To date, a number of mannose-binding lectins have been isolated and characterized from plants and fungi. These proteins are composed of different structural scaffold structures which harbor a single or multiple carbohydrate-binding sites involved in the specific recognition of mannose-containing glycans. Generally, the mannose-binding site consists of a small, central, carbohydrate-binding pocket responsible for the "broad sugar-binding specificity" toward a single mannose molecule, surrounded by a more extended binding area responsible for the specific recognition of larger mannose-containing N-glycan chains. Accordingly, the mannose-binding specificity of the so-called mannose-binding lectins towards complex mannose-containing N-glycans depends largely on the topography of their mannose-binding site(s). This structure⁻function relationship introduces a high degree of specificity in the apparently homogeneous group of mannose-binding lectins, with respect to the specific recognition of high-mannose and complex N-glycans. Because of the high specificity towards mannose these lectins are valuable tools for deciphering and characterizing the complex mannose-containing glycans that decorate both normal and transformed cells, e.g., the altered high-mannose N-glycans that often occur at the surface of various cancer cells.

https://hal-amu.archives-ouvertes.fr/hal-02388775/document

Overview of the Structure–Function Relationships of Mannose-Specific Lectins from Plants, Algae and Fungi

Current challenges to antiretroviral therapy have opened new vistas in the search for novel drugs from natural products. This review focusses on plants as sources of inhibitors for human immunodeficiency virus type 1 (HIV-1) reverse transcriptase. Based on a systematic search of the literature, anti-HIV-1 reverse transcriptase activity was recorded for 132 plant species in 100 genera and 51 families. Seven families comprise 52.6% of plant species with anti-reverse transcriptase activity: Lamiaceae (13.7%), Fabaceae (10.7%), Euphorbiaceae (9.9%), Clusiaceae (6.1%), Asteraceae (4.6%), Combretaceae (4.6%), and Moraceae (3.0%). The repertoire of anti-reverse transcriptase active compounds includes (-)-catechin, 1,8-cineole, 3,4-di-O-caffeoylquinic acid, 5,7-dimethoxy-6-methylflavone, apigenin, baicalein, betulinic acid, caffeic acid, cis-3-hexene-1-ol, eugenol, euscaphic acid, gallic acid, hoslunddiol, limonene, naringenin, oleanolic acid, p-cymene, pomolic acid, quinic acid, rosmarinic acid, stigmasterol, thymol, ursolic acid, α-bergamotene, α-pinene, and γ-terpinene. Among the IC50 values are 0.10 μg/ml (Uvaria angolensis), 3 μg/ml (Hemidesmus indicus), 2. 3μg/ml (Adansonia digitata), 6.24 μg/ml (Caesalpinia coriaria), 7.2 μg/ml (Terminalia sericea), 17.4 μg/ml (Hypoxis hemerocallidea), and 79 μg/ml (Moringa oleifera). The chemical diversity and activity profiles of HIV-1 reverse transcriptase inhibitors from plants reveal two recurring motifs: the structure of several active anti-reverse transcriptase compounds mimics nucleoside analogues, and numerous anti-reverse transcriptase phytochemicals have pleiotropic effects and heterogenous pharmacological benefits during infection and disease. To accelerate drug discovery and development, this review recommends the urgent need to tap into the rich vein of indigenous knowledge of putative anti-HIV/AIDS medicinal plants (reverse pharmacology), determine pan-assay interference compounds, analyze structure-activity relationships, and conduct more clinical trials.

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Chemical diversity and activity profiles of HIV-1 reverse transcriptase inhibitors from plants

