Antibacterial properties and modulation analysis of antibiotic activity of NaCe(MoO4)2 microcrystals.

This study reports the antibacterial properties and modulation analysis of antibiotic activity by NaCe(MoO4)2 microcrystals as well as their structural and morphological characterization. Evaluation of the antibacterial and antibiotic-modulating activity was carried out using the broth microdilution method. The Minimum Inhibitory Concentrations (MICs) of the compounds were expressed as the geometric mean of the triplicate values obtained through the use of Resazurin. Compound concentrations in the plates ranged from 512 to 0.5 µg/mL. Regarding its direct antibacterial activity, NaCe(MoO4)2 had a MIC ≥ 1024 µg/mL against all studied strains. As for its modulatory effect, it presented synergism with the antibiotic Gentamicin against the S. aureus strain and with Norfloxacin against E. coli, causing a reduction of 75% and 60%, respectively, in the antibiotic quantity required to have the same effect on the strain in study.

Cholesterol and ergosterol affect the activity of Staphylococcus aureus antibiotic efflux pumps.

The aim of this study is to evaluate the effect of ergosterol on steroids and cholesterol efflux pumps in multidrug resistant strains of S. aureus. Were used RN4220 harboring plasmid pUL5054, which carries the gene encoding the MsrA macrolide efflux protein; and IS-58, which possesses the TetK tetracycline efflux protein; 1199B resists hydrophilic fluoroquinolones via a NorA-mediated mechanism and wild strain 1199B. The Minimal Inhibitory Concentration (MIC) was determined and the evaluation of possible inhibition of efflux pumps by reduction of MIC. Some of the detrimental effects on bacterial cells can be attributed to the detergent properties of cholesterol and ergosterol on account of their amphipathic structure. Besides the cholesterol did not affect directly the pump structure, a synergism was observed, maybe due the interaction with the cell membrane and interference in the lipid bilayer.

Inhibition of the NorA efflux pump of Staphylococcus aureus by synthetic riparins.

AIM: The goal of this study was to increase knowledge about the antimicrobial activity of some synthetic Riparin-derived compounds, alone or in combination with fluoroquinolone antibiotics, against a strain of Staphylococcus aureus resistant to fluoroquinolone by way of overexpression of the NorA efflux pump. METHODS AND RESULTS: Microdilution tests showed that Riparins A and B did not show any significant antibacterial activity against Staph. aureus strains. On the other hand, the intrinsic antibacterial activity increased with increasing lipophilicity of the compounds, in the following order: Riparin-D (MIC 256 µg ml-1 ; Log P 2·95) < Riparin-C (MIC 102 µg ml-1 ; Log P 3·22) < Riparin-E (MIC 16 µg ml-1 ; Log P 3·57). The addition of all riparins to growth media at subinhibitory concentrations caused an increase in the antibacterial activity of antibiotics against the NorA-overexpressing test strain. Riparin-B, which has two methoxyl groups at the phenethyl moiety, showed the best modulatory effect. CONCLUSIONS: Riparin-E is a good anti-staphylococci agent, while Riparin-B functions as a NorA efflux pump inhibitor. SIGNIFICANCE AND IMPACT OF THE STUDY: Our data suggest the possibility of using Riparin-B in combination with norfloxacin or ciprofloxacin for therapy of infections caused by multi-drug resistant Staph. aureus.

Antimicrobial effect of Lippia sidoides and thymol on Enterococcus faecalis biofilm of the bacterium isolated from root canals.

