Hydrogels dressings based on guar gum and chitosan: Inherent action against resistant bacteria and fast wound closure.

Hydrogels made with depolymerized guar gum, oxidized with theoretical oxidation degrees of 20, 35 and 50 %, were obtained via Schiff's base reaction with N-succinyl chitosan. The materials obtained were subjected to characterization by FT-IR, rheology, swelling, degradation, and morphology. Additionally, their gelation time categorized all three hydrogels as injectable. The materials' swelling degrees in Phosphate-Buffered Saline (PBS) were in the range of 26-35 g of fluid/g gel and their pore size distribution was heterogeneous, with pores varying from 67 to 93 µm. All hydrogels degraded in PBS solution, but maintained around 40 % of their initial mass after 28 days, which was more than enough time for wound healing. The biomaterials were also flexible, self-repairing, adhesive and cytocompatible and presented intrinsic actions, regardless of the presence of additives or antibiotics, against gram-positive (Staphylococcus aureus, Staphylococcus epidermidis) and gram-negative bacteria (Escherichia coli). However, the most pronounced bactericidal effect was against resistant Staphylococcus aureus - MRSA. In vivo assays, performed with 50 % oxidized gum gel, demonstrated that this material exerted anti-inflammatory effects, accelerating the healing process and restoring tissues by approximately 99 % within 14 days. In conclusion, these hydrogels have unique characteristics, making them excellent candidates for wound-healing dressings.

Natural cordiaquinones as strategies to inhibit the growth and biofilm formation of methicillin-sensitive and methicillin-resistant Staphylococcus spp.

AIMS: The aim of this study was to investigate the antibacterial and antibiofilm potential of cordiaquinones B, E, L, N, and O against different Staphylococci strains, in addition to analyzing in silico the observed effect. METHODS AND RESULTS: The minimum inhibitory concentration (MIC) and the minimum bactericidal concentration (MBC) were determined according to CLSI guidelines. The inhibition of biofilm formation was investigated at sub-MICs. Atomic force microscopy (AFM) and density functional theory method were performed. The tested strains of Staphylococcus spp. were susceptible to cordiaquinones B, E, and L, among which cordiaquinone B exerted a bactericidal effect, confirmed by a bacterial growth curve study, against Staphylococcus saprophyticus. Cordiaquinones B and E showed lowest MBC values against S. saprophyticus. AFM revealed that cordiaquinone L reduced the mean cell size of S. saprophyticus. Cordiaquinones B and E inhibited the biofilm formation ability of S. aureus by ∼90%. The in silico analysis suggested that the antimicrobial activity of cordiaquinones is driven by their electron donation capability. CONCLUSIONS: Cordiaquinones inhibit the growth and biofilm formation (virulence factor) of both methicillin-sensitive and methicillin-resistant Staphylococci strains, indicating their antimicrobial potential.

Influence of Reduction with NaBH4 and HCl in Obtaining Amino Derivatives of Cashew Gum and Cytotoxic Profile.

Tree-exuded gums are natural polymers that represent an abundant raw material in the food and pharmaceutical industries. The cashew gum can be obtained by exudation of trees of the genus Anacardium, a native species of the Brazilian northeast; its polymer consists of monosaccharide units propitious to the action of chemical reactions that tend to improve their intrinsic characteristics among them, as the degree of hydro-solubility. The objective of this work was to modify the exudate gum of Anacardium occidentale (cashew gum (CG)) through an amine reaction. The modification was confirmed by Nuclear Magnetic Resonance (1H NMR), infrared spectroscopy (FTIR), gel permeation chromatography (GPC), zeta potential, and thermogravimetric analysis (TG). In addition, the chemical modification altered the molar mass and surface charge of the CG, and the amino group binding to the CG polymers was confirmed by FTIR spectra. In addition, cytotoxicity tests were performed where cell viability was estimated by an MTT assay on RAW 264.7 macrophages. Through these tests, it was found that the amine caused an increase in the thermal stability of the amino compounds and did not present cytotoxic potential at concentrations below 50.0 mg/L.

