Isolation and comparative genotoxicity screening of trichokonins VI and VIII on CHO-K1 cells.

Peptaibols are fungal peptides that exhibit efficacy against pathogen microorganisms. Trichokonin VI (TK-VI) and trichokonin VIII (TK-VIII) are known peptaibols isolated from the endolichenic fungi Hypocrea sp. Previous investigations reported that trichokonin VI presents antiproliferative effects on tumor cells. This study is pioneering in elucidating the genotoxic effects of TK-VI and TK-VIII, contributing to the thorough assessment of their safety as potential therapeutic agents. The present investigation aimed to evaluate the genotoxicity of TK-VI and TK-VIII on CHO-K1 cells. Cytotoxicity was evaluated using the XTT assay and clonogenic survival assays, followed by evaluation of DNA damage using the comet assay and micronucleus test conducted in vitro. The XTT assay results indicated IC50 values of 10.30 µM and 9.89 µM for TK-VI and TK-VIII, respectively. The clonogenic survival assay indicated that concentrations of 10 µM or higher completely inhibited the cell colony formation. In the comet assay, both TK-VI and TK-VIII increased the DNA damage score and the frequency of comet nuclei in all tested concentrations. In the micronucleus assay, TK-VI and TK-VIII at 10 µM increased the frequency of MN in CHO-K1 cells. Both TK-VI and TK-VIII exhibited genotoxic effects. Our findings underscore the importance of considering the genotoxicological safety of peptaibols, particularly when assessing their potential for other biological activities.

Production of new ent-hardwickiic acid derivatives by microbial transformation and their antifungal activity.

Ent-hardwickiic acid is the major compound of Copaifera pubiflora Benth oleoresin traditionally used in Brazilian folk medicine as an antimicrobial agent. Microbial transformation of ent-hardwickiic by Cunninghamella elegans ATCC 10028b resulted in two and five antifungal derivatives (four new ones) produced in the Czapek modified and Koch's K1 media, respectively. The derivatives were isolated and their structures were determined by spectral analysis, namely 1D/2D NMR and HR-ESIMS. All compounds were tested for cytotoxic and antifungal activities and they were not cytotoxic to the tested cell lines, but all derivatives showed fungicidal activity against Candida glabrata and Candida krusei, which have emerged as resistant to fluconazole. One of the yet unreported biotransformation products displayed the strongest activity with minimum fungicidal concentration values smaller than the other compounds, including fluconazole.

Polyketide- and Terpenoid-Derived Metabolites Produced by a Marine-Derived Fungus, Peroneutypa sp.

Bioassay-guided investigation of the EtOAc-soluble extract of a culture of the marine-derived fungus Peroneutypa sp. M16 led to the isolation of seven new polyketide- and terpenoid-derived metabolites (1, 2, 4-8), along with known polyketides (3, 9-13). Structures of compounds 1, 2, and 4-8 were established by analysis of spectroscopic data. Absolute configurations of compounds 1, 2, 4, 6, 7, and 8 were determined by the comparison of experimental ECD spectra with calculated CD data. Compound 5 exhibited moderate antiplasmodial activity against both chloroquine-sensitive and -resistant strains of Plasmodium falciparum.

Intrinsically Disordered Protein Micelles as Vehicles for Convection-Enhanced Drug Delivery to Glioblastoma Multiforme.

Lipid and micelle-based nanocarriers have been explored for anticancer drug delivery to improve accumulation and uptake in tumor tissue. As an experimental opportunity in this area, our lab has developed a protein-based micelle nanocarrier consisting of a hydrophilic intrinsically disordered protein (IDP) domain bound to a hydrophobic tail, termed IDP-2Yx2A. This construct can be used to encapsulate hydrophobic chemotherapeutics that would otherwise be too insoluble in water to be administered. In this study, we evaluate the in vivo efficacy of IDP-2Yx2A by delivering a highly potent but water-insoluble cancer drug, SN38, into glioblastoma multiforme (GBM) tumors via convection-enhanced delivery (CED). The protein carriers alone are shown to elicit minimal toxicity effects in mice; furthermore, they can encapsulate and deliver concentrations of SN38 that would otherwise be lethal without the carriers. CED administration of these drug-loaded micelles into mice bearing U251-MG GBM xenografts resulted in slowed tumor growth and significant increases in median survival times compared to nonencapsulated SN38 and PBS controls.

