Structural study and antimicrobial and wound healing effects of lectin from Solieria filiformis (Kützing) P.W.Gabrielson.

The SfL-1 isoform from the marine red algae Solieria filiformis was produced in recombinant form (rSfL-1) and showed hemagglutinating activity and inhibition similar to native SfL. The analysis of circular dichroism revealed the predominance of ß-strands structures with spectra of ßI-proteins for both lectins, which had Melting Temperature (Tm) between 41 °C and 53 °C. The three-dimensional structure of the rSfL-1 was determined by X-ray crystallography, revealing that it is composed of two ß-barrel domains formed by five antiparallel ß chains linked by a short peptide between the ß-barrels. SfL and rSfL-1 were able to agglutinate strains of Escherichia coli and Staphylococcus aureus and did not show antibacterial activity. However, SfL induced a reduction in E. coli biomass at concentrations from 250 to 125 µg mL-1, whereas rSfL-1 induced reduction in all concentrations tested. Additionally, rSfL-1 at concentrations from 250 to 62.5 µg mL-1, showed a statistically significant reduction in the number of colony-forming units, which was not noticed for SfL. Wound healing assay showed that the treatments with SfL and rSfL-1 act in reducing the inflammatory response and in the activation and proliferation of fibroblasts by a larger and fast deposition of collagen.

Cashew nut shell liquids: Antimicrobial compounds in prevention and control of the oral biofilms.

OBJECTIVE: The aim was to evaluate the antibacterial and antibiofilm activity of natural (n-CNSL) and technical (t-CNSL) cashew nut shell liquid against streptococci and enterococci related to dental caries and chronic apical periodontitis, respectively. MATERIAL AND METHODS: Minimum inhibitory concentrations (MIC) and minimal bactericidal concentration (MBC) were determined to assess the antimicrobial effect of both CNSLs (n-CSNL and t-CNSL) against S. oralis ATCC 10557, S. sobrinus ATCC 6715, S. parasanguinis ATCC 903, S. mutans UA 159 and E. faecalis ATCC 19433. The antibiofilm activity was evaluated by total biomass quantification, colony forming unit (CFU) counting and scanning electron microscopy (SEM). Furthermore, cytotoxic effect of the substances was evaluated on L929 and HaCat cell lines by MTS assay. RESULTS: The n-CNSL and t-CNSL showed inhibitory and bactericidal effect against all strains tested in this study, with MIC and MBC values ranging from 1.5 to 25 µg/mL. Overall, both CNSLs showed significant reduction in biomass quantification and enumeration of biofilm-entrapped cells for the strains analyzed, in biofilm formation and preformed biofilms (p < 0.05). In biofilm inhibition assay, the t-CNSL and n-CNSL showed reduction in biomass and CFU number for all bacteria, except in cell viability of S. parasanguinis treated with t-CNSL (p > 0.05). Indeed, SEM images showed a reduction in the amount of biomass, bacterial cells and changes in cellular morphology of S. mutans. CONCLUSION: In conclusion, both substances showed effective antibacterial and antibiofilm activity against the strains used in the study, except in viability of S. parasanguinis cells treated with t-CNSL.

Wound healing activity of lectin isolated from seeds of Centrolobium microchaete Mart. ex Benth. on cutaneous wounds in mice.

This study aims to evaluate the wound healing potential of lectin isolated from the seeds of Centrolobium microchaete (Mart. ex Benth) (CML) on cutaneous wounds in mice. CML did not show cytotoxicity on murine dermal fibroblasts (L929 cell line). The wounds treated with CML (200 µg/mL) showed a decrease in area within 12 days post-operative (P.O.) when compared to control. On 3rd and 7th day P.O., the CML-treated group exhibited fibroblast proliferation and neovascularization. On 12th day P.O., complete restructuring of the epithelial layer and connective tissue was observed in the CML-treated group, whereas control groups exhibited incomplete reepithelialization. CML treatment enhanced the wound closure via the wound contraction process, resulting in the restructuring of the skin layers on 12th day P.O. In conclusion, CML induced a fast and efficient wound healing, suggesting that it can be used as a promising therapeutic tool to heal acute wounds.

Antimicrobial activity and antibiotic synergy of a biphosphinic ruthenium complex against clinically relevant bacteria.