New Synthetic Sulfonamide Chalcone Induced Cell Cycle Arrest and Cell Death in Colorectal Adenocarcinoma Metastatic Cells (SW-620).

BACKGROUND: New chalcones have been developed from the insertion of organic groups, among them sulfonamides, presenting varied biological activity. OBJECTIVE: The aim of this work was to determine the antitumor potential of a new synthetic sulfonamide chalcone (SSC185) against a colorectal metastatic lymph node-derived colorectal cancer cell line (SW-620). METHODS: Synthesis and characterization, including crystallography, of SSC185 were performed. SSC185 showed a selective cytotoxic effect against colorectal cancer cell lines. Therefore, the cytotoxic effect of SSC185 against SW- 620 was further investigated. We used optical and fluorescence microscopy, flow cytometry and Western blot to determine the antitumor effects of SSC185. RESULTS: SSC185 induced cytotoxicity in SW-620 cells in a time and concentration-dependent manner. Cell cycle progression was disrupted, with increased G2/M cell number and consequent cell death, with morphological alterations associated with apoptosis and necrosis. Cell death was associated with the activation and cleavage of PARP, and with reduced expression of the pro-apoptotic Bax protein and caspase 8, depending on the SSC185 concentration tested. Expression of the necroptosis pathway proteins RIP and MLKL was also reduced. These proteins are phosphorylated during the process of necroptosis. CONCLUSION: We suggest that the mechanism involved in the cytotoxic effect of SSC185 against SW-620 in vitro may be related to the induction of cell cycle arrest in the G2/M phase and cell death by apoptosis or necroptosis, depending on the concentration used.

Antileishmanial activity of cordiaquinone E towards Leishmania (Leishmania) amazonensis.

Leishmaniasis is caused by several protozoan species of Leishmania, and being endemically present in 98 countries around the world, it is also a severe public-health problem. The available antileishmanial drugs are toxic and yet present risks of recurrent infection. Efforts to find new, effective, and safe oral agents for the treatment of leishmaniasis are continuing throughout the world. This work aimed to evaluate the antileishmania activity of cordiaquinone E (CORe), isolated from the roots of Cordia polycephala (Lam.) I. M. Johnston. Cytotoxicity, and possible mechanisms of action against promastigote and amastigote forms of Leishmania amazonensis were examined. CORe was effective in inhibiting promastigote (IC50 4.5 ± 0.3 µM) and axenic amastigote (IC50 2.89 ± 0.11 µM) growth in concentrations found non-toxic for the host cell (CC50 246.81 ± 14.5 µM). Our results revealed that CORe presents direct activity against the parasite, inducing cell death by apoptosis. CORe present greater activity against intracellular amastigotes (EC50 1.92 ± 0.2 µM), yet with much higher selectivity indexes than the reference drugs, being respectively more benign towards RAW 264.7 macrophages than meglumine antimoniate and amphotericin B, (respectively by 4.68 and 42.84 fold). The antiamastigote activity was associated with increased TNF-α, IL-12, NO, and ROS levels, as well as decreased IL-10 levels. These results encourage the progression of studies on this compound for the development of new leishmanicidal agents.

Methyl gallate: Selective antileishmanial activity correlates with host-cell directed effects.

Leishmaniasis is a widespread tropical infection caused by different species of Leishmania protozoa. Many of the available drugs against the disease are toxic and in certain cases parasite drug resistance is developed. The discovery of drugs for the treatment of leishmaniasis is a pressing concern. In the present work, we describe in vitro studies of the phenolic compound methyl gallate (MG) against Leishmania (Leishmania) amazonensis and its possible mechanisms of action. The in vitro activity of MG was assayed against L. amazonensis (promastigotes, axenic amastigotes, and intramacrophagic amastigotes). Cytotoxicity tests were performed with J774A.1 macrophages and THP-1 cell derived macrophages. To evaluate mechanisms of action, we analyzed cellular TNF-α, IL-12, IFN-γ, IL-10, IL-6, NO, ROS levels, arginase activity, and structural mechanisms (phagocytic and lysosomal activities) involving macrophage activation. Meglumine antimoniate and amphotericin B were used as reference drugs. It was observed that MG effectively inhibited the growth of both promastigote (IC50 5.71 µM) and amastigote-like forms (EC50 5.39 µM), with much higher selectivity indexes than the reference drugs, being more benign towards J774A.1 macrophages than meglumine antimoniate and amphotericin B, at 1631- and 70.92-fold respectively, with respect to the promastigote form. Additionally, MG proved to be even more active against intracellular amastigotes of the parasite (EC50 4.24 µM). Our results showed that antileishmania activity was associated with increased TNF-α, IL-12, NO and ROS levels, as well as decreased IL-6 and decreased arginase activity. In addition, MG induced increased phagocytic capability, and lysosomal volume in macrophages; structural parameters of microbicidal activity. Taken together, our results suggest that MG may be a promising candidate for new drug development against leishmaniasis.