Contrasting sewage, emerging and persistent organic pollutants in sediment cores from the River Thames estuary, London, England, UK.

Sedimentary organic pollution in the urban reaches of the Thames estuary is changing from fossil fuel hydrocarbons to emerging synthetic chemicals. De-industrialisation of London was assessed in three cores from Chiswick (Ait/Eyot) mud island using pharmaceuticals, faecal sterols, hydrocarbons (TPH, PAH), Black Carbon (BC) and organotins (TBT). These ranked in the order; BC 7590-30219 mg/kg, mean 16,000 mg/kg > TPH 770-4301, mean 1316 mg/kg > Σ16PAH 6.93-107.64, mean 36.46 mg/kg > coprostanol 0.0091-0.42 mg/kg, mean of 0.146 mg/kg > pharmaceuticals 2.4-84.8 µg/kg, mean 25 µg/kg. Hydrocarbons co-varied down-profile revealing rise (1940s), peak (1950s -1960s) and fall (1980s) and an overall 3 to 25-fold decrease. In contrast, antibiotics, anti-inflammatory (ibuprofen, paracetamol) and hormone (17ß-estradiol) increased 3 to 50-fold toward surface paralleling increasing use (1970s-2018). The anti-epileptics, carbamazepine and epoxcarbamazepine showed appreciable down-core mobility. Faecal sterols confirmed non-systematic incorporation of treated sewage. Comparison to UK sediment quality guidelines indicate exceedance of AL2 for PAH whereas TBT was below AL1.

Production of More Potent Anti-Candida Labdane Diterpenes by Biotransformation Using Cunninghamella elegans.

Candida species are responsible for causing invasive candidiasis with high mortality rate and their resistance to available antifungal drugs is a major clinical challenge. Biotransformation process of the labdane diterpene ent-labd-8(17)-en-15,18-dioic acid (1) carried out with Cunninghamella elegans afforded five new derivatives (compounds 2-6). Unusual regioselective hydroxylation of the methyl group at the C-20 position of labdane-type diterpene was achieved and all compounds were subjected to cytotoxicity and antifungal evaluations. Compound 1 and its derivatives were not cytotoxic to normal (MCF-10A) and tumor (MCF-7) cell lines. Compounds 2 and 3 exhibited fungistatic activity against all tested Candida strains at lower concentrations than fluconazole. Both compounds also showed the strongest fungicidal activity against C. albicans, which is the most prevalent fungal agent involved in candidemia.

Systemic expression of genes related to inflammation and lipid metabolism in patients with dyslipidemia, type 2 diabetes mellitus and chronic periodontitis.

Inflammatory diseases, as periodontal disease (PD), has been associated with disturbance of lipid and glycemic metabolisms, as demonstrated by the increasing of PD patients with type 2 diabetes mellitus (T2D) and/or dyslipidemia comorbidities. We aimed to investigate the expression of inflammation and lipid metabolism genes, and correlations among clinical and biochemical characteristics in normoglycemic or T2D patients with dyslipidemia and PD, in comparison with healthy individuals. Five groups of 30 individuals each (150 patients) were formed based upon T2D, dyslipidemic and periodontal status. Blood analyses of lipid and glycemic profiles were carried out, and the gene expression was assessed by RT-qPCR. The systemic expression of IL6, TNFA and LEP genes were significantly higher in T2D, dyslipidemia and PD patients, while the PECAM1 gene showed the opposite. Higher RETN levels were found in patients with T2D independently of their glycemic control status. There were positive correlations between: TNFA, LEP and RETN with worse periodontal parameters; IL6, TNFA, ADIPOR1, LEP and RETN with waist-to-hip ratio; glycemic parameters with RETN; total cholesterol and triglycerides with LEP expression. We conclude that pro-inflammatory cytokines were related with worse lipid, glycemic and periodontal parameters, reinforcing that a hyper-inflammatory status connects systemic and oral inflammatory diseases.