The species Lippia sidoides Cham. (Verbenaceae) is utilized in popular medicine as a local antiseptic on the skin and mucosal tissues. Enterococcus faecalis is the bacterium isolated from root canals of teeth with persistent periapical lesions and has the ability to form biofilm, where it is responsible for the failure of endodontic treatments. Essential oil of L. sidoides (EOLS) and its major component, thymol, were evaluated for reducing the CFU in biofilms of E. faecalis in vitro. The essential oil was obtained by hydrodistillation and examined with respect to the chemical composition, by gas chromatography-mass spectrometry (GC-MS). The GC-MS analysis has led to the identification of thymol (84.9%) and p-cymene (5.33%). EOLS and thymol reduced CFU in biofilms of E. faecalis in vitro (time of maturation, 72 h), with an exposure time of 30 and 60 min at concentrations of 2.5 and 10%. There was no statistical difference in effect between EOLS and thymol, demontrating that this phenolic monoterpene was the possible compound responsible for the antimicrobial activity of EOLS. This study provides a basis for the possible utilization of EOLS as an adjuvant in the treatment of root canals that show colonization by E. faecalis.

Antimicrobial activity and chemical composition of fixed oil extracted from the body fat of the snake Spilotes pullatus.

CONTEXT: Ethnozoological studies have shown that Spilotes pullatus Linn. (Colubridae: Ophidia), is associated with medicinal and magic-religious uses in Brazil. OBJECTIVES: This study was designed to determine the chemical composition of the oil extracted from the body fat of S. pullatus and to test its antimicrobial properties, alone and in association with aminoglycosides, against fungi and bacterial strains in concentrations ranging between 1024 and 0.5 µg/mL. MATERIAL AND METHODS: The snakes were collected in the Chapada do Araripe, county of Crato, Ceará State, Brazil. The oil was extracted in a Soxhlet apparatus using hexane. The methyl esters of the fatty acids present in the samples were identified using GC-MS. The antimicrobial and drug modulatory activities of oil were tested by microdilution against fungal and bacterial strains. RESULTS: The chemical composition of the fixed oils of S. pullatus identified 10 constituents representing 94.97% of the total sample. The percentages of saturated and unsaturated fatty acids were 33.59 and 61.38%, respectively, with the most abundant components being elaidic (37.26%). The oil did not demonstrate any antimicrobial or antifungal activity when tested alone, presenting MIC values ≥ 1024 µg/mL. However, when associated with antibiotics, it demonstrated synergistic effects with gentamicin against all the bacterial lineages assayed, and antagonistic effects with amikacin and neomycin against strains of Escherichia coli. CONCLUSIONS: Oil extracted from the body fat of S. pullatus did not demonstrate any inhibitory effects on bacterial or fungal activities, but was effective in modulating the effects of certain antibiotics.

Chromatographic analysis of selected phytosterols from Cyathea and their characterization by in silico docking to potential therapeutic targets.

Separation and quantification of lupeol, stigmasterol and swertiamarin in ethanolic extracts of selected Cyathea species have been developed using HPTLC and an attempt is made to explore the biopotential of phytochemicals against various proteins by computational analysis. Compounds were separated using the specific mobile phase and the developed plates were sprayed with respective spraying reagents. The 3D structure of the receptor proteins viz., 1VSN, 5BNQ, 6HN8, 7DN4 and 3TJU, and the 3D SDF structures of ligands like lupeol, stigmasterol and swertiamarin were retrieved from the Protein Data Bank (PDB) and NCBI-Pub Chem Compound database respectively. The Argus 4.0.1 is computer generated drug design screening software is employed to analyze the binding affinity of test compounds against the selected proteins in the form of E-values versus potential drug targets. The docking result was saved and visualized using Discovery Studio Visualizer. The terpenoid band with Rf value 0.79 depicted the presence of lupeol in C. gigantea (0.04%) and C. crinita (0.02%). The steroid band with Rf value 0.41 confirmed the presence of stigmasterol with varied frequency viz., C. nilgirensis (0.33%), C. gigantea (0.29%) and C. crinita (0.52%). Lupeol, stigmasterol and swertiamarin showed the interaction against the studied proteins viz., 1VSN, 5BNQ, 6HN8, 7DN4, 3TJU with varied energy values and interacting residues. The results of the virtual screening and molecular docking analysis suggest that the phytochemical compounds of Cyathea species viz., lupeol and stigmasterol were identified as possible lead molecules to fight against cancer and cytotoxicity.

