Liposomal nanoformulations with trans-caryophyllene and caryophyllene oxide: do they have an inhibitory action on the efflux pumps NorA, Tet(K), MsrA, and MepA?

This study aimed to evaluate the antibacterial and inhibitory action of NorA, Tet(K), MsrA and MepA efflux pumps in S. aureus strains using the sesquiterpenes named trans-caryophyllene and caryophyllene oxide, both isolated and encapsulated in liposomes. The antibacterial and inhibitory action of these efflux pumps was evaluated through the serial microdilution test in 96-well microplates. Each sesquiterpene and liposome/sesquiterpene was combined with antibiotics and ethidium bromide (EtBr). The antibiotics named norfloxacin, tetracycline and erythromycin were used. The 1199 B, IS-58, RN4220 and K2068 S. aureus strains carrying NorA, Tet(K), MsrA and MepA, respectively, were tested. In the fluorescence measurement test, K2068 S. aureus was incubated with the sesquiterpenes and EtBr, and the fluorescence emission by EtBr was measured. The tested substances did not show direct antibacterial activity, with MIC >1024 µg/mL. Nonetheless, the isolated trans-caryophyllene and caryophyllene oxide reduced the MIC of antibiotics and EtBr, indicating inhibition of NorA, Tet(K) and MsrA. In the fluorescence test, these same sesquiterpenes increased fluorescence emission, indicating inhibition of MepA. Therefore, the sesquiterpenes named trans-caryophyllene and caryophyllene oxide did not show direct antibacterial action; however, in their isolated form, they showed possible inhibitory action on NorA, Tet(K), MsrA and MepA efflux pumps. They may also act in antibiotic potentiation. Further studies are needed to identify the mechanisms involved in antibiotic potentiation and efflux pump inhibitory action.

Effect of the Aqueous Extract of Chrysobalanus icaco Leaves on Maternal Reproductive Outcomes and Fetal Development in Wistar Rats.

Toxicological studies on medicinal plants are essential to ensure their safety and effectiveness in treating various diseases. Despite the species Chrysobalanus icaco L. being popularly used in the treatment of several diseases due to the pharmacological properties of its bioactive compounds, there are few studies in the literature regarding its toxicity regarding reproduction. Therefore, the purpose of this study was to assess the potential embryotoxic and teratogenic effects of the aqueous extract of C. icaco leaves (AECi) on Wistar rats. Animals were given AECi at doses of 100, 200, and 400 mg/kg during the pre-implantation and organogenesis periods. Data were analyzed using ANOVA followed by Tukey's test and Kruskal-Wallis. Pregnant rats treated during the pre-implantation period showed no signs of reproductive toxicity. Rats that received AECi at 100, 200, and 400 mg/kg during organogenesis did not exhibit any signs of maternal systemic toxicity or significant differences in gestational and embryotoxic parameters. Some skeletal changes were observed in the treated groups. Therefore, it can be suggested that AECi at doses of 100, 200, and 400 mg/kg is safe for treated animals and does not induce reproductive toxicity under the experimental conditions applied, but it also caused low systemic toxicity.

The 1,8-naphthyridines sulfonamides are NorA efflux pump inhibitors.

OBJECTIVE: Efflux pumps are transmembrane proteins associated with bacterial resistance mechanisms. Bacteria use these proteins to actively transport antibiotics to the extracellular medium, preventing the pharmacological action of these drugs. This study aimed to evaluate in vitro the antibacterial activity of 1,8-naphthyridines sulfonamides, as well as their ability to inhibit efflux systems of Staphylococcus aureus strains expressing different levels of the NorA efflux pump. METHODS: The broth microdilution test was performed to assess antibacterial activity. Efflux pump inhibition was evaluated in silico by molecular docking and in vitro by fluorometric tests, and the minimum inhibitory concentration (MIC) was determined. The MIC was determined in the association between 1,8-naphthyridine and norfloxacin or ethidium bromide. RESULTS: The 1,8-naphthyridines did not show direct antibacterial activity. However, they effectively reduced the MIC of multidrug-resistant bacteria by associating with norfloxacin and ethidium bromide, in addition to increasing the fluorescence emission. In silico analysis addressing the binding between NorA and 1,8-naphthyridines suggests that hydrogen bonds and hydrophilic interactions represent the interactions with the most favourable binding energy, corroborating the experimental data. CONCLUSION: Our data suggest that 1,8-naphthyridines sulfonamides inhibit bacterial resistance through molecular mechanisms associated with inhibition of the NorA efflux pump in S. aureus strains.

Do 1,8-naphthyridine sulfonamides possess an inhibitory action against Tet(K) and MsrA efflux pumps in multiresistant Staphylococcus aureus strains?