In vitro cytotoxicity and structure-activity relationship approaches of ent-kaurenoic acid derivatives against human breast carcinoma cell line.

In this study, ent-kaurenoic acid derivatives were obtained by microbial transformation methodologies and tested against breast cancer cell lines (MCF-7). A multivariate quantitative-structure activity relationship (QSAR) analysis was performed taking into account both microbial transformation derivatives and other analogues previously reported in literature to give some insight into the main features behind the cytotoxic activity displayed by kaurane-type diterpenes against MCF-7 cells. The partial least square regression (PLS) method was employed in the training set and the best PLS model was built with a factor describing 69.92% of variance and three descriptors (logP, εHOMO and εHOMO-1) selected by the Ordered Predictors Selection (OPS) algorithm. The QSAR model provided reasonable regression (Q2 = 0.64, R2 = 0.72, SEC = 0.29 and SEV = 0.33). The model was validated by leave-N-out cross-validation, y-randomization and external validation (R2pred = 0.89 and SEP = 0.27). The selected descriptors indicated that the activity was mainly related to electronic parameters (HOMO and HOMO-1 molecular orbital energies), as well as to logP. These findings suggest that higher activity values are directly related with both higher logP and frontier orbital energy values. The positive relationship between these orbitals and the activity suggests that the ent-kaurenoic acid analogues interaction with the target involves charge displacement, which is entirely consistent with the literature. Based on these findings, three compounds were proposed and one of them was synthesized and tested. The experimental result confirmed the activity predicted by the model.

Frequencies of CD39, IVS1-1, IVS1-6 and IVS1-110 mutations in beta-thalassemia carriers and their influence on hematimetric indices / Frequências de mutações CD39, IVS1-1, IVS1-6 e IVS1-110 em portadores de betatalassemia e suas influências nos valores hematimétricos

ABSTRACT Introduction: Beta-thalassemia is caused by a deficient synthesis of the ß-chain of hemoglobin, which leads to a chronic, microcytic and hypochromic anemia. More than 200 mutations have already been associated with this type of thalassemia, and their frequencies may vary according to the population. Objectives: The objectives of this study were to determine the frequencies of CD39, IVS1-1, IVS1-6 and IVS1-110 mutations in people with beta-thalassemia from the city of Franca, São Paulo, and to evaluate the influence of the genotypes on hematological alterations. Methods: Venous blood samples were collected from 25 volunteers previously diagnosed with beta-thalassemia. Complete blood counts (CBC) were performed, and the identification of the mutations was carried out using the polymerase chain reaction (PCR). Results: The CD39 mutation was found in 11 (44%) individuals, followed by IVS1-6 (9; 36%) and IVS1-110 (4; 16%). One patient (4%) did not present any of these mutations. IVS1-6 mutation was inversely correlated to red cell distribution width (RDW) (rs = -0.44; p = 0.034), and CD39 was correlated to lower mean corpuscular volume (MCV) (rs = -0.44; p = 0.034). Multivariable linear regression models showed that the CD39 mutation carriers have lower levels for hemoglobin (ß = -0.61; p = 0.044) and hematocrit (ß = -2.1; p = 0.018). Conclusion: The results showed a high frequency of the CD39 mutation in the city of Franca, and the correlations observed between the presence of CD39 mutation and the hematological alterations suggest a genotype influence on the phenotype of beta-thalassemia, which would contribute to the clinical variations of this hemoglobinopathy.

