Antibacterial and antioxidant activities of Licania tomentosa (Benth.) fritsch (crhysobalanaceae)

This work describes the chemical composition, and evaluates the antimicrobial and antioxidant activities of a hydroalcoholic extract from the leaves of the Licania tomentosa. Gram positive and negative bacterial strains were used in this work. Examination of the phytochemical composition of L. tomentosa revealed the presence of secondary metabolites such as tannins, flavonoids, saponins, alkaloids, steroids and triterpenoids. An antibacterial assay pointed out that the extract had a lower minimal inhibitory concentration (MIC - 32 μg/mL) towards Staphylococcus aureus (ATCC12692). The extract also presented antibacterial activity against other assayed bacteria, with the MIC varying between 64 and 512 μg/ mL. Our findings reveal that the extract presented an antioxidative capacity lower than that of BHT at the same concentration, used as positive control. Our results suggest that the levels and combinations between the secondary metabolites of this plant should be investigated to explain the demonstrated antibacterial activity

Potencial terapêutico e uso de plantas medicinais em uma área de Caatinga no estado do Ceará, nordeste do Brasil

O presente trabalho visou o levantamento etnobotânico das plantas medicinais, verificando a versatilidade das espécies utilizadas e o consenso de uso e/ou conhecimento entre os informantes, do Distrito de Aratama, no Município de Assaré, Ceará. As informações etnobotânicas foram obtidas através de entrevistas estruturadas e semi-estruturadas com os moradores locais. Foram citadas 116 espécies com fins medicinais pertencentes a 103 gêneros e 58 famílias com destaque para Fabaceae (10ssp.), Asteraceae (7spp.) e Lamiaceae (6spp.). Entre as espécies levantadas, Mentha spicata L., Rosmarinus officinalis L., Allium sativum L., Bauhinia cheilantha (Bong.), Ximenea americana L., se destacaram como as mais versáteis dentro da comunidade. As indicações terapêuticas citadas foram agrupadas em 16 categorias de sistemas corporais, dos quais as Desordens mentais e comportamentais, as Afecções ou dores não definidas, os Transtornos do sistema respiratório, as Doenças de pele e do tecido celular subcutâneo, e os Transtornos do sistema sensorial (ouvidos), mostram maior concordância entre os informantes na utilização de espécies para tratar um sistema corporal especifico. Os resultados mostraram elevada riqueza da flora medicinal presente na caatinga. Neste sentido, torna-se necessária a intensificação de estudos que avaliem e consolidem as propriedades químicas e farmacológicas destas espécies

Essential oil of Lippia alba and its main constituent citral block the excitability of rat sciatic nerves

Lippia alba is empirically used for infusions, teas, macerates, and hydroalcoholic extracts because of its antispasmodic, analgesic, sedative, and anxiolytic effects. Citral is a mixture of trans-geranial and cis-neral and is the main constituent of L. alba essential oil and possesses analgesic, anxiolytic, anticonvulsant, and sedative effects. The present study evaluated the effects of the essential oil of L. alba (EOLa) and citral on compound action potentials (CAPs) in Wistar rat sciatic nerves. Both drugs inhibited CAP in a concentration-dependent manner. The calculated half-maximal inhibitory concentrations (IC50) of peak-to-peak amplitude were 53.2 µg/mL and 35.00 µg/mL (or 230 µM) for EOLa and citral, respectively. Peak-to-peak amplitude of the CAP was significantly reduced by 30 µg/mL EOLa and 10 µg/mL citral. EOLa and citral (at 60 and 30 µg/mL, values close to their respective IC50 for CAP blockade) significantly increased chronaxy and rheobase. The conduction velocity of the first and second CAP components was statistically reduced to ∼86% of control with 10 µg/mL EOLa and ∼90% of control with 3 µg/mL citral. This study showed that EOLa inhibited nerve excitability and this effect can be explained by the presence of citral in its composition. Both EOLa and citral showed inhibitory actions at lower concentrations compared with other essential oils and constituents with local anesthetic activity. In conclusion, these data demonstrate that EOLa and citral are promising agents in the development of new drugs with local anesthetic activity

Antiedematogenic and anti-inflammatory activity of the monoterpene isopulegol and its β-cyclodextrin (β-CD) inclusion complex in animal inflammation models