4-Hydroxy-pyran-2-one and 3-hydroxy-N-methyl-2-oxindole derivatives of Salinispora arenicola from Brazilian marine sediments.

Three new 3-hydroxy-N-methyl-2-oxindole (1 and 2) and 4-hydroxy-pyran-2-one (3) derivatives, along with the known 3-hydroxy-N-methyl-2-oxindole (4) and 6-methoxy-N-methylisatin (5) were isolated from a marine Salinispora arenicola strain from sediments of the St. Peter and St. Paul Archipelago, Brazil. The structures of the new compounds were elucidated by a combination of spectroscopic (1D and 2D NMR and HR-ESIMS) data, including single-crystal X-ray diffraction analysis for 2 and 3. Compounds 1 to 5 were assayed for their antimicrobial properties, but only 4 and 5 were active against Enterococcus faecalis with MIC value of 15.6 µg/mL.

Antibacterial Salinaphthoquinones from a Strain of the Bacterium Salinispora arenicola Recovered from the Marine Sediments of St. Peter and St. Paul Archipelago, Brazil.

Salinaphthoquinones A-E (1-5) were isolated from a marine Salininispora arenicola strain, recovered from sediments of the St. Peter and St. Paul Archipelago, Brazil. The structures of the compounds were elucidated using a combination of spectroscopic (NMR, IR, HRESIMS) data, including single-crystal X-ray diffraction analysis. A plausible biosynthetic pathway for 1-5 is proposed. Compounds 1 to 4 displayed moderate activity against Staphylococcus aureus and Enterococcus faecalis with MIC values of 125 to 16 µg/mL.

Alendronate-induced gastric damage in normoglycemic and hyperglycemic rats is reversed by metformin.

Alendronate is a bisphosphonate widely used for the treatment of osteoporosis; however, one of its main adverse reactions is gastric ulcer. Metformin is an oral antihyperglycemic agent that has several beneficial effects, including healing, gastroprotective and anti-tumoral action. This study aimed to evaluate the gastroprotective activity of metformin in alendronate-induced gastric damage in normoglycemic and hyperglycemic rats. The treatment with 100 mg/kg of metformin showed a significant gastroprotective effect in damage induced by alendronate (50 mg/kg) in macroscopic analysis and the analysis of light microscopy and atomic force microscopy. The results suggested metformin decreased the inflammatory response by reducing the expression of proinflammatory cytokines (TNF-α, IL-1ß and IL-6), myeloperoxidase activity, and malondialdehyde levels. Also, the results suggested that metformin induces the maintenance of basal levels of collagen and increase the production of mucus. Interestingly, with the presence of the AMPK inhibitor (Compound C), metformin presented impairment of its gastroprotective action. The gastroprotective effect of metformin might be related to the activation of the AMPK pathway. These findings revealed that metformin has a gastroprotective action and may be considered a therapeutic potential for the prevention and treatment of gastric lesions induced by alendronate.

α, ß-Amyrin, a pentacyclic triterpenoid from Protium heptaphyllum suppresses adipocyte differentiation accompanied by down regulation of PPARγ and C/EBPα in 3T3-L1 cells.