Dioscorea species, known as "Yams," belong to family Dioscoreaceae. This genus consists of more than 600 species distributed from Africa, Asia, the Caribbean's South America, and the South Pacific islands. Their organoleptic properties make them the most widely used carbohydrate food and dietary supplements. The underground and/or aerial tubers represent valuable sources of proteins, fats, and vitamins for millions of people in West Africa. This review gives a shot of secondary metabolites of Dioscorea plants, including steroids, clerodane diterpenes, quinones, cyanidins, phenolics, diarylheptanoids, and nitrogen-containing compounds. This review collected the evidence on biological properties of description Dioscorea, including in-vitro and in-vivo studies. Dioscorea species contain promising bioactive molecules i.e. diosgenin that support their different biological properties, including antioxidant, hypoglycaemic, hypolipidemic, anti- antimicrobial, inflammatory, antiproliferative, androgenic, estrogenic, and contraceptive drugs. Indeed, besides its nutrient values, Dioscorea is a potential source of bioactive substances of interest in the prevention/treatment of several diseases, and thus represents a great challenge in developing countries. However, ethnomedicinal potential should be validated and further researches on pharmacological properties and phytochemical composition should be carried out. Particularly, doing some studies to convert the preclinical results to clinical efficacy should be guaranteed. Dioscorea, Food plant, Traditional use, Phytochemistry, Pharmacological activities.

http://ijpr.sbmu.ac.ir/article_1100987_1897b6db9e9b87efd827dc147f6a771a.pdf

Dioscorea Plants: A Genus Rich in Vital Nutra-pharmaceuticals-A Review.

Seed storage proteins play a fundamental role in plant reproduction and human nutrition. They accumulate during seed development as reserve material for germination and seedling growth and are a major source of dietary protein for human consumption. Storage proteins encompass multiple isoforms encoded by multi-gene families that undergo abundant glycosylations and phosphorylations. Two-dimensional electrophoresis (2-DE) is a proteomic tool especially suitable for the characterization of storage proteins because of their peculiar characteristics. In particular, storage proteins are soluble multimeric proteins highly represented in the seed proteome that contain polypeptides of molecular mass between 10 and 130 kDa. In addition, high-resolution profiles can be achieved by applying targeted 2-DE protocols. 2-DE coupled with mass spectrometry (MS) has traditionally been the methodology of choice in numerous studies on the biology of storage proteins in a wide diversity of plants. 2-DE-based reference maps have decisively contributed to the current state of our knowledge about storage proteins in multiple key aspects, including identification of isoforms and quantification of their relative abundance, identification of phosphorylated isoforms and assessment of their phosphorylation status, and dynamic changes of isoforms during seed development and germination both qualitatively and quantitatively. These advances have translated into relevant information about meaningful traits in seed breeding such as protein quality, longevity, gluten and allergen content, stress response and antifungal, antibacterial, and insect susceptibility. This review addresses progress on the biology of storage proteins and application areas in seed breeding using 2-DE-based maps.

https://www.mdpi.com/1420-3049/23/10/2462/pdf

Advances in the Biology of Seed and Vegetative Storage Proteins Based on Two-Dimensional Electrophoresis Coupled to Mass Spectrometry

Biochemical characterisation of lectin from Indian hyacinth plant bulbs with potential inhibitory action against human cancer cells

Purification, characterization and biological significance of mannose binding lectin from Dioscorea bulbifera bulbils

Sclerotium rolfsii lectin (SRL) is a lectin isolated from the fungus Sclerotium rolfsii and has exquisite binding specificity towards the oncofetal Thomsen-Friedenreich antigen (TF-Ag; Galβ1-3GalNAcα-O-Ser/Thr) and its derivatives. Previous studies have shown that SRL inhibits the proliferation of human colon, breast and ovarian cancer cells in vitro and suppresses tumour growth in mice when introduced intratumourally. The present study assessed the effect of SRL on tumour growth when introduced intraperitoneally in BALB/c nude mice and investigated the pharmacokinetics and biodistribution of SRL in Swiss albino mice. When 9 doses of SRL (30 mg/kg body weight/mice) was administered to BALB/c nude mice bearing human colon cancer HT-29 xenografts, a substantial reduction in tumour size was observed. A 35.8% reduction in tumour size was noted in the treated animals after 17 days. SRL treatment also inhibited angiogenesis, and the tumours from the treated animals were observed to carry fewer blood vessels and express less angiogenesis marker protein CD31, than that from the control animals. Pharmacokinetics and biodistribution analysis revealed that SRL was detected in the serum after 1 h and its level peaked after 24 h. SRL was not detected in any of the organs apart from the kidney where a trace amount was detected after 24 h of SRL injection. No significant changes were observed in any of the biochemical parameters tested including SGOT, SGPT, LDH, CREAT and BUN in the SRL-treated mice compared to these levels in the controls. This suggests that SRL has good potential to be developed as a therapeutic agent for cancer treatment and warrant further investigations in vivo and subsequent clinical trials.