Isopulegol (ISO) is an alcoholic monoterpene widely found in different plant species, such as Melissa officinalis, and has already been reported to have a number of pharmacological properties. Like other terpenes, ISO is a highly volatile compound that is slightly soluble in water, so its inclusion into cyclodextrins (CDs) is an interesting approach to increase its solubility and bioavailability. Thus, our aim was to evaluate the antiedematogenic and anti-inflammatory activity of isopulegol and a \u3b2-cyclodextrin-isopulegol inclusion complex (ISO/\u3b2-CD) in rodent models. For the anti-inflammatory activity evaluation, antiedematogenic plethysmometry and acute (peritonitis and pleurisy), as well as chronic (cotton pellet-induced granuloma) anti-inflammatory models, were used. The docking procedure is used to evaluate, analyze, and predict their binding mode of interaction with H1 and Cox-2 receptors. The animals (n = 6) were divided into groups: ISO and ISO/\u3b2-CD, negative control (saline), and positive control (indomethacin and promethazine). ISO and ISO/\u3b2-CD were able to reduce acute inflammatory activity by decreasing albumin extravasation, leukocyte migration, and MPO concentration, and reducing exudate levels of IL-1\u3b2 and TNF-\u3b1. ISO and ISO/\u3b2-CD significantly inhibited edematogenic activity in carrageenan- and dextran-induced paw edema. Moreover, both significantly reduced chronic inflammatory processes, given the lower weight and protein concentration of granulomas in the foreign body granulomatous inflammation model. The results suggest that the inclusion of ISO in \u3b2-cyclodextrins improves its pharmacological properties, with the histamine and prostaglandin pathways as probable mechanisms of inhibition, and also reinforces the anti-inflammatory profile of this terpene

Relaxant Effect of Monoterpene (-)-Carveol on Isolated Human Umbilical Cord Arteries and the Involvement of Ion Channels

Carveol is a monoterpene present in the structure of many plant products. It has a variety of biological activities: antioxidant, anticancer and vasorelaxation. However, studies investigating the effect of monoterpenoids on human vessels have not yet been described. Thus, the present study aimed to characterize the effect of (-)-carveol on human umbilical arteries (HUAs). HUA ring preparations were isolated and subjected to isometric tension recordings of umbilical artery smooth muscle contractions. (-)-Carveol exhibited a significant vasorelaxant effect on KCl and 5-HT-induced contractions, obtaining EC50 values of 344.25 \ub1 8.4 and 175.82 \ub1 4.05 \ub5M, respectively. The participation of calcium channels in the relaxation produced by (-)-carveol was analyzed using vessels pre-incubated with (-)-carveol (2000 \ub5M) in a calcium-free medium, where the induction of contractions was abolished. The vasorelaxant effect of (-)-carveol on HUAs was reduced by tetraethylammonium (TEA), which increased the (-)-carveol EC50 to 484.87 \ub1 6.55 \ub5M. The present study revealed that (-)-carveol possesses a vasorelaxant activity in HUAs, which was dependent on the opening of calcium and potassium channels. These results pave the way for further studies involving the use of monoterpenoids for the vasodilatation of HUAs. These molecules have the potential to treat diseases such as pre-eclampsia, which is characterized by resistance in umbilical arteries

Anti-inflammatory and physicochemical characterization of the croton rhamnifolioides essential oil inclusion complex in β-cyclodextrin

Croton rhamnifolioides is used in popular medicine for the treatment of inflammatory diseases. The objective of this study was to characterize and evaluate the anti-inflammatory effect of C. rhamnifolioides essential oil complexed in \u3b2-cyclodextrin (COEFC). The physicochemical characterization of the complexes was performed using different physical methods. The anti-inflammatory activity was evaluated in vivo by ear edema, paw edema, cotton pellet-induced granuloma, and vascular permeability by Evans blue extravasation. The mechanism of action was validated by molecular docking of the major constituent into the cyclooxygenase-2 (COX-2 enzyme). All doses of the COEFC reduced acute paw edema induced by carrageenan and dextran, as well as vascular permeability. Our results suggest the lowest effective dose of all samples inhibited the response induced by histamine or arachidonic acid as well as the granuloma formation. The complexation process showed that the pharmacological effects were maintained, however, showing similar results using much lower doses. The results demonstrated an involvement of the inhibition of pathways dependent on eicosanoids and histamine. Complexation of \u3b2-cyclodextrin/Essential oil (\u3b2-CD/EO) may present an important tool in the study of new compounds for the development of anti-inflammatory drugs

GC-MS profile and enhancement of antibiotic activity by the essential oil of ocotea odorífera and safrole: Inhibition of staphylococcus aureus efflux pumps