Previous studies have reported the anti-obesity effects of α, ß-Amyrin in high fat-fed mice. This study aimed to evaluate whether α, ß-Amyrin has an anti-adipogenic effect in 3T3-L1 murine adipocytes and to explore the possible underlying mechanisms. 3T3-L1 pre-adipocytes were differentiated in a medium containing insulin, dexamethasone, and 1-methyl-3-isobutylxanthine. Cytotoxicity of α, ß-Amyrin was assessed by MTT assay. Lipid content in adipocytes was determined by Oil-Red O staining. In addition, the protein expression levels of peroxisome proliferator-activated receptor gamma (PPARγ), CCAAT/enhancer binding proteins alpha (C/EBPα), beta (C/EBPß), and delta (C/EBPδ) and glucose transporter 4 (GLUT4) were determined by qRT-PCR and western blot analysis. Oil-Red O staining revealed markedly reduced fat accumulation by α, ß-Amyrin (6.25-50 µg/mL) without affecting cell viability. Furthermore, our results indicate that α, ß-Amyrin can significantly suppress the adipocyte differentiation by downregulating the expression levels of adipogenesis-related key transcription factors such as PPARγ and C/EBPα, but not C/EBPß or C/EPBδ. In addition, the protein expression of membrane GLUT4 in 3T3- L1 adipocytes treated with α, ß-Amyrin was significantly higher than in control cells, indicating that α, ß-Amyrin augments glucose uptake. These findings suggest that α, ß-Amyrin exerts an anti-adipogenic effect principally via modulation of lipid and carbohydrate metabolism in 3T3-L1cells. The present in vitro findings, taken together with our earlier observation of the anti-obesity effect in vivo, suggest that α, ß-Amyrin can be developed as a new therapeutic agent for treatment and prevention of obesity.

Spirostanol glucosides from the leaves of Cestrum laevigatum L.

Two new steroidal saponins, (25R)-spirost-5-ene-3ß,26ß-diol 3-O-α-L-rhamnopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 4)-[(1 → 2)-α-L-rhamnopyranosyl]-ß-D-glucopyranoside (1) and (25R)-spirost-6-ene-3ß,5ß-diol 3-O-α-L-rhamnopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 4)-[(1 → 2)-α-L-rhamnopyranosyl]-ß-D-glucopyranoside (2), along with the known diosgenin 3-O-α-L-rhamnopyranosyl-(1 → 4)-α-L-rhamnopyranosyl-(1 → 4)-ß-D-glucopyranoside (3), chonglouoside SL-5 (4) and Paris saponin Pb (5) were isolated from the leaves of Cestrum laevigatum. The structures of the compounds were determined using spectroscopic analyses including HRESI-MS, 1D and 2D NMR data, followed by comparison with data from the literature. Among them, two are particularly unique, compound 1 is the first (6)Δ-spirostanol saponin and compound 2 has an unusual C-26 hydroxyl in the (5)Δ-spirostanol skeleton. Antifungal testing showed a potent activity to formosanin C against Candida albicans and Candida parapsilosis. Evaluation of the cytotoxic activity indicated that compound 1 has a moderate activity against HL-60 and SF-295 cell lines, while compound 2 were active only against HL-60.

The Resin from Protium heptaphyllum Prevents High-Fat Diet-Induced Obesity in Mice: Scientific Evidence and Potential Mechanisms.

Herbal compounds rich in triterpenes are well known to regulate glucose and lipid metabolism and to have beneficial effects on metabolic disorders. The present study investigated the antiobesity properties of resin from Protium heptaphyllum (RPH) and the possible mechanisms in mice fed a high-fat diet (HFD) for 15 weeks. Mice treated with RPH showed decreases in body weight, net energy intake, abdominal fat accumulation, plasma glucose, amylase, lipase, triglycerides, and total cholesterol relative to their respective controls, which were RPH unfed. Additionally, RPH treatment, while significantly elevating the plasma level of ghrelin hormone, decreased the levels of insulin, leptin, and resistin. Besides, HFD-induced increases in plasma levels of proinflammatory mediators TNF-α, IL-6, and MCP-1 were significantly lowered by RPH. Furthermore, in vitro studies revealed that RPH could significantly inhibit the lipid accumulation in 3T3-L1 adipocytes (measured by Oil-Red O staining) at concentrations up to 50 µg/mL. These findings suggest that the antiobese potential of RPH is largely due to its modulatory effects on various hormonal and enzymatic secretions related to fat and carbohydrate metabolism and to the regulation of obesity-associated inflammation.

