We describe here the extraction and identification of several classes of phenolic compounds from the lichens
Parmotrema dilatatum (Vain.) Hale,
Parmotrema tinctorum (Nyl.) Hale,
Pseudoparmelia ...sphaerospora (Nyl.) Hale and
Usnea subcavata (Motyka) and determined their anti-tubercular activity. The depsides (atranorin, diffractaic and lecanoric acids), depsidones (protocetraric, salazinic, hypostictic and norstictic acids), xanthones (lichexanthone and secalonic acid), and usnic acid, as well seven orsellinic acid esters, five salazinic acid 8’,9’-
O-alkyl derivatives and four lichexanthone derivatives, were evaluated for their activity against
Mycobacterium tuberculosis. Diffractaic acid was the most active compound (MIC value 15.6
μg/ml, 41.6
μM), followed by norstictic acid (MIC value 62.5
μg/ml, 168
μM) and usnic acid (MIC value 62.5
μg/ml, 182
μM). Hypostictic acid (MIC value 94.0
μg/ml, 251
μM) and protocetraric acid (MIC value 125
μg/ml, 334
μM) showed moderate inhibitory activity. The other compounds showed lower inhibitory activity on the growth of
M. tuberculosis, varying from MIC values of 250 to 1370
μM.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK
Gallic acid and its derivatives are phenolic compounds widely used as food supplements in the form of capsules, liquid extracts, and ointments owing to their good antioxidant properties. Besides, ...these compounds are potent inhibitors of fungi, bacteria, and some viruses and possess strong antiproliferative and chemopreventive activities. However, gallic acid derivatives are also known to exert harmful effects like mutagenicity and cytotoxicity. The present study aimed to understand and explore the toxicological risks of these compounds. For this, a series of alkyl gallates with side chains varying from five to eight carbons (pentyl, hexyl, heptyl, and octyl gallates) were evaluated for their cytotoxic and pro-apoptotic potential. In addition, the genotoxic effects of alkyl gallates were measured in HepG2 cells using the single cell gel electrophoresis (SCGE)/comet assay and the cytokinesis-blocked micronucleus (CBMN) test. In both the tests, the substances did not induce any significant differences when compared to the control group. In addition, alkyl gallates exhibited a chemopreventive effect, thereby considerably reducing the mutagenicity caused by H2O2. In conclusion, our results suggest that alkyl gallates are non-genotoxic, non-mutagenic, and pro-apoptotic agents, which may serve as suitable and promising candidates for preventing chemically-induced chromosomal damage.
•Alkyl gallates promoted apoptosis in HepG2 cells.•No mutagenic (micronucleus test) and genotoxic effects (comet assays) were observed in the cells exposed to alkyl gallates.•Alkyl gallates protected DNA against H2O2 damage in HepG2.
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Copaiba oleoresin has been used in folk medicine in the treatment of bronchitis, syphilis, skin diseases and ulcers due to its anti-inflammatory and antiseptic activities, but there is no information ...about major compounds oral absorption to support the traditional use.
Considering the potential of copalic (CA) and kaurenoic acid (KA) – major biological activity (in vitro) diterpenes found in the oleoresin, this study aimed to evaluate the intestinal permeability of CA and KA using Caco-2 cells model as predictive test for oral drug absorption.
Chemical stability at pH 1.2 and 7.4 and plasma stability were evaluated to mimic physiological conditions of the gastrointestinal tract. The intestinal permeability of CA and KA was evaluated in Caco-2 cells in the presence and absence of the P-glycoprotein inhibitor verapamil.
CA and KA were rapidly degraded at pH 1.2 (0.2 M Clark-Lubs buffer). At pH 7.4 (0.1 M phosphate buffer), CA was stable for up to 24 h and KA for up to 6 h. In human plasma, CA and KA can be considered stable for 24 h and 12 h at 37 °C, respectively. Caco-2 cells were considered viable when incubated with CA or KA in the range of 3.9–250 μM for 24 h. CA and KA exhibited moderate apparent permeability (Papp) of 4.67 (±0.08) × 10−6 cm/s and 4.66 (±0.04) × 10−6 cm/s, respectively. Simultaneous incubation with verapamil showed that P-glycoprotein does not play a relevant role on CA and KA oral absorption, with Papp of 4.48 (±0.26) × 10−6 cm/s and 5.37 (±0.72) × 10−6 cm/s observed for CA and KA, respectively.