Phenolic compounds and interaction between aminoglycosides and natural products of Lygodium venustum SW against multiresistant bacteria.

BACKGROUND: The aim of this work was to evaluate the interactions between aminoglycosides and the ethyl-acetate fraction of the fern Lygodium venustum SW (EAFLV) METHODS: The ethyl-acetate fraction was obtained from the ethanol extract of L. venustum and was assayed via the checkerboard method associated with aminoglycosides against two bacterial strains multiresistant to antibiotics. RESULTS: The antibiotic activity of all drugs, when associated with the ethyl-acetate fraction, was enhanced in an additive manner, except for the association between EAFLV and amikacin, which showed a synergistic interaction against the Escherichia coli strain. CONCLUSIONS: The results indicated that L. venustum can be a source of secondary metabolites to be used in association with antibiotics like aminoglycosides in antibiotic chemotherapy against resistant bacteria.

Investigation of the cytocidal potential of Rhinella jimi skin methanol extracts.

CONTEXT: Amphibian skins have wide variety of biologically active compounds associated with the natural defenses of these animals. OBJECTIVES: To study the in vitro anticancer activity of methanol extracts of the skin of Rhinella jimi Stevaux (Anura: Bufonidae). MATERIAL AND METHODS: The extract was obtained by cold methanol extraction for 96 h using dried skins (295 mg). The methanol skin extract was dried under reduced pressure, giving a 5.5% yield. In order to test for growth-inhibitory activity, in vitro tests were performed with the following cancer cell lines using concentrations ranging between 0.25-250 µg/mL of the extract by 48 h: K562 (leukemia), MCF-7 (breast), NCI-ADR (breast with MDR phenotype), UACC-62 (melanoma), NCI460 (lung), PCO3 (prostate), HT-29 (colon), OVCAR (ovary), and 786-0 (kidney). RESULTS: The methanol extract of R. jimi produced a growth inhibition in a dose-dependent manner against the most of the assayed cell lines. In addition to the growth inhibition, the extract induced the cell death in the ovary and colon lines (EC50 0.125 and 0.2 µg/mL, respectively), demonstrating 100% of inhibition with 2.5 µg/mL. However, prostate and leukemia cell lines demonstrated less sensitivity, with EC50 of 24 and 235 µg/mL, respectively. This is the first report about the anticancer activity by natural products from the skin of R. jimi. CONCLUSIONS: The methanol extracts of R. jimi significantly affected the growth of several cell lines, demonstrating that these compounds are a potential source of substances that could be utilized in cancer treatments.

Phytochemical prospection and modulation of aminoglycoside antibiotic activity by Croton campestris A.

BACKGROUND: Escherichia coli is known to produce enterotoxins whose properties and role in diarrheal disease have been extensively investigated; besides, this bacterium is related to several extra-intestinal problems in the intensive care unit and in surgical wound infections. Some species of Staphylococcus are recognized as etiological agents of opportunistic infections in animals and humans. This study is the first test on the modulation of antibiotic activity by Croton campestris A. against multiresistant strains of E. coli and Staphylococcus aureus. METHODS: In this study, the hexane and methanol extract of C. campestris A. was tested for antibacterial activity alone and in combination with aminoglycosides against bacterial strains. The synergy of the methanol and hexane extract was verified by microdilution method. RESULTS: A synergistic effect of both extracts combined with the aminoglycosides was demonstrated. CONCLUSIONS: It is suggested that the extracts from C. campestris A. could be used as a source of natural product derived from this plant with resistance-modifying antibacterial activity, providing a new weapon against the problem of bacterial resistance to antibiotics.

Evaluation of phytochemical composition, toxicity in Drosophila melanogaster and effects on antibiotics modulation of Plathymenia reticulata Benth extract.