The aim of this study was to investigate the antibacterial activity, antibiotic-associated synergy, and anti-biofilm activity of the ruthenium complex, cis-[RuCl2 (dppb) (bqdi)]2+ (RuNN). RuNN exhibited antimicrobial activity against Gram-positive bacteria with minimum inhibitory concentration (MIC) values ranging from 15.6 to 62.5 µg ml-1 and minimum bactericidal concentration (MBC) values ranging from 62.5 to 125 µg ml-1. A synergistic effect against Staphylococcus spp. was observed when RuNN was combined with ampicillin, and the range of associated fractional inhibitory concentration index (FICI) values was 0.187 to 0.312. A time-kill curve indicated the bactericidal activity of RuNN in the first 1-5 h. In general, RuNN inhibited biofilm formation and disrupted mature biofilms. Furthermore, RuNN altered the cellular morphology of S. aureus biofilms. Further, RuNN did not cause hemolysis of erythrocytes. The results of this study provide evidence that RuNN is a novel therapeutic candidate to treat bacterial infections caused by Staphylococcus biofilms.

Antihyperglycemic and antioxidant activities of a lectin from the marine red algae, Bryothamnion seaforthii, in rats with streptozotocin-induced diabetes.

The aim of the study was to assess the antihyperglycemic, antilipidemic, and antioxidant effects of a lectin isolated from Bryothamnion seaforthii (BSL), on rats with streptozotocin (STZ)-induced diabetes. The disease model was induced by low-dose injections of STZ. Diabetic rats were treated with NaCl 150 mM, metformin, and BSL at different concentrations. Blood collection was carried out at 0, 30, 60, 90, and 120 days after hyperglycemia confirmation via the assessment of seric glucose, total cholesterol, and triglycerides, assessment of the enzymatic levels of glutathione peroxidase (GPx), catalase (CAT), and superoxide dismutase (SOD), and the determination of insulin resistance by a homeostasis model of assessment-insulin resistance (HOMA-IR) as well as a homeostasis model of assessment of ß-cells resistance (HOMA-ß). The BSL-treated animals at all three concentrations showed a significant reduction in levels of glucose, cholesterol, total cholesterol, and triglycerides. Moreover, BSL increased the enzymatic activity of GPx and SOD. Index assessments of HOMA-IR and HOMA-ß confirmed that BSL treatment significantly decreased insulin resistance and ß-cell hypersecretion, respectively. In conclusion, BSL treatment might exert hypoglycemic and hypolipidemic effects, diminish insulin resistance, and ameliorate pancreatic ß-cell function along with enzymatic activities toward oxidative stress caused by diabetes mellitus type 2 (T2DM).

Molecular Mechanisms Involved in the Antitumor Activity of Isolated Lectins from Marine Organisms: A Systematic Review.

INTRODUCTION: Tumor cells may present several molecular alterations that favor their malignancy, among which there is the expression of tumor-related antigens, such as truncated T-glycans, Thomsen-nouvelle, sialyl-Lewis X and sialyl Tn, which may help in the diagnosis and treatment using specific target molecules. Lectins are ubiquitous proteins capable of interacting with specific carbohydrates. Lectins isolated from marine organisms have important characteristics such as low immunogenicity and can bind to complex glycans compared to plant lectins. OBJECTIVE: This work evaluated, through a systematic review, the molecular mechanisms of antitumor activity of lectins isolated from marine organisms. METHODOLOGY: The Pubmed, Lilacs, Science Direct, Wiley and Scopus databases were reviewed using the descriptors: marine lectin and cancer. Articles in English, published between January 2008 and December 2018, which proposed the molecular mechanisms of anticancer activity of lectins from marine organisms were eligible for the study. RESULTS: 17 articles were eligible. The lectins showed promising performance against cancer cells, presenting specific cytotoxicity for some types of malignant cells. The articles presented several lectins specific to different carbohydrates, modulating: pro and anti-apoptotic proteins, transcription factor E2F-1, via mitogen-activated protein kinase. In addition, exogenous lectin expression in cancer cells has been shown to be a promising way to treat cancer. CONCLUSION: This review showed the various studies that described the molecular mechanisms caused by marine lectins with antineoplastic potential. This knowledge is relevant for the development and use of the next generations of lectins isolated from marine organisms, supporting their potential in cancer treatment.

Chemical composition, antioxidant, antimicrobial and antibiofilm activities of Vitex gardneriana schauer leaves's essential oil.

