commonly marketed as a dietary supplement for reducing the risk for UTIs. Research suggests that supplemented D-mannose could be a promising alternative or complementary remedy especially as a prophylaxis for recurrent UTIs. When excreted in urine, D-mannose potentially inhibits Escherichia coli, the main causative organism of UTIs, from attaching to urothelium and causing infection. In this review, we provide an overview of UTIs, E. coli pathogenesis and D-mannose and outline the existing clinical evidence of D-mannose in reducing the risk of UTI and its recurrence. Furthermore, we discuss the potential effect mechanisms of D-mannose against uropathogenic E.coli.

MPI-CDG is a rare congenital disorder of glycosylation (CDG) which presents with hepato-gastrointestinal symptoms and hypoglycemia. We report on hepatic evaluation of two pediatric patients who presented to us with gastrointestinal symptoms. Analysis of carbohydrate deficient transferrin (CDT) showed a Type 1 pattern and molecular analysis confirmed the diagnosis of MPI-CDG. Oral mannose therapy was markedly effective in one patient but was only partially effective in the other who showed progressive portal hypertension.

We performed a systematic review and meta-analysis to determine whether D-mannose reduces urinary tract infection recurrence (ie, cumulative incidence) in adult women with recurrent urinary tract infection compared with other prevention agents. Secondary outcomes included side effects and compliance with D-mannose use.
Ovid Medline 1946-, Embase 1947-, Scopus 1823-, Cochrane Library, Web of Science 1900-, and ClinicalTrials.gov were searched through 4/15/2020.
Systematic review inclusion: randomized controlled trials, prospective cohorts, and retrospective cohorts written in English of women ≥18 years old with recurrent urinary tract infection in which D-mannose was utilized as an outpatient prevention regimen. Systematic review exclusion: lab or animal-based research, study protocols only, and conference abstracts. Meta-analysis inclusion: stated D-mannose dose, follow-up time ≥6 months, a comparison arm to D-mannose, and data available from women ≥18 years of age.
Two independent reviewers made abstract, full text, and data extraction decisions. Study methodologic quality was assessed using the Cochrane Risk of Bias tool. Relative risks, confidence intervals, and heterogeneity were computed.
Searches identified 776 unique citations. Eight publications met eligibility: 2 using D-mannose only; 6 using D-mannose combined with another treatment. Seven studies were prospective: 2 randomized controlled trials, 1 randomized cross-over trial, and 4 prospective cohort studies. One retrospective cohort study was included. Three studies met meta-analysis eligibility (1 randomized controlled trial, 1 randomized cross-over trial, and 1 prospective cohort). Pooled relative risk of urinary tract infection recurrence comparing D-mannose to placebo was 0.23 (95% confidence interval, 0.14-0.37; heterogeneity=0%; D-mannose n=125, placebo n=123). Pooled relative risk of urinary tract infection recurrence comparing D-mannose to preventative antibiotics was 0.39 (95% confidence interval, 0.12-1.25; heterogeneity=88%; D-mannose n=163, antibiotics n=163). Adverse side effects were reported in 2 studies assessing D-mannose only (1 study (n=10) reported none; the other reported a low incidence (8/103 participants) of diarrhea). Two studies reported compliance, which was high.
D-mannose appears protective for recurrent urinary tract infection (vs placebo) with possibly similar effectiveness as antibiotics. Overall, D-mannose appears well tolerated with minimal side effects-only a small percentage experiencing diarrhea. Meta-analysis interpretation must consider the small number of studies with varied study design and quality and the overall small sample size.

The non-modified nanocarriers-based therapies for the treatment of cancer and other infectious diseases enhanced the chemical stability of therapeutically active agents, protected them from enzymatic degradation and extended their blood circulation time. However, the lack of specificity and off-target effects limit their applications. Mannose receptors overexpressed on antigen presenting cells such as dendritic cells and macrophages are one of the most desirable targets for treating cancer and other infectious diseases. Therefore, the development of mannosylated nanocarrier formulation is one of the most extensively explored approaches for targeting these mannose receptors. The present manuscript gives readers the background information on C-type lectin receptors followed by the roles, expression, and distribution of the mannose receptors. It further provides a detailed account of different mannosylated nanocarrier formulations. It also gives the tabular information on most relevant and recently granted patents on mannosylated systems. The overview of mannosylated nanocarrier formulations depicted site-specific targeting, enhanced pharmacokinetic/pharmacodynamic profiles, and improved transfection efficiency of the therapeutically active agents. This suggests the bright future ahead for mannosylated nanocarriers in the treatment of cancer and other infectious diseases. Nevertheless, the mechanism behind the enhanced immune response by mannosylated nanocarriers and their thorough clinical and preclinical evaluation need to explore further.