The oral absorption of both CA and KA is driven by mainly passive permeability, is not limited by p-glycoprotein, but enteric-coated dosage forms should be used to avoid chemical instability in the gastric pH.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
New compounds with antituberculosis activity and their combination with classic drugs have been evaluated to determine possible interactions and antagonism. The aim of this study was to evaluate the ...in vitro activity of Casiopeínas® copper-based compounds (CasIIIia, CasIIIEa, and CasIIgly) alone and combined with isoniazid (INH), rifampicin, or ethambutol (EMB) against resistant and susceptible Mycobacterium tuberculosis. Seventeen clinical M. tuberculosis isolates (5 multi-drug resistant and 2 resistant to INH and/or EMB) were subjected to determination of the minimal inhibitory concentration (MIC) by the resazurin microtiter assay and combination assessment by the resazurin drug combination microtiter assay. The Casiopeínas® alone showed a remarkable effect against resistant isolates with MIC values from 0.78 to 12.50 μg/ml. Furthermore, a synergistic effect mainly with EMB is shown for both resistant and susceptible clinical isolates. Casiopeínas® are promising candidates for future investigation into the development of antituberculosis drugs, being one of the first examples of essential metal-based drugs used in this field.
INTRODUCTION: Resistance to first-line anti-tuberculosis drugs is a major concern in the treatment of the disease. New strategies, such as the use of efflux pump inhibitors (EPIs), are being ...investigated to improve the outcome of the treatment. Verapamil (VP), one such inhibitor,
was shown to inhibit several efflux pump (EP) Mycobacterium tuberculosis proteins and demonstrate synergic activity with anti-TB drugs.OBJECTIVE: To evaluate the combinatory effect of isoniazid (INH) and VP in M. tuberculosis.METHODS: Minimal inhibitory
concentrations and combinatory effects of INH+VP were determined using respectively resazurin microtitre assay plate (REMA) and resazurin drugs combination microtitre assay (REDCA). From the results, we selected three bacilli with different susceptibility profiles and assessed their expression
of 10 EP genes through quantitative reverse transcription polymerase chain reaction after exposure to INH, VP and INH + VP for 48 h.RESULTS: A significant reduction of INH MIC was observed in INH-susceptible isolates upon combination with VP. In brief, gene expression assays revealed
expression patterns that could be correlated with each resistance profile, presence or absence of gene mutations and combinatory effect with VP.CONCLUSION: Combining VP with INH showed important results in drug-susceptible strains, and clinical trials on combined VP + anti-TB drugs
should be discussed.
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•New furoxan compounds lead to undetectable M. tuberculosis in a mouse model of infection.•High activity against MDR and XDR-TB.•Early-bactericidal effect.•No mutagenic results were ...detected by AMES.•No damages in histological tissues.
The most recent survey conducted by the World Health Organization described Tuberculosis (TB) as one of the top 10 causes of death and the leading cause of death from a single infectious agent. The increasing number of TB-resistant cases has contributed to this scenario. In light of this, new strategies to control and treat the disease are necessary. Our research group has previously described furoxan derivatives as promising scaffolds to be explored as new antitubercular drugs. Results: Two of these furoxan derivatives, (14b) and (14c), demonstrated a high selectivity against Mycobacterium tuberculosis. The compounds (14b) and (14c) were also active against a latent M. tuberculosis strain, with MIC90 values of 6.67 μM and 9.84 μM, respectively; they were also active against monoresistant strains (MIC90 values ranging from 0.61 to 20.42 μM) and clinical MDR strains (MIC90 values ranging from 3.09 to 42.95 μM). Time-kill experiments with compound (14c) showed early bactericidal effects that were superior to those of the first- and second-line anti-tuberculosis drugs currently used in therapy. The safety of compounds (14b) and (14c) was demonstrated by the Ames test because these molecules were not mutagenic under the tested conditions. Finally, we confirmed the safety, and high efficacy of compounds (14b) and (14c), which reduced M. tuberculosis to undetectable levels in a mouse aerosol model of infection. Conclusion: Altogether, we have identified two advanced lead compounds, (14b) and (14c), as novel promising candidates for the treatment of TB infection.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A copper(II) complex-loaded castor oil-based nanostructured lipid carrier was evaluated to enhance the poor water solubility of antimicrobial compounds, improving their biological properties and ...antimicrobial activity against Mycobacterium tuberculosis. Nanostructured lipid carriers
were composed of the castor oil, polyoxyethylene 40 stearate and caprylic/capric triglyceride, poloxamer 407, cetyltrimethylammonium bromide and three different copper(II) complexes. The systems were ultrasonicated at an amplitude of 8% for 20 min and an ice bath was used throughout the procedure.
The blank nanostructured lipid carrier (F5) and nanostructured lipid carriers loaded with copper(II) complex 1, 2 and 3 (F5.1, F5.2 and F5.3, respectively) for 45 days presented values of mean diameter, poly dispersity index and zeta potential ranging from 186 to 199 nm, 0.14 to 0.2 and 24
to 30 mV, respectively. Atomic force microscopy indicated that the nanostructured lipid carriers were distributed at the nanoscale, corroborating the mean diameter data. Differential scanning calorimetry determined the melting points of the constituents of the nanostructured lipid carriers.
