Henrique Douglas

Bio: Henrique Douglas is an academic researcher. The author has contributed to research in topics: Essential oil & Acinetobacter. The author has an hindex of 4, co-authored 7 publications receiving 75 citations.

The genus Cordia: botanists, ethno, chemical and pharmacological

Abstract: Species of the genus Cordia, Boraginaceae, are widely studied with regard to the various ethnobotanicaland ethnopharmacological aspects. They are found principally in tropical and subtropical regions of theAmerican,AsianandAfricancontinents,wheretheyoccurinvariouscountries.InthegenusCordia,thereare many species cultivated for ornamental plants, wood and medicinal applications, where they areextensively utilized by traditional communities. In the last decades, scientific studies of Cordia specieshaveintensified,demonstratingthegreatinterestinphytochemical,biologicalandpharmacologicalstud-ies. In this review, we describe the principal botanical aspects, ethnopharmacological information andevaluation ofthebioactiveandpharmacologicalpropertiesofCordia,itsphytochemicalconstituentsandthe most common classes of secondary metabolites identified. The information reported in this workcontributes scientifically to recognizing the importance of the genus Cordia as a target in the search fornew biotechnological investments.© 2015 Sociedade Brasileira de Farmacognosia. Published by Elsevier Editora Ltda. All rights reserved.

Original article: ACTION OF CHOLECALCIFEROL AND ALPHA-TOCOPHEROL ON STAPHYLOCOCCUS AUREUS EFFLUX PUMPS

Abstract: Alpha-tocopherol is one the most abundant and biologically active isoforms of vitamin E. This compound is a potent antioxidant and one of most studied isoforms of vitamin E. Vitamin D3 (cholecalciferol) is an important nutrient for calcium homeostasis and bone health, that has also been recognized as a potent modulator of the immune response. Methicillin-resistant Staphylococcus aureus (MRSA) is the most important causative agent of both nosocomial and community-acquired infections. The aim of this study was to evaluate the inhibitory effect of alpha-tocopherol and cholecalciferol on both S. aureus and multidrug resistant S. aureus efflux pumps. The RN4220 strain has the plasmid pUL5054 that is the carrier of gene that encodes the macrolide resistance protein (an efflux pump) MsrA; the IS-58 strain possesses the TetK tetracycline efflux protein in its genome and the 1199B strain resists to hydrophilic fluoroquinolones via a NorA-mediated mechanism. The antibacterial activity was evaluated by determining the Minimal Inhibitory Concentration (MIC) and a possible inhibition of efflux pumps was associated to a reduction of the MIC. In this work we observed that in the presence of the treatments there was a decrease in the MIC for the RN4220 and IS-58 strains, suggesting that the substances presented an inhibitory effect on the efflux pumps of these strains. Significant efforts have been done to identify efflux pump inhibitors (EPIs) from natural sources and, therefore, the antibacterial properties of cholecalciferol and alphatocopherol might be attributed to a direct effect on the bacterial cell depending on their amphipathic structure.

PHCOG MAG.: Research Article Antiulcer and antimicrobial activities of Stryphnodendron rotundifolium Mart.

