Synthesis and antibacterial activity of a new derivative of the meldrun acid: 2,2-dimethyl-5-(4H-1,2,4-triazol-4-ylaminomethylene)-1,3-dioxane-4,6-dione (C9H10N4O4)

The discovery of new substances with proven antimicrobial activity is the current study goal of various researchers. Usage of synthetic products has grown considerably in the past few years due to processing agility, and capability of going through previous chemical modifications in order to enhance its biological activity. Widespread careless use of antimicrobials has made the number of resistant microorganisms rise significantly, thus demanding more efficient drugs to fight them. One of these synthetic candidates for this purpose is the substance 2,2-Dimethyl-5-(4H-1,2,4-triazol-4-ylaminomethylene)-1,3-dioxane-4,6-dione (C9H10N4O4), aminomethylene derivative from Meldrum's acid. This substance, alone and in association with common antibiotics, were evaluated in vitro for antimicrobial activity, and had their minimum inhibitory concentration (MIC) towards Staphylococcus aureus ATCC 25923, Escherichia coli ATCC 10536 and Pseudomonas aeruginosa ATCC 15442, as well as multiresistant strains Escherichia coli 27, Staphylococcus aureus 358 and Pseudomonas aeruginosa 03 determined. The antimicrobial modulation action tests of the aminoglycosides with C9H10N4O4 were performed according to the microdilution method, and resulted in observation of a positive synergic effect

Modulatory antimicrobial activity of Piper arboretum extracts (Zingiberaceae)

The side effects of certain antibiotics have been a recent dilemma in the medical arena. Due this fact, the necessity of natural product discovery could provide important indications against several pharmacological targets and combat many infectious agents. Piper arboreum Aub. (Piperaceae) has been used by Brazilian traditional communities against several illnesses including rheumatism, bronchitis, sexually transmitted diseases and complaints of the urinary tract. Medicinal plants are a source of several remedies used in clinical practice to combat microbial infections. In this study, ethanol extract and fractions of Piper arboreum leaves were used to assay antimicrobial and modulatory activity. The minimum inhibitory concentration (MIC) was determined using microdilution method of ethanol extract and fractions from the leaves of P. arboreum ranging between 8 and 1024 mgmL–1. The capacity of these natural products to enhance the activity of antibiotic and antifungal drugs was also assayed. In these tests, natural products were combined with drugs. The natural products assayed did not demonstrate any clinically relevant antimicrobial activity (MIC ³ 1024 mg mL–1). However, the modulation of antibiotic activity assay observed a synergistic activity of natural products combined with antifungal (such as nystatin and amphotericin B) and antibiotic drugs (such as amikacin, gentamicin and kanamycin). According to these results, these natural products can be an interesting alternative not only to combat infectious diseases caused by bacteria or fungi, but also to combat enhanced resistance of microorganisms to antibiotic and antifungal drugs

Atividade antimicrobiana e efeito combinado sobre drogas antifúngicas e antibacterianas do fruto de Morinda citrifolia L