Considering the evidence that essential oils, as well as safrole, could modulate bacterial growth in different resistant strains, this study aims to characterize the phytochemical profile and evaluate the antibacterial and antibiotic-modulating properties of the essential oil Ocotea odor\uedfera (EOOO) and safrole against efflux pump (EP)-carrying strains. The EOOO was extracted by hydrodistillation, and the phytochemical analysis was performed by gas chromatography coupled to mass spectrometry (GC-MS). The antibacterial and antibiotic-modulating activities of the EOOO and safrole against resistant strains of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa were analyzed through the broth microdilution method. The EP-inhibiting potential of safrole in association with ethidium bromide or antibiotics was evaluated using the S. aureus 1199B and K2068 strains, which carry genes encoding efflux proteins associated with antibiotic resistance to norfloxacin and ciprofloxacin, respectively. A reduction in the MIC of ethidium bromide or antibiotics was used as a parameter of EP inhibition. The phytochemical analysis identified 16 different compounds in the EOOO including safrole as the principal constituent. While the EOOO and safrole exerted clinically relevant antibacterial effects against S. aureus only, they potentiated the antibacterial activity of norfloxacin against all strains evaluated by our study. The ethidium bromide and antibiotic assays using the strains of S. aureus SA1119B and K2068, as well as molecular docking analysis, indicated that safrole inhibits the NorA and MepA efflux pumps in S.aureus. In conclusion, Ocotea odorifera and safrole presented promising antibacterial and antibiotic-enhancing properties, which should be explored in the development of drugs to combat antibacterial resistance, especially in strains bearing genes encoding efflux proteins

Effect of α-bisabolol and its β-cyclodextrin complex as TetK and NorA efflux pump inhibitors in Staphylococcus aureus strains

Efflux pumps are proteins present in the plasma membrane of bacteria, which transport antibiotics and other compounds into the extracellular medium, conferring resistance. The discovery of natural efflux pump inhibitors is a promising alternative. \u3b1-Bisabolol is a sesquiterpene isolated from several plants such as Matricaria chamomilla L. and has important properties such as antibacterial and anti-inflammatory activity. Currently, the formation of inclusion complexes with \u3b2-Cyclodextrin has been used for improving the physicochemical characteristics of the host molecule. This study evaluated the effect of \u3b1-Bisabolol, in isolation and in complexation with \u3b2-Cyclodextrin, as TetK and NorA efflux pump inhibitors in Staphylococcus aureus strains. The minimum inhibitory concentration (MIC) was determined. Subsequently, inhibitory activity over the pumps was observed by an MIC reduction for the antibiotics, by using subinhibitory concentrations (MIC/8) in combination with tetracycline and norfloxacin. The MIC of the compounds was 651024 \u3bcg/mL. \u3b1-Bisabolol potentiated the action of tetracycline and reduced the MIC of norfloxacin to a clinically relevant concentration. The complexed substance showed synergism however, the effect of the isolated \u3b1-Bisabolol was superior to the complex. These results indicate \u3b1-Bisabolol is a potential substance to be used as an efflux pump inhibitor

Possible involvement of transcriptional activation of nuclear factor erythroid 2-related factor 2 (Nrf2) in the protective effect of caffeic acid on paraquat-induced oxidative damage in Drosophila melanogaster

Paraquat (PQ) is a widely used herbicide with no antidote which is implicated in the pathogenesis of the Parkinson's disease. The present study then investigated the potential of caffeic acid (CA), a known antioxidant, cardioprotective and neuroprotective molecule to counteract oxidative stress mediated by PQ. In addition, molecular docking was performed to understand the mechanism underlying the inhibitory effect of CA against PQ poisoning. The fruit fly, Drosophila melanogaster, was exposed to PQ (0.44 mg/g of diet) in the absence or presence of CA (0.25, 0.5, 1 and 2 mg/g of died) for 7 days. Data showed that PQ-fed flies had higher incidence of mortality which was associated with mitochondrial dysfunction, increased free Fe(II) content and lipid peroxidation when compared to the control. Co-exposure with CA reduced mortality and markedly attenuated biochemical changes induced by PQ. The mechanism investigated using molecular docking revealed a strong interaction (−6.2 Kcal/mol) of CA with D. melanogaster transcriptional activation of nuclear factor erythroid 2-related factor 2 (Nrf2). This was characterized by the binding of CA to keap-1 domain of Nrf2. Taking together these results indicate the protective effect of CA against PQ-induced oxidative damage in D. melanogaster was likely through its coordination which hinders Nrf2-keap-1 binding leading to an increase of the antioxidant defense system