Bacterial resistance is interfering with the action of antibiotics for clinical use in treating pathologies. The search for new substances capable of combating this resistance is necessary. An alternative to the search for these substances is in the extract of medicinal plants. Plathymenia reticulata, plant of the Fabaceae family, is a common tree species from the Brazilian cerrado, and is commonly used in areas of environmental degradation. This species is rich in phenolic compounds, such as flavonoids and tannins, compounds that are associated with various biological effects. A hydroethanolic extract from the bark of Plathymenia reticulata (HEPrB) was produced and then tests were carried out to verify the direct antibacterial activity, the modulatory effect of antibiotics for clinical use and their toxicity in Drosophila melanogaster flies. Through the analysis with UPLC, a wide variety of flavonoids contained in the HEPrB was observed. Direct antibacterial activity was observed for the standard strain of Staphylococcus aureus, however, the extract showed antagonistic activity or no significance in relation to the antibiotics tested in this study. As for toxicity, the HEPrB did not show significant damage in the proposed model. The results emphasize care when associating the consumption of teas with treatments with antibiotics for clinical use.

Antinociceptive and anti-inflammatory activities of Hymenaea martiana Hayne (Fabaceae) in mice.

Hymenaea martiana is a species popularly known in Northeastern Brazil as "jatobá" and used in folk medicine to treat pain and inflammation. The aim of this work was to evaluate the antinociceptive and anti-inflammatory activity of H. martiana. In the present study, we carried out an investigation about the effects of the crude ethanolic extract (Hm-EtOH) and the ethyl acetate fraction (Hm-AcOEt) in models of nociception and inflammation in mice. Chemical (acetic acid-induced writhing and formalin) and thermal stimuli (hot plate) were used for the evaluation of antinociceptive activity, while for the anti-inflammatory profile paw edema induced by carrageenan was used, along with leukocyte migration to the peritoneal cavity. The presence of the flavonoid astilbin in the samples was characterized through HPLC-DAD-MS analysis. Hm-EtOH and Hm-AcOEt (100, 200 and 400 mg.kg-1, i.p.) significantly reduced the number of abdominal contortions and decreased the paw licking time in the formalin test. In the hot plate, the extract increased the latency time of animals. Hm-EtOH and Hm-AcOEt inhibited significantly the increase in the edema after the administration of carrageenan. Hm-EtOH and Hm-AcOEt inhibited leukocyte migration in the peritonitis test. HPLC-DAD-MS analysis of Hm-EtOH and Hm-AcOEt revealed the presence of the flavonoid astilbin in the samples. According to the results of this study, both Hm-EtOH and Hm-AcOEt have antinociceptive and anti-inflammatory activities, which could be related with the presence of flavonoid in the extracts. The results reinforce the popular use of this plant.

Gastroprotective and cicatrizing activity of the Ziziphus joazeiro Mart. leaf hydroalcoholic extract.

Ziziphus joazeiro Mart., popularly known as 'juazeiro', is a species used in popular medicine for the treatment of bronchitis, gastric ulcers, skin wounds, and in the manufacture of cosmetic and food products. The objective of this study is to evaluate the gastroprotective and cicatrizing activity of the Z. joazeiro Mart. leaf hydroalcoholic extract (EHFZJ). The acute pre-clinical toxicity was determined by the single administration of the EHFZJ (2000 mg/kg/p.o.) and by assessing clinical signs of toxicity, according to established criteria by Malone, or mortality. Gastroprotective activity was identified through classical models of acute gastric lesions induced by indomethacin, absolute and acidified ethanol (100, 200 and 400 mg/kg/per os) and the physical barrier mechanism (400 mg/kg/per os or intraperitoneally). The cicatrizing activity of the EHFZJ was investigated by measuring the speed of wound closure and the percentage of contraction. The acute pre-clinical toxicity of EHFZJ showed no signs of toxicity and mortality. The EHFZJ demonstrated a gastroprotective effect at the 400 mg/kg dose in the classical models of acute gastric injury induced by indomethacin, absolute and acidified ethanol. The EHFZJ administration (orally) demonstrated significant inhibition, suggesting a possible physical barrier mechanism exists. The EHFZJ showed no significant differences in terms of percentage of contraction or the speed of wound closure during the observation times (0, 3, 7, 11 and 14 days). The results obtained in this study provide evidence of a potential gastroprotective activity for the Ziziphus joazeiro Mart. Leaf hydroalcoholic extract.