RESUMO Introdução: A betatalassemia é causada pela síntese deficiente da cadeia ß da hemoglobina, o que leva à ocorrência das anemias crônica, microcítica e hipocrômica. Mais de 200 mutações já foram associadas a esse tipo de talassemia, mesmo que diferentes populações apresentem frequências variadas para cada uma delas. Objetivos: Os objetivos deste estudo foram determinar as frequências das mutações CD39, IVS1-1, IVS1-6 e IVS1-110 em indivíduos betatalassêmicos da cidade de Franca, São Paulo, e avaliar a influência dos genótipos sobre alterações hematológicas. Métodos: Amostras de sangue venoso foram coletadas de 25 voluntários previamente diagnosticados com betatalassemia. Foram realizados hemogramas completos, e a identificação das mutações foi feita utilizando a técnica de reação em cadeia da polimerase (PCR). Resultados: A mutação CD39 foi encontrada em 44% dos indivíduos, seguida por IVS1-6 (36%) e IVS1-110 (16%). Um paciente (4%) não apresentou nenhuma das mutações. A mutação IVS1-6 correlacionou-se inversamente ao red cell distribution width (RDW) (rs = -0,44; p = 0,034), enquanto a presença da mutação CD39 mostrou-se correlacionada a menores valores de volume corpuscular médio (VCM) (rs = -0,44; p = 0,034). Modelos de regressão linear multivariados mostraram que os portadores da mutação CD39 possuem menores valores de hemoglobina (ß = -0,61; p = 0,044) e hematócrito (ß = -2,1; p = 0,018). Conclusão: Os resultados mostraram alta frequência da mutação CD39 na cidade de Franca, e as correlações observadas entre a presença da mutação CD39 e as alterações hematológicas sugerem influência do genótipo sobre o fenótipo da betatalassemia, o que poderia contribuir para as variações clínicas dessa hemoglobinopatia.

Condensation of Macrocyclic Polyketides Produced by Penicillium sp. DRF2 with Mercaptopyruvate Represents a New Fungal Detoxification Pathway.

Application of a refined procedure of experimental design and chemometric analysis to improve the production of curvularin-related polyketides by a marine-derived Penicillium sp. DRF2 resulted in the isolation and identification of cyclothiocurvularins 6-8 and cyclosulfoxicurvularins 10 and 11, novel curvularins condensed with a mercaptolactate residue. Two additional new curvularins, 3 and 4, are also reported. The structures of the sulfur-bearing curvularins were unambiguously established by analysis of spectroscopic data and by X-ray diffraction analysis. Analysis of stable isotope feeding experiments with [U-(13)C3(15)N]-l-cysteine confirmed the presence of the 2-hydroxy-3-mercaptopropanoic acid residue in 6-8 and the oxidized sulfoxide in 10 and 11. Cyclothiocurvularins A (6) and B (7) are formed by spontaneous reaction between 10,11-dehydrocurvularin (2) and mercaptopyruvate (12) obtained by transamination of cysteine. High ratios of [U-(13)C3(15)N]-l-cysteine incorporation into cyclothiocurvularin B (7), the isolation of two diastereomers of cyclothiocurvularins, the lack of cytotoxicity of cyclothiocurvularin B (7) and its methyl ester (8), and the spontaneous formation of cyclothiocurvularins from 10,11-dehydrocurvularin and mercaptopyruvate provide evidence that the formation of cyclothiocurvularins may well correspond to a 10,11-dehydrocurvularin detoxification process by Penicillium sp. DRF2.

Antifungal and Cytotoxic Assessment of Lapachol Derivatives Produced by Fungal Biotransformation.

In the screening for biological active compounds, the biotransformation processes catalyzed by filamentous fungi are useful because they can provide information about the possible appearance of toxic metabolites after oral administration and also generate new leads. In this paper, biotransformation of lapachol (1) by three fungal strains, Mucor circinelloides NRRL3631, Botrytis cinerea UCA992 and Botrytis cinerea 2100, has been investigated for the first time. Lapachol (1) was biotransformed into avicequinone-A (2) by M circinelloides, 3'-hydroxylapachol (3) by B. cinerea, and into dehydro-α-lapachone (4) by both fungi. All these compounds were evaluated for their cytotoxic activities. The metabolite 2 displayed non-selective cytotoxicity against tumor and normal cell lines, 3 did not show cytotoxicity against the same cells, while 4 showed higher cytotoxicity against cancer cell lines than lapachol (1). The transformation of 1 into harmless and reactive metabolites evidences the importance of the evaluation of drug metabolism in the drug discovery process. Antifungal potential of lapachol (1) and its metabolites 2 and 4 against B. cinerea has also been evaluated. Dehydro-α-lapachone (4) has been shown to be less toxic to fungal growth than lapachol (1), which indicates a detoxification mechanism of the phytopathogen.