/pdf/pharmacokinetics-biodistribution-and-antitumour-effects-of-hte7totgeu.pdf

Pharmacokinetics, biodistribution and antitumour effects of Sclerotium rolfsii lectin in mice

Plant lectins are gaining interest because of their interesting biological properties. Several Adenia species, that are being used in traditional medicine to treat many health ailments have shown presence of lectins or carbohydrate binding proteins. Here, we report the purification, characterization and biological significance of N-Acetyl galactosamine specific lectin from Adenia hondala (AHL) from Passifloraceae family. AHL was purified in a single step by affinity chromatography on asialofetuin Sepharose 4B column, characterized and its fine sugar specificity determined by glycan array analysis. AHL is human blood group non specific and also agglutinates rabbit erythrocytes. AHL is a glycoprotein with 12.5% of the carbohydrate, SDS-PAGE, MALDI-TOF-MS and ESI-MS analysis showed that AHL is a monomer of 31.6 kDa. AHL is devoid of DNase activity unlike other Ribosome inactivating proteins (RIPs). Glycan array analysis of AHL revealed its highest affinity for terminal lactosamine or polylactosamine of N- glycans, known to be over expressed in hepatocellular carcinoma and colon cancer. AHL showed strong binding to human hepatocellular carcinoma HepG2 cells with MFI of 59.1 expressing these glycans which was effectively blocked by 93.1% by asialofetuin. AHL showed dose and time dependent growth inhibitory effects on HepG2 cells with IC50 of 4.8 μg/ml. AHL can be explored for its clinical potential.

Purification, characterization and fine sugar specificity of a N-Acetylgalactosamine specific lectin from Adenia hondala

Butea monosperma is a medicinal plant extensively used in ayurveda and is known for its medicinal applications. Butea monosperma seed powder is used for treating various health ailments including cancer. Although, most parts of the plant are being used in medicine none of them except for seeds are known to contain lectins. A lectin from seeds has been reported earlier, however it was not tested for its anticancer properties. Since plant lectins are known for their anticancer properties, in order to explore anticancer potential of B. monosperma a legume lectin was purified from seeds in a single step by nine fold, by a modified method using affinity chromatography on lactose-Sepharose 4B column and tested for its anticancer properties against human hepatocellular carcinoma cells. SDS PAGE of BML reveals two bands with Mr of 32 and 34 kDa and a minor band of 67 kDa similar to earlier reported BML. Hapten inhibition assay shows that lectin is specific to GalNAc, galactose, lactose and D-Fucose. BML shows strong binding to Hep G2 cells with MFI of 476. MTT assay showed growth inhibitory effect on Hep G2 cells by BML, PTL1 and PTL2 in a dose and time dependent manner. Growth inhibitory effect of BML on Hep G2 cells was compared with two legume lectins, PTL1 and PTL2 from Psophocarpus tetragonolobus of Fabaceae Family. BML, PTL1 and PTL2 showed growth inhibitory effect on Hep G2 cells. The presence of lectin, in B. monosperma seeds contribute for its anticancer properties.

A modified method for purification of N-acetylgalactosamine specific lectin from Butea monosperma seeds and its effect on human hepatocellular carcinoma cell growth

Mamta Sharma

Papers

Purification, characterization and biological significance of mannose binding lectin from Dioscorea bulbifera bulbils

Pharmacokinetics, biodistribution and antitumour effects of Sclerotium rolfsii lectin in mice

Purification, characterization and fine sugar specificity of a N-Acetylgalactosamine specific lectin from Adenia hondala

A modified method for purification of N-acetylgalactosamine specific lectin from Butea monosperma seeds and its effect on human hepatocellular carcinoma cell growth