Factors influencing the virulence of Candida spp.

BACKGROUND: Diseases produced for Candida species (spp) are called candidiasis and this includes settling, superficial infection, deep tissue invasion and haematogenic dissemination (eyes, the skin, the kidneys and the brain). The species that more usually cause candidiasis are C. albicans, C. tropicalis and C. glabrata. These species usually are found in the normal microbial populations of the mucosae and can be pathogenic due the vulnerability of the host. OBJECTIVE: The objective of this paper is to review the factors that influence infection by Candida spp in order to empower health-workers in the management of such infections. METHODS: Data were retrieved from the bibliographical data banks of SCIELO, HIGHWIRE, PUBMED, LILACS and SCIRUS. CONCLUSIONS: Knowledge about factors such as environment, exoenzymes, preferred infection sites and other factors that are essential for combating Candida infection and the risks associated with infection, will enhance efficient management.

The antioxidative effects of bioactive products from Sargassum polycystum C. Agardh and Sargassum duplicatum J. Agardh against inflammation and other pathological issues.

The present study was aimed to determine the phenol, total flavonoids and antioxidant potentials of Sargassum polycystum C. Agardh and Sargassum duplicatum J. Agardh from south east coast of Tamil Nadu and India using DPPH, phophomolybdenum and hydrogen peroxide scavenging activity. The total phenols, total flavonoids and antioxidant activities of S. polycystum and S. duplicatum were determined. Highest phenols (33.49 and 149.52 mg GAE/g) were observed in chloroform extracts of S. polycystum and methanolic extracts of S. duplicatum. The acetone extracts of S. polycystumand S. duplicatum demonstrated maximum amount of flavonoids compared to other studied extracts. Maximum amount of phosphomolybdenum reduction was observed in acetone extracts of S. polycystum and methanolic extracts of S. duplicatum. The DPPH radical scavenging activity of different extracts of S. polycystum and S. duplicatum were as follows acetone > chloroform > Petroleum ether > methanol and acetone > chloroform > methanol >Petroleum ether respectively. The H2O2 scavenging activity of S. polycystum extracts were as follows Petroleum ether extracts of S. polycystum (67.9%) > acetone (67.3%) > chloroform (58.6%) > methanol (51.78%). Acetone extracts of S. duplicatum showed maximum inhibition (90.39%) followed by petroleum ether, chloroform and methanolic extracts (75.11, 72.37 and 54.59%) respectively. The present study results confirmed the antioxidant properties of the two selected brown seaweeds viz., S. polycytum and S. duplicatum. The total phenols, flavonoids and alkaloids may be responsible for the antioxidant activities.

Larvicidal activity of some medicinal plant extracts against filariasis fever mosquito, Culex quinquefasciatus (Say.) (Diptera: Culicidae).