La aparición de microorganismos resistentes y la toxicidad asociada a los antimicrobianos aumenta la necesidad de investigar nuevos principios activos. Morinda citrifolia L., es una planta fructífera utilizada popularmente como antibacteriano y con otros diversos usos farmacológicos. Posee diversos metabolitos primarios y secundarios, principalmente flavonoides, triterpenoides y alcaloides. Este estudio tuvo como objetivo ensayar la potencial actividad antimicrobiana y moduladora de los extractos obtenidos de su fruta. Los extractos de las frutas fueron testados tanto para determinar el efecto antimicrobiano como también utilizándolo en combinación con agentes antibacterianos y antifúngicos contra microorganismos patógenos, por el método de microdilución en caldo. Se observó que la asociación entre antibióticos y extractos dió resultados clínicamente significativos en pruebas con bacterias Pseudomonas aeruginosa y Escherichia coli.The rising of the drug resistant microrganisms and the toxicity related with the antimicrobial drugs enhances the necessity about the search of new bioactive compounds. Morinda citrifolia L. is a fruit tree traditionally used as antibacterial and with several other pharmacological properties. This plant presents several phytocompounds as flavonoids, alkaloids and triterpenes. The objective of this work was assay the antimicrobial and modulatory potential of the fruit extract. The extract was assayed alone and associated with antibiotics and antifungals against pathogenic microrganisms using the microdilution assay. The results demonstrated that the association between extract and antimicrobial drugs resulted in a potentiation of the drug activity clinically relevant against Pseudomonas aeruginosa and Escherichia coli.The surveillance of resistant microrganisms and the toxicity related with antimicrobial drugs enhances the necessity of research about new remedies. Morinda citrifolia is a plant commonly used as antibacterial, analgesic, and several other bioactivities, presenting aminoacids, anthraquinones, flavonoids, sterols, triterpenes and alkaloids. The aim of this work was evaluate the antimicrobial and the antibiotic-modulatory effect of the fruit extract. The extract was assayed alone and in association with antibiotic and antifungal drugs against clinical isolates by microdilution method. The fruit extract of M. citrifolia demonstrate an interesting modulatory activity, enhancing the effect of the assayed antibiotics against P. aeroginosa and E. coli, but not against Candida strains

Cytoprotective Effect of Lygodium venustum

Mercury is a very dangerous metal when humans come into contact with it, whether through the air or skin or by ingestion. The aim of this work was to investigate the possible effects of the ethanol extract and fractions of Lygodium venustum Sw. against mercurium chloride toxicity towards Escherichia coli strain ATCC25922. The polyphenols and flavonoids present in the extract and fractions were quantified in mg equivalent of gallic acid/g sample and mg equivalent of quercetin/g sample, respectively. The in vitro FRAP method demonstrated the antioxidant activity of the samples. The antibacterial activity of the natural products was evaluated by microdilution method and by assays to elucidate the possible cytoprotective action when combining the natural products samples and mercurium chloride, utilizing the extract and fractions at a subinhibitory concentration. The results obtained in this work indicate that the ethanol extract and fractions of L. venustum are an alternative source of natural products with cytoprotective action, where this protection is correlated with antioxidant and chelating activity, due to the presence of total phenols and flavonoids

Evaluation of the Antimicrobial Activity of the Decoction of Tropidurus hispidus (Spix, 1825) and Tropidurus semitaeniatus (Spix, 1825) Used by the Traditional Medicine

Tropidurus hispidus and Tropidurus semitaeniatus are two lizard species utilized in traditional medicine in Northeast Brazil. Their medicinal use includes diseases related with bacterial infections such as tonsillitis and pharyngitis. They are used in the form of teas (decoctions) for the treatment of illnesses. In this work, we evaluated the antimicrobial activity of the decoctions of T. hispidus (DTH) and T. semitaeniatus (DTS) against bacterial strains, namely, standard and multiresistant Escherichia coli, Staphylococus aureus, and Pseudomonas aureuginosa, alone and in combination with aminoglycoside antibiotics. The decoctions were prepared using the whole body of the dried lizards, and the filtrate was frozen and lyophilized. When tested alone, the samples did not demonstrate any substantial inhibition of bacterial growth. However, in combination with antibiotics as aminoglycosides, decoctions reduced the minimal inhibitory concentration (MIC) of the assayed antibiotics against multiresistant strains of S. aureus and P. aureuginosa. Chemical prospecting tests revealed the presence of alkaloids in DTS. This is the first study evaluating the medicinal efficacy of T. hispidus and T. semitaeniatus and contributes to the list of new sources of medicines from natural products of animal origin

HPLC-DAD analysis, antinociceptive and anti-inflammatory properties of the ethanolic extract of Hyptis umbrosa in mice