The antimicrobial activity of copper(II) complexloaded F5 against M. tuberculosis H37Rv showed better anti-tuberculosis activity than the free complexes. In vivo biological assays of complex-loaded F5 demonstrated reduced toxicity. Our results suggest that nanostructured
lipid carriers could be a potential nanotechnological strategy to optimise tuberculosis treatment.
SETTING: Department of Clinical Analysis and Biomedicine, State University of Maringa, Maringa, PR, Brazil.OBJECTIVE: To evaluate the performance of the resazurin microtiter assay (REMA) plate at pH ...5.5 in detecting Mycobacterium tuberculosis susceptibility to pyrazinamide
(PZA).DESIGN: The minimal inhibitory concentration (MIC) of PZA in M. tuberculosis H37Rv and M. bovis AN5 reference strains and in 34 clinical M. tuberculosis isolates (26 PZA-susceptible and eight PZA-resistant) was determined using REMA at pH 5.5 and compared
to REMA at pH 6.0.RESULTS: REMA at pH 5.5 was helpful in discriminating PZA-susceptible from resistant M. tuberculosis isolates when 50 μg/ml PZA was considered as the cut-off for PZA susceptibility. Furthermore, it provided results in 8 days. However, two PZA-resistant
isolates failed to grow at pH 5.5.CONCLUSION: As the REMA method is rapid, inexpensive, easy to perform and read, it would be of great usefulness in low-income countries for detecting PZA-resistant M. tuberculosis. REMA at pH 5.6-5.9 should be evaluated on an extended panel
of clinical M. tuberculosis isolates with a greater range of MIC values in different laboratories for a better understanding of its utility in differentiating PZA-resistant from PZA-susceptible isolates.
Summary
Rhodococcus equi is a well‐recognized Gram‐positive intracellular facultative bacterium that is opportunistic in nature, which causes pyogranulomatous infections in humans and multiple host ...animals. The pathogenicity of the microorganism has been attributed to the presence of plasmid‐encoded virulence‐associated proteins (Vap). To date, three host‐associated virulence plasmid types of R. equi have been identified as follows: the circular pVAPA and pVAPB, related, respectively, to equine and porcine isolates, and a recently described linear pVAPN plasmid associated with bovine strains, although these three types are found in human isolates. Recent phylogenomic studies support the evidence that human R. equi infection is zoonotically acquired. Nevertheless, data regarding distribution and prevalence of the host‐adapted virulence plasmid types of R. equi isolated from meat animals are scarce or unnoticed. Here, the three host‐associated virulence plasmid types (pVAPA, pVAPB, and pVAPN) were investigated in 154 R. equi isolates recovered from lymph nodes of cattle with lymphadenitis (n = 31), faeces of cattle without enteric signs (n = 49), as well as different clinical specimens from human patients (n = 74). The analysis of virulence profile of 74 R. equi from humans revealed six (8.1%) isolates pVAPB (type 8), two (2.7%) pVAPN, and one (1.3%) pVAPB (type 11), all of which were from lung samples from people living with HIV/AIDS. From the lymph node samples of cattle, 41.9% (13 of 31) isolates revealed pVAPN type, whereas all isolates from faecal samples were negative for three host‐associated types. Here, recently described bovine‐associated pVAPN type was detected in R. equi isolates recovered from the lungs of people living with HIV/AIDS and lymph nodes from slaughtered cattle intended for human consumption; a finding that represents a public health concern, mainly in countries where undercooked or raw meat are traditionally consumed.
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BFBNIB, DOBA, FZAB, GIS, IJS, IZUM, KILJ, NLZOH, NUK, OILJ, PILJ, PNG, SAZU, SBCE, SBMB, UILJ, UKNU, UL, UM, UPUK
The objective of this article is to provide evidence-based recommendations for the management of patients with herpes zoster (HZ) that take into account clinical efficacy, adverse effects, impact on ...quality of life, and costs of treatment. Systematic literature reviews, published randomized clinical trials, existing guidelines, and the authors' clinical and research experience relevant to the management of patients with HZ were reviewed at a consensus meeting. The results of controlled trials and the clinical experience of the authors support the use of acyclovir, brivudin (where available), famciclovir, and valacyclovir as first-line antiviral therapy for the treatment of patients with HZ. Specific recommendations for the use of these medications are provided. In addition, suggestions are made for treatments that, when used in combination with antiviral therapy, may further reduce pain and other complications of HZ.
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