Naphthyridines represent a class of heterocyclic compounds formed by two condensed aromatic rings. This study aimed to evaluate the antibacterial activity and in vitro inhibition of efflux resistance mechanisms of a series of 1,8-naphthyridine sulfonamides against strains carrying Tet(K) and MsrA efflux pumps. The efflux pump inhibitory capacity was evaluated by analyzing synergistic effects between 1,8-naphthyridine sulfonamides and standard antibiotics, as well as ethidium bromide. The following 1,8-naphthyridines were used: 4-methyl-N-(5-chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Naph 1); 2,5-Dichloro-N-(5-chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Naph 2); 2,3,4-trifluoro-N-(5-chloro-1,8-naphthyridin-2-yl)benzenesulfonamide (Naph 7); 3-trifluoromethyl-N-(5-chloro-1,8-naphthyridin-2-yl)-benzenesulfonamide (Naph 9). The 1,8-naphthyridine sulfonamide derivatives possessed a potential Tet(K) and MsrA efflux pump inhibitory action.

Anacardium Plants: Chemical,Nutritional Composition and Biotechnological Applications.

Anacardium plants are native to the American tropical regions, and Anacardium occidentale L. (cashew tree) is the most recognized species of the genus. These species contain rich secondary metabolites in their leaf and shoot powder, fruits and other parts that have shown diverse applications. This review describes the habitat and cultivation of Anacardium species, phytochemical and nutritional composition, and their industrial food applications. Besides, we also discuss the secondary metabolites present in Anacardium plants which display great antioxidant and antimicrobial effects. These make the use of Anacardium species in the food industry an interesting approach to the development of green foods.

Synthesis, in vitro and in vivo biological evaluation, COX-1/2 inhibition and molecular docking study of indole-N-acylhydrazone derivatives.

The objective of this work was to obtain and evaluate anti-inflammatory in vitro, in vivo and in silico potential of novel indole-N-acylhydrazone derivatives. In total, 10 new compounds (3a-j) were synthesized in satisfactory yields, through a condensation reaction in a single synthesis step. In the lymphoproliferation assay, using mice splenocytes, 3a and 3b showed inhibition of lymphocyte proliferation of 62.7% (±3.5) and 50.7% (±2), respectively, while dexamethasone presented an inhibition of 74.6% (±2.4). Moreover, compound 3b induced higher Th2 cytokines production in mice splenocytes cultures. The results for COX inhibition assays showed that compound 3b is a selective COX-2 inhibitor, but with less potency when compared to celecoxib, and compound 3a not presented selectivity towards COX-2. The molecular docking results suggest compounds 3a and 3b interact with the active site of COX-2 in similar conformations, but not with the active site of COX-1, and this may be the main reason to the COX-2 selectivity of compound 3b. In vivo carrageenan-induced paw edema assays were adopted for the confirmation of the anti-inflammatory activity. Compound 3b showed better results in suppressing edema at all tested concentrations and was able to induce an edema inhibition of 100% after 5 h of carrageenan injection at the 30 mg kg-1 dosage, corroborating with the COX inhibition and lymphoproliferation results. I addition to our experimental results, in silico analysis suggest that compounds 3a and 3b present a well-balanced profile between pharmacodynamics and pharmacokinetics. Thus, our preliminary results revealed the potentiality of a new COX-2 selective derivative in the modulation of the inflammatory process.

New thiazolidinedione LPSF/GQ-2 inhibits NFκB and MAPK activation in LPS-induced acute lung inflammation.

Acute lung injury (ALI) and acute respiratory distress syndrome (ARDS) are responsible for high mortality rates in critical patients. Despite >50 years of intensive research, there is no pharmacologically effective treatment to treat ALI. PPARs agonists, chemically named thiazolidinediones (TZDs) have emerged as potential drugs for the treatment of ALI and ARDS due to their anti-inflammatory efficacy. The present study aims to evaluate the potential anti-inflammatory effects of new TZDs derivatives, LPSF/GQ-2 and LPSF/RA-4, on ALI induced by LPS. BALB/c mice were divided into five groups: 1) Control; 2) LPS intranasal 25 µg; 3) LPSF/GQ-2 30 mg/kg + LPS; 4) LPSF/RA-4 20 mg/kg + LPS; and 5) DEXA 1 mg/Kg + LPS. BALF analyses revealed that LPSF/GQ-2 and LPSF/RA-4 reduced NO levels in BALF and inflammatory cell infiltration induced by LPS. MPO levels were also reduced by the LPSF/GQ-2 and LPSF/RA-4 pre-treatments. In contrast, histopathological analyses showed better tissue protection with LPSF/GQ-2 than DEXA and LPSF/RA-4 groups. Similarly, LPSF/GQ-2 reduced inflammatory markers (IL-1, iNOS, TNFα, IL-1ß, IL-6) better than LPSF/RA-4. The LPSF/GQ-2 anti-inflammatory action could be attributed to the inhibition of NFκB, ERK, p38, and PARP pathways. In contrast, LPSF/RA-4 had no effect on the expression of p38, JNK, NFκB. The present study indicates that LPSF/GQ-2 presents a potential therapeutic role as an anti-inflammatory drug for ALI.

Evaluation of acute toxicity, genotoxicity and inhibitory effect on acute inflammation of an ethanol extract of Morus alba L. (Moraceae) in mice.