The in-vitro and in-vivo inhibitory activity of biflorin in melanoma.

Biflorin, an ortho-naphthoquinone, is an active compound found in the roots of Capraria biflora L. It has been reported that biflorin presents anticancer activity, inhibiting both tumor cell line growth in culture and tumor development in mice. The aim of this study was to examine the effectiveness of biflorin treatment using both in-vitro and in-vivo melanoma models. Biflorin displayed considerable cytotoxicity against all tested cell lines, with half maximal inhibitory concentration values ranging from 0.58 µg/ml in NCI H23 (human lung adenocarcinoma) to 14.61 µg/ml in MDA-MB-231 (human breast cancer) cell lines. In a second set of experiments using B16 melanoma cells as a model, biflorin reduced cell viability but did not cause significant increase in the number of nonviable cells. In addition, the DNA synthesis was significantly inhibited. Flow cytometry analysis showed that biflorin may lead to an apoptotic death in melanoma cells, inducing DNA fragmentation and mitochondria depolarization, without affecting membrane integrity. In B16 melanoma-bearing mice, administration of biflorin (25mg/day) for 10 days inhibited tumor growth, and also increased the mean survival rate from 33.3±0.9 days (control) to 44.5±3.4 days (treated). Our findings suggest that biflorin may be considered as a promising lead compound for designing new drugs to be used in the treatment of melanoma.

Synthesis and anticancer activities of some novel 2-(benzo[d]thiazol-2-yl)-8-substituted-2H-pyrazolo[4,3-c]quinolin-3(5H)-ones.

A series of 2-(benzo[d]thiazol-2-yl)-8-substituted-2H-pyrazolo[4,3-c]quinolin-3(5H)-ones (3a-g) have been synthesized and evaluated for their in vitro antiproliferative activities against four human cancer cell lines: MDA-MB-435 (breast), HL-60 (leukemia), HCT-8 (colon) and SF-295 (central nervous system). The results showed that the compounds 3b (2-(benzo[d]thiazol-2-yl)-8-methyl-2H-pyrazolo[4,3-c]quinolin-3(5H)-one) and 3c (2-(benzo[d]thiazol-2-yl)-8-bromo-2H-pyrazolo[4,3-c]quinolin-3(5H)-one) exhibited good cytotoxicity for three cell lines with IC(50) values lower than 5 µg/mL. Analysis of theoretical toxicity risks have shown medium tumorigenic and irritant risks related to 3b and 3c in contrast to doxorubicin, the positive control.

Cytotoxic activity of naphthoquinones with special emphasis on juglone and its 5-O-methyl derivative.

The cytotoxicity of nine naphthoquinones (NQ) was assayed against HL-60 (leukaemia), MDA-MB-435 (melanoma), SF-295 (brain) and HCT-8 (colon), all human cancer cell lines, and peripheral blood mononuclear cells (PBMC), as representatives of normal cells, after 72h of incubation. 5-Methoxy-1,4-naphthoquinone was the most active compound, showing IC(50) values in the range of 0.31 (1.7microM) in HL-60 to 0.88microg/mL (4.7microM) in SF-295 and IC(50) of 0.69microg/mL (3.7microM) against PBMC. With the introduction of a bromo-substituent in position 2 or 3 of juglone, the IC(50) significantly decreased, regardless of the position on the NQ moiety. However, compared with juglone methyl ether, the halogen substitution decreased the activity. To further understand the mechanism underlying the cytotoxicity of 5-methoxy-1,4-naphthoquinone, studies involving DNA fragmentation, cell cycle analysis, phosphatidyl serine externalization, mitochondrial depolarization and activation of caspases 8 and 3/7 were performed in HL-60 cell line, using doxorubicin as a positive control. The results indicate that the cytotoxic 5-methoxy-1,4-naphthoquinone activates caspases 8 and 3/7 and thus induces apoptosis independent of mitochondria.