New Non-Toxic Semi-Synthetic Derivatives from Natural Diterpenes Displaying Anti-Tuberculosis Activity.

We report herein the synthesis of six diterpene derivatives, three of which are new, generated through known organic chemistry reactions that allowed structural modification of the existing natural products kaurenoic acid (1) and copalic acid (2). The new compounds were fully characterized using high resolution mass spectrometry, infrared spectroscopy, ¹H- and (13)C-NMR experiments. We also report the evaluation of the anti-tuberculosis potential for all compounds, which showed some promising results for Micobacterium tuberculosis inhibition. Moreover, the toxicity for each of the most active compounds was also assessed.

Anti-parasitic Guanidine and Pyrimidine Alkaloids from the Marine Sponge Monanchora arbuscula.

HPLC-UV-ELSD-MS-guided fractionation of the anti-parasitic extract obtained from the marine sponge Monanchora arbuscula, collected off the southeastern coast of Brazil, led to the isolation of a series of guanidine and pyrimidine alkaloids. The pyrimidines monalidine A (1) and arbusculidine A (7), as well as the guanidine alkaloids batzellamide A (8) and hemibatzelladines 9-11, represent new minor constituents that were identified by analysis of spectroscopic data. The total synthesis of monalidine A confirmed its structure. Arbusculidine A (7), related to the ptilocaulin/mirabilin/netamine family of tricyclic guanidine alkaloids, is the first in this family to possess a benzene ring. Batzellamide A (8) and hemibatzelladines 9-11 represent new carbon skeletons that are related to the batzelladines. Evaluation of the anti-parasitic activity of the major known metabolites, batzelladines D (12), F (13), L (14), and nor-L (15), as well as of synthetic monalidine A (1), against Trypanosoma cruzi and Leishmania infantum is also reported, along with a detailed investigation of parasite cell-death pathways promoted by batzelladine L (14) and norbatzelladine L (15).

Elevated micronucleus frequency in patients with type 2 diabetes, dyslipidemia and periodontitis.

The over-production of reactive oxygen species (ROS) can cause oxidative damage to a large number of molecules, including DNA, and has been associated with the pathogenesis of several disorders, such as diabetes mellitus (DM), dyslipidemia and periodontitis (PD). We hypothesise that the presence of these diseases could proportionally increase the DNA damage. The aim of this study was to assess the micronucleus frequency (MNF), as a biomarker for DNA damage, in individuals with type 2 DM, dyslipidemia and PD. One hundred and fifty patients were divided into five groups based upon diabetic, dyslipidemic and periodontal status (Group 1 - poor controlled DM with dyslipidemia and PD; Group 2 - well-controlled DM with dyslipidemia and PD; Group 3 - without DM with dyslipidemia and PD; Group 4 - without DM, without dyslipidemia and with PD; and Group 5 - without DM, dyslipidemia and PD). Blood analyses were carried out for fasting plasma glucose, HbA1c and lipid profile. Periodontal examinations were performed, and venous blood was collected and processed for micronucleus (MN) assay. The frequency of micronuclei was evaluated by cell culture cytokinesis-block MN assay. The general characteristics of each group were described by the mean and standard deviation and the data were submitted to the Mann-Whitney, Kruskal-Wallis, Multiple Logistic Regression and Spearman tests. The Groups 1, 2 and 3 were similarly dyslipidemic presenting increased levels of total cholesterol, low density lipoprotein cholesterol and triglycerides. Periodontal tissue destruction and local inflammation were significantly more severe in diabetics, particularly in Group 1. Frequency of bi-nucleated cells with MN and MNF, as well as nucleoplasmic bridges, were significantly higher for poor controlled diabetics with dyslipidemia and PD in comparison with those systemically healthy, even after adjusting for age, and considering Bonferroni's correction. Elevated frequency of micronuclei was found in patients affected by type 2 diabetes, dyslipidemia and PD. This result suggests that these three pathologies occurring simultaneously promote an additional role to produce DNA impairment. In addition, the micronuclei assay was useful as a biomarker for DNA damage in individuals with chronic degenerative diseases.