Abstract: The ethanolic extract of Stryphnodendron rotundifolium stem bark (EESR) was investigated for therapeutic properties using ethanol-induced ulceration in mice. Antimicrobial and preliminary phytochemical screening of the extract was also investigated. The extract (200-400 mg/kg p.o.) dose dependently reduced ethanol (0.2 mL/animal p.o.) - induced ulceration in mice. EESR showed antimicrobial activity against five bacterial species (Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, Shigella flexineri, Staphylococcus epidermidis) but not against the fungi Aspergillus niger . The above results show that Stryphnodendron rotundifolium bark probably contains some active ingredients that could be developed for health problems as have been claimed by traditional popular use. KEY WORDS. Stryphnodendron rotundifolium ; ethanolic extract; antiulcer; antimicrobial activity. INTRODUCTION Plants are potent biochemists and have been components of phytomedicine since times immemorial (1). The beneficial medicinal effects of plant materials typically result from the combinations of secondary products present in the plant. The medicinal actions of plants are unique to particular plant species or groups are consistent with this concept as the combination of secondary products in a particular plant is taxonomically distinct (2). The genus Stryphnodendron Mart., family Leguminosae, includes about 48 species, all native to central savannas of Brazil, including Stryphnodendron obovatum Benth. (3). The stem bark of several species of Stryphnodendron, which contains about 20% tannins, is used by the local population for wound healing and treatment of leukorrhea and diarrhoea (4). Tannin-rich plants are used in folk medicine because of their antimicrobial properties, and act as scavengers of free radicals (4). Stryphnodendron rotundifoloium (Leguminoseae) popularly know as “Barbatimao” is a typical tree of Cariri Region, Ceara State, Brazil (5). Phytochemical analysis of the ethanol extract of stem bark of “barbatimao” allowed the identification and isolation of tannins and flavonoids. Their barks have been used in folk medicine as cicatrizant and for that reason your biological activity probably can be attributed to the high content of tannins (c.a. 40%) (6,7). In view of the popular use of extracts of Stryphnodendron rotundifoloium, the present study was undertaken to investigate the effect of the ethanolic extract of "barbatimao" stem bark (EESR) on ethanol-induced gastric ulcers and its antimicrobial activity. MATERIAL AND METHODS Plant material. Plant material of S. rotundifolium was collected in September 2005, in line D of the National Forest Araripe, Crato, Ceara State, Brazil. A voucher specimen (# 33621) is deposited at the Herbarium Prisco Bezerra, Universidade Federal do Ceara. Ethanolic bark extract. Dried and powdered stem bark of S. rotundifolium (1.7 Kg) was exhaustively extracted with EtOH at room temperature. The EtOH stem bark extract was dried under reduced pressure to yield (183 g). Animals . Experiments were performed in male Swiss mice (20 – 25 g) obtained from the Central Animal House of this University. They were housed at 22 ± 2

CHEMICAL COMPOSITION AND ANTIMICROBIAL ACTIVITY OF Cinnamomum zeylanicum Blume ESSENTIAL OIL ON MULTI-DRUG RESISTANT Acinetobacter spp. strains

Abstract: The genus Acinetobacter comprises a group of Gram-negative bacteria and non- fermenters of glucose that are important nosocomial pathogens, many of which being resistant to many antimicrobial agents. Studies on the antibacterial activity of new products have been conducted, including the essential oils. The essential oil analysis resulted in the identification of five components with eugenol as the major component. The essential oil at 625 µg/ml concentration produced inhibition on the growth of 71% strains of Acinetobacter and the MBC was established as 1250 µg/mL. It was observed from the time kill experiment that the essential oil of Cinnamomum zeylanicum has concentration-dependent bactericidal activity. The results of this study have shown the antibacterial potential of the essential oil and may lead to future researches on this essential oil or your chemical constituents, aiming its possible clinical application in the treatment of infections caused by multi drug resistant Acinetobacter species.

Antibacterial activity of the essential oil of Citrus limon against multidrug resistant Acinetobacter strains

Abstract: Actinetobacter species have gained importance in recent years due to their involvement in serious infections and anti microbial resistance. New products with antibacterial activit y have been studied including the essential oil (EO ) of Citrus limon . The present study aimed to evaluate the effect of the e ssential oil of C. limon against multidrug resistant strains of Acinetobacter spp. isolated from clinical material. The Minimum I nhibitory Concentration (MIC) and Minimum Bactericidal Concentration (MBC) were determined by the microplate bioassay, and a time kill study of Acinetobacter spp . treated with EO, was performed. The oil caused the growth inhibition in 16 (67%) of 24 strains tested, showing a MIC of 625 µg/mL and MBC of 1250 µg/mL. In a time kill study, the oil displayed a concentration-dependent antibacterial activity. These results suggest that EO of C. limon may suppress the growth of Acinetobacter species.