This study aimed to determinate the chemical composition and evaluate the antimicrobial and antioxidant activity of the essential oil obtained from leaves of V. gardneriana. The Vitex gardneriana leaves's were hydrodistilled to obtain the essential oil and the chemical composition determined by GC/MS analysis. The antimicrobial activities were determined by microdilution method. The activity of essential oil on biofilm was evaluated by quantification of total biomass and enumeration of biofilm-entrapped viable cells. The antioxidant activity was assessed by DPPH free radical assay, ferrous ion chelating assay, ferric-reducing antioxidant power and ß-carotene bleaching assay. Furthermore, the essential oil was tested on viability of health human, animal cells and the microcrustacean Artemia sp. The essential oil showed high content of sesquiterpenes and very low content of monoterpenes. Regarding activity on planktonic cells, the essential oil reduced the growth of the all species tested but showed MIC values only to S. aureus (0.31%). In general, the essential oil reduced significantly the biofilm biomass and the number of viable cells of bacteria and yeasts, mainly on biofilm formation. The essential oil showed a potential antioxidant activity, mainly on ß-carotene oxidation. Moreover, the essential oil reduced the cell viability of murine fibroblasts but not show viability reduction of human keratinocytes. Furthermore, the oil not show toxicity against the microcrustacean. Thus, the essential oil from V. gardneriana leaves may be considered as an important alternative against biofilms formed by bacteria and yeasts related to infections, as well as a natural antioxidant and non-toxic substance on human cells.

Antibacterial activity of a new lectin isolated from the marine sponge Chondrilla caribensis.

A new lectin from the marine sponge Chondrilla caribensis (CCL) was isolated by affinity chromatography in Sepharose 6B media. CCL is a homotetrameric protein formed by subunits of 15,445 ±2Da. The lectin showed affinity for disaccharides containing galactose and mucin. Mass spectrometric analysis revealed about 50% of amino acid sequence of CCL, which showed similarity with a lectin isolated from Aplysina lactuca. Secondary structure consisted of 10% α-helix, 74% ß-sheet/ß-turn and 16% coil, and this profile was unaltered in a broad range of pH and temperatures. CCL agglutinated Staphylococcus aureus, S epidermidis and Escherichia coli, and it was able to reduce biofilm biomass, but showed no inhibition of planktonic growth of these bacteria. CCL activity was inhibited by α-lactose, indicating that Carbohydrate Recognition Domain (CRD) of the lectin was involved in antibiofilm activity.

Structural characterization of two isolectins from the marine red alga Solieria filiformis (Kützing) P.W. Gabrielson and their anticancer effect on MCF-7 breast cancer cells.

As described in the literature, Solieria filiformis lectin (SfL) from the marine red alga S. filiformis was found to have antinociceptive and anti-inflammatory effects. In this study, we characterized two SfL variants, SfL-1 and SfL-2, with molecular mass of 27,552Da and 27,985Da, respectively. The primary structures of SfL-1 and SfL-2 consist of four tandem-repeat protein domains with 67 amino acids each. SfL-1 and -2 showed high similarity to OAAH-family lectins. 3D structure prediction revealed that SfL-1 and -2 are composed of two ß-barrel-like domains formed by five antiparallel ß-strands, which are connected by a short peptide linker. Furthermore, the mixture of isoforms (SfLs) showed anticancer effect against MCF-7 cells. Specifically, SfLs inhibited 50% of viability in MCF-7 cells after treatment at 125µg.mL-1, while the inhibition of Human Dermal Fibroblasts (HDF) was 34% with the same treatment. Finally, 24h after treatment, 25% of MCF-7 cells were in early apoptosis and 35% in late apoptosis. Evaluation of pro- and anti-apoptotic gene expression of MCF-7 cells revealed that SfLs induced caspase-dependent apoptosis within 24h.

Effect of the triterpene 3ß, 6ß, 16ß-trihydroxylup-20(29)-ene isolated from the leaves of Combretum leprosum Mart. on cutaneous wounds in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Combretum leprosum Mart. is a native species of the Caatinga, an important biome in the Brazilian semi-arid region. This species is commonly used in Brazil as a healing agent, as well as for the treatment of skin diseases. AIM OF THE STUDY: This study investigated the healing potential of the ethanolic extract (EECL) and the bioactive triterpene 3ß, 6ß, 16ß-trihydroxylup-20 (29)-ene (CLF-1) isolated from the leaves of C. leprosum. MATERIALS AND METHODS: Skin wounds (1cm(2)) were created in the dorsal zone of mice with a scalpel blade number 15. The treatment consisted in a daily topical application of 100 µl of 150 mM NaCl, EECL and CLF-1 (at 10 µg/100 µl) for 12 days. The lesions were then macro and microscopically evaluated. RESULTS: On postoperative day (POD) 2, the lesions treated with EECL and CLF-1 showed a moderate presence of vessels of the granulation tissue progressing in the dermis. The same effect was not observed in the control group. The treatment with EECL and CLF-1 stimulated angiogenesis, resulting in a rapid deposition of extracellular matrix (ECM). Moreover, the animals treated with EECL and CLF-1 showed smaller lesions on POD 7, primarily due to the contraction in the reticular dermis induced by organization of myofibroblasts, which was not observed in the group treated with NaCl. In addition, the lesions treated with EECL and CLF-1 showed ECM restructuration and presence of epithelium coating, which was not observed in the group treated with NaCl, in which the lesions showed no epithelial lining, suggesting delayed healing. CONCLUSION: CLF-1 isolated from the leaves of C. leprosum may be considered to be an important molecule for the treatment of skin lesions. However, further investigations are necessary to establish its role in chronic lesions and to elucidate the mechanism of action involved in the cutaneous healing process. To the best of our knowledge, this is the first report describing the pro-healing activity of the ethanolic extract and the triterpene 3ß, 6ß, 16ß-trihydroxylup-20(29)-ene isolated from leaves of C. leprosum.

