Significant differences in function have been observed among lectins structurally similar to concanavalin A, but their high homology with this widely used lectin has kept them in obscurity. The observation of large differences in the potency of many of these Diocleinae lectins as stimulators of Interferon-g production by human peripheral blood mononuclear cells has lead to a major effort to unravel their chemical structure and biological activity. Modeling studies of some of these lectins reveal conformational changes in side chains of some residues involved in the carbohydrate-binding site, with possible effects on the ability of these proteins to recognize specific carbohydrate structures. Additionally, all them constitute in fact a mixture of isolectins, which in different proportions could lead to diverse effects. The present review of the biological actions of Diocleinae lectins includes several in vitro and in vivo immunological findings, as well as their effects on insect growth and reproduction. In these systems Diocleinae lectins proved to be quite diverse in their potency. Such diversity in the biological activity of highly related proteins recalls the origin of the name protein: like Proteus, the capability of assuming various forms is the essential feature of this class of molecules.

Isothermal titration microcalorimetry (ITC) and hemagglutination inhibition measurements demonstrate that a chemically and enzymatically prepared form of porcine submaxillary mucin that possesses a molecular mass of approximately 10(6) daltons and approximately 2300 alpha-GalNAc residues (Tn-PSM) binds to the soybean agglutinin (SBA) with a K(d) of 0.2 nm, which is approximately 10(6)-fold enhanced affinity relative to GalNAcalpha1-O-Ser (Tn), the pancarcinoma carbohydrate antigen. The enzymatically derived 81 amino acid tandem repeat domain of Tn-PSM containing approximately 23 alpha-GalNAc residues binds with approximately 10(3)-fold enhanced affinity, while the enzymatically derived 38/40 amino acid cleavage product(s) of Tn-PSM containing approximately 11-12 alpha-GalNAc residues shows approximately 10(2)-fold enhanced affinity. A natural carbohydrate decorated form of PSM (Fd-PSM) containing 40% of the core 1 blood group type A tetrasaccharide, and 58% peptide-linked GalNAcalpha1-O-Ser/Thr residues, with 45% of the peptide-linked alpha-GalNAc residues linked alpha-(2,6) to N-glycolylneuraminic acid, shows approximately 10(4) enhanced affinity for SBA. Vatairea macrocarpa lectin (VML), which is also a GalNAc binding lectin, displays a similar pattern of binding to the four forms of PSM, although there are quantitative differences in its affinities as compared with SBA. The higher affinities of SBA and VML for Tn-PSM relative to Fd-PSM indicate the importance of carbohydrate composition and epitope density of mucins on their affinities for lectins. The higher affinities of SBA and VML for Tn-PSM relative to its two shorter chain analogs demonstrate that the length of a mucin polypeptide and hence total carbohydrate valence determines the affinities of the three Tn-PSM analogs. The results suggest a binding model in which lectin molecules "bind and jump" from alpha-GalNAc residue to alpha-GalNAc residue along the polypeptide chain of Tn-PSM before dissociating. The complete thermodynamic binding parameters for these mucins including their binding stoichiometries are presented. The results have important implications for the biological activities of mucins including those expressing the Tn cancer antigen.

The present study has evaluated the effects of power ultrasound pre-treatment on air-drying and bioactive compounds of cashew apple bagasse. The sonication induced the disruption of cashew bagasse parenchyma, which resulted in lower resistance to water diffusion, less hysteresis, and increased rehydration rate. The processing did not affect the lignocellulose fibers or the sclerenchyma cells. For sonicated samples, water activity reached values below 0.4, after 2h of drying, which is appropriate to prevent bacterial and fungi growth. The sorption isotherms of cashew apple bagasse presented sigmoid-shape for all samples and followed the type II according to BET classification. Sonicated cashew apple bagasse showed higher antioxidant activity, higher total phenolic compounds (TPC) and higher vitamin C content when compared to the non-sonicated sample. The increase in TPC and vitamin C contributed to the product antioxidant activity. A slight reduction on Vitamin C bioaccessibility was observed, but the TPC bioaccessibility has increased. Sonication reduced the quality loss of conventional drying treatments improving the quality of the dried product.

Selectins are essential for leukocyte recruitment in inflammation. Because of a lectin domain present in the selectin structure, we investigated the anti‐inflammtory activity of six mannose–glucose binding lectins from brazilian beans: Dioclea guianensis‐DguiL; D. grandiflora‐DgL; Cratylia floribunda‐CfL; D. violacea‐D.vL; D. virgata‐DvirL and Canavalia brasiliensis‐ConBr. The lectins were injected intravenously (i.v.) into rats (0.1 and 1.0 mg/kg; 30 min before irritants) and its activities compared to E. coli endotoxin (LPS,30 μg/kg i.v.). Three lectins (DvL, CfL and DguiL), although less intense than LPS, inhibited the neutrophil migration induced by carrageenan (Cg, 300 μg) in a dose‐dependent manner (0.1 and 1.0 mg/kg). DvL activity was reversed by 0.1 M α‐D‐methyl‐mannoside (α‐CH3), but not by 0.1 M α‐D‐galactose. The fMLP (44 ng)‐induced neutrophil migration was also reduced by these lectins. Endotoxin contamination of lectin samples could be excluded since α‐CH3 treatment reversed the DvL effect, but did not modify LPS inhibitory activity. Carrageenan (300 μg)‐induced paw oedema was also reduced by LPS or lectin treatments. Conversely, none of the tested lectins inhibited dextran (Dex, 300 μg)‐induced paw oedema, a classical leukocyte independent model, or zymosan (Zy, 1.0 mg)‐induced peritonitis and paw oedema. LPS showed no effect upon Dex‐induced paw oedema and barely reduced (25%) the oedematogenic effects of zymosan. As proposed for LPS, the lectin inhibitory activity was better observed on neutrophil‐mediated inflammatory reactions. We speculate that the plant lectin antiinflammatory activity is probably due to a competitive blockage of a common leukocyte and/or endothelial selectin carbohydrate ligand.

Croton nepetaefolius is a native plant from northeastern Brazil that belongs to the Euphorbiaceae family. The biological action of this plant has been extensively explored, being the secondary metabolites responsible for its properties alkaloids, diterpenes, and triterpenes. This study aimed to evaluate the ability of casbane diterpene (CD), isolated from the ethanolic extract of C. nepetaefolius, to inhibit microbial growth and biofilm formation of several clinical relevant species (bacteria and yeasts). It was found that CD possessed biocidal and biostatic activity against the majority of the species screened, with minimal active concentrations ranging between 125 and 500 µg/mL. In addition, it was observed that biofilm formation was inhibited even when the planktonic growth was not significantly affected. In conclusion, CD showed potential to be a natural tool for the treatment of diseases caused by different infectious microorganisms.