OBJECTIVES: The present study was aimed to find the larvicidal activity of petroleum ether, chloroform, acetone and methanolic extracts of Dichanthium foveolatum (Del.) Roberty, Leptochloa uniflora Hochst, Pancratium triflorum Roxb and Molineria trichocarpa (Wight) N.P.Balakr against Culex quinquefasciatus. METHODS: The larvicidal potential of selected plant extracts were determined against 4th instar larvae of C. quinquefasciatus with various concentrations viz., 50, 100, 150, 200 and 250 mg/ml. The mortality counts were made after 24 h of incubation and LC50 values were calculated. RESULTS: Chloroform extracts of studied plants were showed highest larvicidal activity with remarkable irritant against the larva of C. quinquefasciatus. Highest larvicidal activity was observed in the chloroform extract of D. foveolatum against the larva of C. quinquefasciatus with LC50 = 277.03 mg/ml. The larvicidal activity of the studied plants as follows chloroform extract of D. foveolatum (LC50 = 277.03 mg/ml) >L. uniflora (LC50 = 300.56 mg/ml) >M. trichocarpa (LC50 = 306.60 mg/ml) >P. triflorum (LC50 318.42 mg/ml). The larvicidal potential of P. triflorum was as follows Chloroform > acetone > methanol > petroleum ether. The larvicidal activities of L. uniflora and M. trichocarpa were as follows Chloroform > petroleum ether > acetone > methanol respectively. The larvicidal potentials of D. foveolatum was as follows Chloroform > methanol > acetone > petroleum ether. CONCLUSION: The chloroform extract of D. foveolatum find use as broad-spectrum larvicidal agent in the near future. It is hoped that more work would be undertaken to evaluate the utility of these plant extracts for field applications considering the promising leads given by the present study.

Pancratium triflorum Roxb. (Amaryllidaceae) and Molineria trichocarpa (Wight) N.P. Balakr (Hypoxidaceae): Cytotoxic and antioxidant activities.

The present investigation was carried out to evaluate the antioxidant and cytotoxic activities of Pancratium triflorum Roxb and Molineria trichocarpa were collected from South Vagaikulam, Tirunelveli district, Tamil Nadu, India. The antioxidant activities of P. triflorum extracts were as follows with the IC50 values methanol (228.13 µg/mL) > chloroform (311.33 µg/mL) > acetone (398.08 µg/mL) > petroleum ether (410.16 µg/mL). The antioxidant activities of P. triflorum and M. trichocarpa extracts were as follows with the IC50 values methanol (80.93 µg/mL) > acetone (98.02 µg/mL) > chloroform (186.84 µg/mL) > petroleum ether (209.64 µg/mL). Among the various extracts of P. triflorum, methanolic extracts showed the strongest phosphomolybdenum reduction (140.56 g AA/100 g). Among the tested extracts, acetone extracts of M. trichocarpa showed maximum inhibition with 71.36 ±â€¯5.86%. In P. triflorum, chloroform extracts showed maximum inhibition (69.51%). The petroleum ether extract of M. trichocarpa was found to be most effective at which 50% mortality (LC50) and 90% mortality (LC90) of brine shrimp nauplii were found to be 29.22 and 184.82 mg/mL. This study results revealed the antioxidant and cytotoxic properties of P. triflorum and M. trichocarpa. Further investigations are needed to isolate and validate the active principles of the extract responsible various pharmacological properties.

Vertebrates as a Bactericidal Agent.

In Brazil, although a large number of animals are used in traditional medicine (at least 354 species), information about their biological activities is scarce. In this context, the objective of this study was to evaluate the bactericidal potential of zootherapeutic by-products from animals used in Brazilian traditional medicine and discuss the ecological and cultural consequences of such practices. The species analyzed were: Tupinambis merianae (skin), Iguana iguana (skin and body fat), Crotalus durissus (skin and body fat), Boa constrictor (skin), Euphractus sexcinctus (body fat) and Coendou prehensilis (quills). Experiments were performed with standard clinical strains of Escherichia coli (EC-ATCC10536) and Staphylococcus aureus (SA-ATCC 25923). For the microbiological assay, the zootherapeutics were evaluated using serial microdilutions. The results indicate that none of the samples possess inhibitory activity against standard bacterial strains. The in vitro ineffectiveness of the analyzed products demonstrate a necessity for new pharmacological research that encompass a large number of species of medicinal animals as well as highlight the importance of zootherapy in the context of plans for animal conservation.

Modulation of antibiotic effect by Fe2(MoO4)3 microstrutures.

