Antifungal Activity, Mode of Action, Docking Prediction and Anti-biofilm Effects of (+)-ß-pinene Enantiomers against Candida spp.

AIMS: The objective of this study was to investigate the effectiveness of (+)-ß-pinene inhibition on Candida spp. growth, aiming at elucidation of the mechanism of action; to determine fungal cell enzyme binding activity (through molecular docking simulations) and its effects on biofilm reduction. METHODS: Candida strains (n=25) from referenced and clinical origins, either susceptible or resistant to standard clinical antifungals, were tested for determination of Minimum Inhibitory Concentration (MIC); Minimum Fungicidal Concentration (MFC); and microbial death curves upon treatment with (+)-ß-pinene; the effects of (+)-ß-pinene on the cell wall (sorbitol assay), membrane ergosterol binding, and effects on biofilm were evaluated by microdilution techniques. We also evaluated the interactions between (+)-ß-pinene and cell wall and membrane enzymes of interest. RESULTS: The MIC values of (+)-ß-pinene ranged from <56.25 to 1800 µmol/L. The MIC of (+)-ß-pinene did not increase when ergosterol was added to the medium, however it did increase in the presence of sorbitol, leading to a doubled MIC for C. tropicalis and C. krusei. The results of the molecular docking simulations indicated better interaction with delta-14-sterol reductase (-51 kcal/mol). (+)-ß-pinene presents anti-biofilm activity against multiples species of Candida. CONCLUSION: (+)-ß-pinene has antifungal activity and most likely acts through interference with the cell wall; through molecular interaction with Delta-14-sterol reductase and, to a lesser extent, with the 1,3-ß- glucan synthase. This molecule was also found to effectively reduce Candida biofilm adhesion.

Zornioside, a dihydrochalcone C-glycoside, and other compounds from Zornia brasiliensis

ABSTRACT The secondary metabolites of the aerial parts of Zornia brasiliensis Vogel, Fabaceae, and the biological activity of one of these secondary metabolites were characterized in this study. A phytochemical investigation was performed using chromatographic techniques including analytical and preparative reverse-phase HPLC column sequences, which resulted in the isolation of fourteen compounds: one previously undescribed C-glycosylated dihydrochalcone (zornioside), one cyclitol (D-pinitol), one glycosylated megastigmane (roseoside) and eleven phenolic compounds: 7-methoxyflavanone, 7,4'-dimethoxyisoflavone, medicarpin, 2'-4'-dihydroxychalcone, onionin, isoorientin-3'-O-methyl ether, isovitexin, glycosylated (Z)-O-coumaric acid, glycosylated (E)-O-coumaric acid, dihydromelilotoside, and isoorientin. The structures of the isolated compounds were determined based on 1D and 2D-NMR, HRESIMS, IR and CD spectroscopic analyses. The cytotoxic activity of zornoside was assessed against tumor cell lines (MCF-7, HCC1954, T-47D, 4T1, HL60), and a non-tumor cell line (RAW264.7) using MTT assay. The compound zornioside was selectively cytotoxic for HL60 leukemia cells (IC50: 37.26 µM).

Synthesis and Chemometrics of Thymol and Carvacrol Derivatives as Larvicides against Aedes aegypti.

BACKGROUND: Thymol and carvacrol have previously demonstrated larvicidal activity against Aedes aegypti (Diptera: Culicidae). In view of this fact, it was of our interest to obtain synthetic derivatives and evaluate their larvicidal activity on Ae. aegypti larvae. METHODS: Structural modifications were performed on thymol and carvacrol in an effort to understand the functional groups necessary for modulating their activities and to lead possibly to more effective larvae control agents. The derivatives were further subjected to SAR and computational studies (molecular modeling and chemometric tools (CPCA and PCA)) to extract structural information regarding their larvicidal properties. Field collected and Rockefeller populations of Ae. aegypti were used. RESULTS: Carvacrol and thymol exhibited LC50 of 51 and 58ppm for field collected larvae, respectively. Carvacrol derivatives exhibited LC50 ranging from 39 to 169ppm, while thymol derivatives exhibited LC50 ranging from 18 to 465ppm. Substitution of the acidic proton of carvacrol by esters, ethers, and acetic acid resulted in either maintenance or reduction of potency. CONCLUSION: Thymol derivatives were, to a certain extent, more efficient larvicides against Ae. aegypti than carvacrol derivatives, particularly to Rockefeller larvae. The chemometrics tools applied in this study showed that the independent variables indicate a mixed profile. Nevertheless, hydrophobic interactions increased the larvicidal activity.