Efflux pump inhibitors for bacterial pathogens: From bench to bedside.

Abstract: With the advent of antibiotics, bacterial infections were supposed to be a thing of past. However, this instead led to the selection and evolution of bacteria with mechanisms to counter the action of antibiotics. Antibiotic efflux is one of the major mechanisms, whereby bacteria pump out the antibiotics from their cellular interior to the external environment using special transporter proteins called efflux pumps. Inhibiting these pumps seems to be an attractive strategy at a time when novel antibiotic supplies are dwindling. Molecules capable of inhibiting these pumps, known as efflux pump inhibitors (EPIs), have been viewed as potential therapeutic agents that can rejuvenate the activity of antibiotics that are no longer effective against bacterial pathogens. EPIs follow some general mechanisms of efflux inhibition and are derived from various natural as well as synthetic sources. This review focuses on EPIs and identifies the challenges that have kept these futuristic therapeutics away from the commercial realm so far.

Traditional uses, phytochemistry and pharmacology of the medicinal species of the genus Cordia (Boraginaceae).

Abstract: Objectives Cordia (family Boraginaceae) is a genus of deciduous flowering trees or shrubs comprising more than 300 species distributed widely in the tropical regions. The aim of this review was to provide exhaustive scientific information on traditional uses, phytochemistry and pharmacological activities of the 36 important species with medicinal value from the genus Cordia, to divulge prospects for further research on its therapeutic potential. Key findings Leaves, fruit, bark and seed of a majority of the species were found to possess abundant ethnomedicinal value, but leaves were found to be used most frequently to treat many ailments such as respiratory disorders, stomach pain, wound, inflammation, myalgia, cough, dysentery and diarrhoea. The phytochemical investigation of 36 species resulted in isolation of 293 chemical constituents from various chemical classes. The crude extracts, fractions, essential oils and pure compounds isolated from various Cordia species were reported to have a varied range of pharmacological activities. Summary Many of the traditional uses of the genus Cordia were supported by the results obtained from pharmacological studies performed using various extracts or pure compounds. More attention should be given to the biological evaluation using pure phytochemicals and to identify the mechanism of actions and exploring this genus for new drug discovery.

The Role of Drug Repurposing in the Development of Novel Antimicrobial Drugs: Non-Antibiotic Pharmacological Agents as Quorum Sensing-Inhibitors.

Abstract: Background: The emergence of multidrug-resistant organisms (MDROs) is a global public health issue, severely hindering clinicians in administering appropriate antimicrobial therapy. Drug repurposing is a drug development strategy, during which new pharmacological applications are identified for already approved drugs. From the viewpoint of the development of virulence inhibitors, inhibition of quorum sensing (QS) is a promising route because various important features in bacterial physiology and virulence are mediated by QS-dependent gene expression. Methods: Forty-five pharmacological agents, encompassing a wide variety of different chemical structures and mechanisms of action, were tested during our experiments. The antibacterial activity of the compounds was tested using the broth microdilution method. Screening and semi-quantitative assessment of QS-inhibition by the compounds was performed using QS-signal molecule-producing and indicator strains. Results: Fourteen pharmaceutical agents showed antibacterial activity in the tested concentration range, while eight drugs (namely 5-fluorouracil, metamizole-sodium, cisplatin, methotrexate, bleomycin, promethazine, chlorpromazine, and thioridazine) showed dose-dependent QS-inhibitory activity in the in vitro model systems applied during the experiments. Conclusions: Virulence inhibitors represent an attractive alternative strategy to combat bacterial pathogens more efficiently. Some of the tested compounds could be considered potential QS-inhibitory agents, warranting further experiments involving additional model systems to establish the extent of their efficacy.