In this study, we report the antibacterial activity and modulation of antibiotic activity by Fe2(MoO4)3 microstructures obtained by the hydrothermal route without use of surfactants or organic additives. This material was characterized by X-ray diffraction (XRD), Raman spectroscopy and scanning electron microscopy (SEM) images. The XRD pattern showed that the Fe2(MoO4)3 crystallize in a monoclinic structure without secondary phases. Raman spectroscopy confirms the formation of Fe2(MoO4)3. SEM images show that the Fe2(MoO4)3 obtained have ball-of-yarn shaped morphology. In the antibacterial assays, strains of Escherichia coli, Pseudomonas aeruginosa and Staphylococcus aureus were assayed by microdilution method to evaluate the antibacterial and modulatory-antibiotic activity with antibiotics as gentamicin, norfloxacin and imipenem. Against all bacteria, the Minimum Inhibitory Concentration (MIC) was Fe2(MoO4)3 ≥ 1024 µg/mL. This high MIC result must be associated with the fact of the iron be an essential microelement to the bacterial growth. However, when the Fe2(MoO4)3 was assayed in association with the antibiotics was observed an antagonistic effect demonstrated by an enhance of the MIC. This fact is associated directly with the pro-oxidative properties of metallic oxides. These compounds enhance the production of free radicals, as H2O2 and superoxide ions that can affect the cell structures as cell membrane and cell wall. Other effect is associated with the possible coordination of the metal, performing bonds with the chemical structure of the antibiotics, reducing their activity. Our results indicated that nanocompounds as Fe2(MoO4)3 can not be used as antimicrobial products for clinical usage, neither directly and neither in association with antibiotics.

Modulation of antibiotic activity by the hydroalcoholic extract from leaves of Caryocar coriaceum WITTM.

The aim of this study was to identify the presence of tannins, phenols and flavonoids on the hydroalcoholic extract of Caryocar coriaceum leaves (HECCL) and to determine the antioxidant and antibacterial activity of this extract. The extract was tested alone (1024-1 µg/mL) or associated (MIC/8) with several antibiotics in order to identify any antibacterial activity against multiresistant bacterial strains (Escherichia coli, Staphylococcus aureus and Pseudomonas aeruginosa). The existence of tannins, total phenols (901.31 mg/g) and flavonoids (89.68 mg/g) was confirmed in the HECCL. The presence of rutin and quercetin were confirmed by Thin-layer chromatography (TLC). Using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) method, the antioxidant activity of the extract (9 µg/mL) was determined. Moreover, the Minimum Inhibitory Concentration (MIC) value found for HECCL was 1024 µg/mL and the association between HECCL (MIC/8) with benzylpenicillin significantly changed its minimum inhibitory concentration from 2500 to 625 µg/mL against E. coli.

ß-Ag2MoO4 microcrystals: Characterization, antibacterial properties and modulation analysis of antibiotic activity.

This study reports the antibacterial properties and modulation analysis of antibiotic activity by ß-Ag2MoO4 microcrystals as well as their structural and vibrational characterization. The silver molybdate was obtained by the conventional hydrothermal method, and the structural, vibrational and morphological properties of the sample were determined using X-ray diffraction, Raman spectroscopy and scanning electron microscopy images. ß-Ag2MoO4 microcrystals obtained show spinel-type cubic structure (Fd-3m) with irregular shapes. The evaluation of antibacterial and modulatory-antibiotic activity was performed using the microdilution method to determine the Minimum Inhibitory Concentration (MIC) of the ß-Ag2MoO4 and antibiotics alone and associated with the silver molybdate. The ß-Ag2MoO4 modulates the antibiotic activity against all bacteria assayed in a synergistic (as the norfloxacin and gentamicin against S. aureus and gentamicin against E. coli) or an antagonistic form (as the norfloxacin against E.coli and P. aeruginosa). The reversion of antibiotic resistance by combinations with Ag2MoO4 could be a novel strategy to combat infections caused by multiple drug resistance (MDR) pathogens. Our results indicate that these silver molybdates present a clinically relevant antibacterial activity and enhanced the antibiotic activity of some antibiotics against MDR strain of S. aureus and E. coli, being an interesting alternative to combat antibiotic-resistant bacterial infectious agents.