Polyphenols rich Passiflora leschenaultii leaves modulating Farnesoid X Receptor and Pregnane X Receptor against paracetamol-induced hepatotoxicity in rats.

The hepatoprotective effect of P. leschenaultii. (DC) leaves was investigated in rats under paracetamol induced oxidative stress. Leaf acetone extract (200 and 400mg/kg) were administered daily via gavage for 14days before paracetamol (2000mg/kg, p.o.) treatment. After the experiment, the levels of serum biochemical parameters and enzymatic antioxidant levels were determined. Furthermore, liver tissues were analyzed histopathologically. Additionally, the molecular docking studies of the identified compounds against PXR and FXR proteins were also performed. The assessment revealed that the acetone extract significantly reduced the elevated levels of SGPT, SGOT and ALP in serum. Moreover, the enzymatic antioxidants such as SOD, CAT and LPO were also retained normally by the plant extract. From histopathological analysis, it was clearly evident that the cellular architecture of plant extract treated rat liver tissues were not affected by the paracetamol induction at the higher dose. The results of docking studies also revealed that the identified compounds showed steric interactions (between nonpolar atoms) with amino acid groups. Collectively, the present study suggests that P. leschenaultii leaves extract protects the liver from paracetamol induced hepatic damage.

Current pharmaceutical design of antituberculosis drugs: future perspectives.

The increasing resistance of Mycobacterium tuberculosis to the existing drugs has alarmed the worldwide scientific community. In an attempt to overcome this problem computer-aided drug design has provide an extraordinary support to the different strategies in drug discovery. There are around 250 biological receptors like enzymes that can be used in principle, for the design of antituberculosis compounds that act by a specific mechanism of action. Also, there more than 5000 compound available in the literature, and that constitute important information in order to search new molecular patterns for the design of new antituberculosis agents. The purpose of this paper is to explored the current state of drug discovery of antituberculosis agents and how the different strategies supported by computer-aided drug design methods has influenced in a determinant way in the design of new molecular entities that can result the future antituberculosis drugs.

Designing novel antitrypanosomal agents from a mixed graph-theoretical substructural approach.

Chagas disease is nowadays the most serious parasitic health problem. This disease is caused by Trypanosoma cruzi. The great number of deaths and the insufficient effectiveness of drugs against this parasite have alarmed the scientific community worldwide. In an attempt to overcome this problem, a model for the design and prediction of new antitrypanosomal agents was obtained. This used a mixed approach, containing simple descriptors based on fragments and topological substructural molecular design descriptors. A data set was made up of 188 compounds, 99 of them characterized an antitrypanosomal activity and 88 compounds that belong to other pharmaceutical categories. The model showed sensitivity, specificity and accuracy values above 85%. Quantitative fragmental contributions were also calculated. Then, and to confirm the quality of the model, 15 structures of molecules tested as antitrypanosomal compounds (that we did not include in this study) were predicted, taking into account the information on the abovementioned calculated fragmental contributions. The model showed an accuracy of 100% which means that the "in silico" methodology developed by our team is promising for the rational design of new antitrypanosomal drugs.

Design of novel antituberculosis compounds using graph-theoretical and substructural approaches.

The increasing resistance of Mycobacterium tuberculosis to the existing drugs has alarmed the worldwide scientific community. In an attempt to overcome this problem, two models for the design and prediction of new antituberculosis agents were obtained. The first used a mixed approach, containing descriptors based on fragments and the topological substructural molecular design approach (TOPS-MODE) descriptors. The other model used a combination of two-dimensional (2D) and three-dimensional (3D) descriptors. A data set of 167 compounds with great structural variability, 72 of them antituberculosis agents and 95 compounds belonging to other pharmaceutical categories, was analyzed. The first model showed sensitivity, specificity, and accuracy values above 80% and the second one showed values higher than 75% for these statistical indices. Subsequently, 12 structures of imidazoles not included in this study were designed, taking into account the two models. In both cases accuracy was 100%, showing that the methodology in silico developed by us is promising for the rational design of antituberculosis drugs.