Antimicrobial effect of the triterpene 3ß,6ß,16ß-trihydroxylup-20(29)-ene on planktonic cells and biofilms from Gram positive and Gram negative bacteria.

This study evaluated the antimicrobial effect of 3ß,6ß,16ß-trihydroxylup-20(29)-ene (CLF1), a triterpene isolated from Combretum leprosum Mart., in inhibiting the planktonic growth and biofilms of Gram positive bacteria Streptococcus mutans and S. mitis. The antimicrobial activity was assessed by determining the minimum inhibitory concentration (MIC) and minimum bactericidal concentration (MBC). The antibiofilm potential was determined by quantifying total biomass and enumerating biofilm-entrapped viable bacteria. In addition, the acute toxicity of CLF1 on Artemia sp. nauplii was also determined. The results showed that CLF1 was able in inhibiting the growth of S. mutans and S. mitis with MIC and MBC of 7.8 µg/mL and 15.6 µg/mL, respectively. CLF1 was highly effective on biofilms of both bacteria. Only 7.8 µg/mL CLF1 was enough to inhibit by 97% and 90% biomass production of S. mutans and S. mitis, respectively. On the other hand, such effects were not evident on Gram negative Pseudomonas aeruginosa and Klebsiella oxytoca. The toxicity tests showed that the LC50 of CLF1 was 98.19 µg/mL. Therefore, CLF1 isolated from C. leprosum may constitute an important natural agent for the development of new therapies for caries and other infectious diseases caused by S. mutans and S. mitis.

Antimicrobial peptide control of pathogenic microorganisms of the oral cavity: a review of the literature.

Antimicrobial peptides, molecules produced in many different organisms, have high biocidal activity against several microorganisms. However, several questions about these molecules remain unclear. Therefore, this report details a systematic survey of the literature on the use of antimicrobial peptides against oral pathogens and indicates which peptides and microorganisms are most extensively studied. Articles were located using the PubMed and Science Direct databases with the following inclusion criteria: publication date between 2002 and 2011; keywords "biofilm OR biological film OR biological layer OR bacterial growth" AND "peptide" AND "oral cavity OR mouth OR buccal mucosa OR oral mucosa OR mouth mucosa"; and abstract in English. A total of 73 articles were selected after refinement of the data. An increase in publications focusing on the use of antimicrobial peptides against oral microorganisms was observed. In addition, the peptides produced by cells of the oral mucosa (defensins, LL-37 and histatins) as well as Streptococcus mutans (among cariogenic bacteria) and Porphyromonas gingivalis (among periodontal bacteria) were the most studied subjects. It was concluded that the use of antimicrobial peptides as a tool for microbial control is of increasing importance, likely due to its widespread use, mechanism of action, and low rates of bacterial resistance.

Lectin from Canavalia brasiliensis seeds (ConBr) is a valuable biotechnological tool to stimulate the growth of Rhizobium tropici in vitro.

To study the interactions between a Rhizobium tropici strain and lectins isolated from the seeds of Canavalia ensiformis (ConA) and Canavalia brasiliensis (ConBr), a lectin fluorescence assay was performed. In addition, an experiment was designed to evaluate the effect of the two lectins on bacterial growth. Both lectins were found to bind to R. tropici cells, but the interactions were inhibited by D-mannose. Interestingly, only ConBr stimulated bacterial growth in proportion to the concentrations used (15.6-500 µg/mL), and the bacterial growth stimulation was inhibited by D-mannose as well. Structure/Function analyses by bioinformatics were carried out to evaluate the volume and carbohydrate recognition domain (CRD) configuration of ConA and ConBr. The difference of spatial arrangement and volume of CRD may indicate the variation between biological activities of both lectins. The results suggest that ConBr could be a promising tool for studies focusing on the interactions between rhizobia and host plants.