ETHNOPHARMACOLOGICAL RELEVANCE: Morus alba L. (white mulberry) is used in traditional medicine worldwide, including Brazil. The leaves of this plant are used to treat inflammatory disorders. Universal interest in this plant necessitates studies on the toxicological safety and scientific substantiation of the medicinal properties of M. alba. In previous work, we investigated the acute toxicity of orally administered M. alba ethanol extract in mice. AIM OF THE STUDY: This work was designed to investigate the ethanol extract obtained from M. alba leaves for acute toxicity when intraperitoneally administered, in vivo genotoxicity, and potential to reduce acute inflammation. In order to further investigate the constituents of the extract, we also obtained the high-performance liquid chromatography (HPLC) fingerprint of the extract. MATERIALS AND METHODS: Phytochemical analysis by thin layer chromatography (TLC) was performed and the results were used to obtain the HPLC fingerprint. Acute toxicity of 300 and 2000mg/kg b.w. i.p. doses administered to mice for 14 days was evaluated. Genotoxicity was evaluated by counting the number of micronucleated polychromatic erythrocytes in the blood of mice that either received or did not receive the extract at 75, 150 and 300mg/kg b.w. per os. The anti-inflammatory effect of the same doses administered per os was investigated using the carrageenan air pouch model. RESULTS: The TLC analysis of the extract revealed the presence of a remarkable amount of flavonoids and cinnamic acids. The HPLC fingerprint showed the presence of one major peak corresponding to chlorogenic acid and two smaller peaks corresponding to flavonoids. In the toxicity assays, there were no deaths or deviations in behavior of treated mice as compared to the control at any dose. However, biochemical, hematological, and histological analyses showed that intraperitoneal injection caused several forms of damage to the mice, which were not observed in case of oral administration, studied in our previous work. Oral administration of the extract did not result in genotoxicity and considerably reduced (58.6-65.6% inhibition) leukocyte migration in all doses evaluated, in comparison with the negative control. CONCLUSIONS: The ethanol extract from M. alba leaves administered intraperitoneally possesses a greater degree of toxicity in mice when compared to per os administration. The extract was not genotoxic when ingested by mice and exhibited a highly inhibitory effect against acute inflammation, which is probably linked to the presence of chlorogenic acid and flavonoids in the composition. This work contributes to the determination of safety of the medicinal use of M. alba leaves.

Repeated-doses and reproductive toxicity studies of the monoterpene 1,8-cineole (eucalyptol) in Wistar rats.

1,8-cineole (eucalyptol) is widely used as an excipient in the pharmaceutical industry and as a food flavoring agent, thus providing significant potential for human exposure to the compound. We investigated the preclinical toxicity and reproductive toxicity of 1,8-cineole (CIN). In the repeated-doses toxicity study for 50 days, CIN (100, 500 or 1000 mg/kg) did not produce any signs of toxicity or deaths, but affected body weight gain during the first week of treatment. The hematological and biochemical profiles did not show significant differences except for increase in the MCV, platelet and urea levels or reduction in MCHC, MPV and alkaline phosphatase. Histopathological analysis showed weak changes in the lungs, liver, kidneys and uterus. In the reproductive toxicity, CIN (250, 500 or 1000 mg/kg) produced a reduction in body weight in pregnant rats treated during the pre-implantation or organogenesis periods. The highest doses induced a reduction in the mass of fetuses (pre-implantation) and dead fetuses (both periods) of pregnant rats. The results indicate that the treatment by repeated-doses showed occasional alterations in rats of both sexes. However, provide evidence that possibly 1,8-cineole presents maternal and fetal toxicity. This requires more detailed investigation to better characterize the toxic effects of this compound.

Synthesis and anti-inflammatory activity of new arylidene-thiazolidine-2,4-diones as PPARgamma ligands.

Eight new 5-arylidene-3-benzyl-thiazolidine-2,4-diones with halide groups on their benzyl rings were synthesized and assayed in vivo to investigate their anti-inflammatory activities. These compounds showed considerable biological efficacy when compared to rosiglitazone, a potent and well-known agonist of PPARgamma, which was used as a reference drug. This suggests that the substituted 5-arylidene and 3-benzylidene groups play important roles in the anti-inflammatory properties of this class of compounds. Docking studies with these compounds indicated that they exhibit specific interactions with key residues located in the site of the PPARgamma structure, which corroborates the hypothesis that these molecules are potential ligands of PPARgamma. In addition, competition binding assays showed that four of these compounds bound directly to the ligand-binding domain of PPARgamma, with reduced affinity when compared to rosiglitazone. An important trend was observed between the docking scores and the anti-inflammatory activities of this set of molecules. The analysis of the docking results, which takes into account the hydrophilic and hydrophobic interactions between the ligands and the target, explained why the 3-(2-bromo-benzyl)-5-(4-methanesulfonyl-benzylidene)-thiazolidine-2,4-dione compound had the best activity and the best docking score. Almost all of the stronger hydrophilic interactions occurred between the substituted 5-arylidene group of this compound and the residues of the binding site.