Hyptis umbrosa (syn. Mesosphaerum sidifolium) (Lamiaceae Family) has been used to treat several conditions such as gastrointestinal disorders, skin infections, nasal congestion, fever and cramps. The objective of this study was to evaluate the chemical composition, analgesic and anti-inflammatory profiles of ethanol extract from leaves of Hyptis umbrosa (EEB). HPLC-DAD was used to determine the fingerprint chromatogram of the extract. Male Swiss mice were orally pretreated with EEB (100, 200 or 400 mg/kg; 60 min before initiating algesic stimulation) and antinociceptive activity was assessed using the acetic acid-induced writhing model, formalin test and hyperalgesia induced by glutamate or capsaicin. Also, peritonitis was induced by the intrathoracic injection of carrageenan to quantify the total number of leukocytes. The presence of phenolic compounds in the extract was confirmed using HPLC-DAD. The treatment with EEB, at all doses, produced a significant analgesic effect against acetic acid-induced antinociceptive activity. In the formalin test, only the 400-mg/kg-dose of EEB had a significant effect in the first phase. However, all doses tested were able to reverse nociception in the second phase. The effect of all doses of EEB also showed a significant antinociceptive effect in the glutamate and capsaicin tests and inhibited the carrageenan-induced leukocyte migration to the peritoneal cavity. The present study suggests that the EEB possesses peripheral analgesic action and showed potential in reducing the spreading of the inflammatory processes. Also, it seems to be related with vanilloid and glutamate receptors

Cytoprotective Effect of Lygodium venustum Sw. (Lygodiaceae) against Mercurium Chloride Toxicity

Mercury is a very dangerous metal when humans come into contact with it, whether through the air or skin or by ingestion. The aim of this work was to investigate the possible effects of the ethanol extract and fractions of Lygodium venustum Sw. against mercurium chloride toxicity towards Escherichia coli strain ATCC25922. The polyphenols and flavonoids present in the extract and fractions were quantified in mg equivalent of gallic acid/g sample and mg equivalent of quercetin/g sample, respectively. The in vitro FRAP method demonstrated the antioxidant activity of the samples. The antibacterial activity of the natural products was evaluated by microdilution method and by assays to elucidate the possible cytoprotective action when combining the natural products samples and mercurium chloride, utilizing the extract and fractions at a subinhibitory concentration. The results obtained in this work indicate that the ethanol extract and fractions of L. venustum are an alternative source of natural products with cytoprotective action, where this protection is correlated with antioxidant and chelating activity, due to the presence of total phenols and flavonoids

Herbal therapy associated with antibiotic therapy: potentiation of the antibiotic activity against methicillin – resistant Staphylococcus aureus by Turnera ulmifolia L

<p>Abstract</p> <p>Background</p> <p><it>Staphylococcus </it>genus is widely spread in nature being part of the indigenous microbiota of skin and mucosa of animal and birds. Some <it>Staphylococcus </it>species are frequently recognized as etiological agents of many animal and human opportunistic infections This is the first report testing the antibiotic resistance-modifying activity of <it>Turnera ulmifolia </it>against methicillin-resistant <it>Staphylococcus aureus </it>– MRSA strain.</p> <p>Methods</p> <p>In this study an ethanol extract of <it>Turnera ulmifolia </it>L. and chlorpromazine were tested for their antimicrobial activity alone or in combination with aminoglycosides against an MRSA strain.</p> <p>Results</p> <p>The synergism of the ethanol extract and aminoglycosides were verified using microdillution method. A synergistic effect of this extract on gentamicin and kanamycin was demonstrated. Similarly, a potentiating effect of chlorpromazine on kanamycin, gentamicin and neomycin, indicating the involvement of an efflux system in the resistance to these aminoglycosides.</p> <p>Conclusion</p> <p>It is therefore suggested that extracts from <it>Turnera ulmifolia </it>could be used as a source of plant-derived natural products with resistance-modifying activity, constituting a new weapon against the problem of bacterial resistance to antibiotics demonstrated in MRSA strains.</p