Chemical composition, antischistosomal and cytotoxic effects of the essential oil of Lavandula angustifolia grown in Southeastern Brazil

This paper reports on the chemical composition, the in vitro antischistosomal effects, and the cytotoxicity of the essential oil from the leaves of Lavandula angustifolia Mill., Lamiaceae, grown in the Southeastern Brazil. Borneol (22.4%), epi-α-muurolol (13.4%), α-bisabolol (13.1%), precocene I (13.0%), and eucalyptol (7.9%) were the major essential oil constituents. Incubation with essential oil at 200 μg/ml killed all the adult S. mansoni worms after 24 h (LC50 117.7 and 103.9 μg/ml at 24 and 120 h of incubation, respectively). At a concentration of 50 μg/ ml, the essential oil significantly decreased the motor activity and reduced the percentage of egg development after 120 h. In addition, the essential oil separated all the coupled S. mansoni worm pairs into individual male and female at 25 and 50 μg/ml within 120 and 24 h, respectively. This oil was cytotoxic to GM07492-A cells at only concentrations higher than 200 µg/ml (IC50 243.7 µg/ml). These data indicate that LA-EO exhibits moderate in vitro activity against adult S. mansoni and exerts remarkable effects on eggs development.

RP-HPLC analysis of manool-rich Salvia officinalis extract and its antimicrobial activity against bacteria associated with dental caries

In this paper we screened the dichloromethane extract from the aerial parts of Salvia officinalis L., Lamiaceae, against a representative panel of microorganisms that cause caries, conducted a bioassay-guided fractionation to establish themselves the most active metabolite (manool) and determined the Salvia officinalis fraction with the manool highest concentration to be used to activate an ingredient in oral care products such as toothpastes and mouthwashes. Both manool and S. officinalis extract showed very promising minimal inhibitory concentration values (between 6.24 and 31.36 µg.ml-1) and time kill curves against the primary causative agents of dental caries (Streptococcus mutans) revealed that, at twice its minimal bactericidal concentration (12.48 µg.ml-1), manool required 6 h to completely kill the bacteria. Salvia officinalis extract at twice its minimal bactericidal concentration (31.36 µg.ml-1 ) needed 12 h. The results achieved with Salvia officinalis extract motivated us to develop and validate an analytical RP-HPLC method to detect and determine manool in this extract. The validation parameters were satisfactorily met and evaluated allows us to consider the developed method suitable for use in different labs. In conclusion, our results evidenced that the manool-rich S. officinalis extract can be considered an analytically validated alternative to develop novel and effective antimicrobial agents against the main bacteria responsible for dental caries.

In vitro antimicrobial activity of plant-derived diterpenes against bovine mastitis bacteria.

We evaluated the antibacterial activity of three diterpenes isolated from natural sources against a panel of microorganisms responsible for bovine mastitis. ent-Copalic acid (CA) was the most active metabolite, with promising MIC values (from 1.56 to 6.25 µg mL-1) against Staphylococcus aureus (ATCC and clinical isolate), Staphylococcus epidermidis, Streptococcus agalactiae, and Streptococcus dysgalactiae. We conducted time-kill assays of CA against S. aureus, a commensal organism considered to be a ubiquitous etiological agent of bovine mastitis in dairy farms worldwide. In the first 12 h, CA only inhibited the growth of the inoculums (bacteriostatic effect), but its bactericidal effect was clearly noted thereafter (between 12 and 24 h). In conclusion, CA should be considered for the control of several Gram-positive bacteria related to bovine mastitis.

Antimutagenic effect of aqueous extract from Agaricus brasiliensis on culture of human lymphocytes.

The mushroom Agaricus brasiliensis (sun mushroom), native from the southeast of Brazil, is well known by its medicinal properties that include effects on diabetes, cholesterol levels, and osteoporosis. The antimutagenic effects of A. brasiliensis has been investigated recently and revealed some controversial results depending on the temperature by which the A. brasiliensis tea is obtained. In the present study, we evaluated the effect of the A. brasiliensis extract prepared in two different temperatures, 4°C and 25°C, on the doxorubicin-induced DNA strand breaks and chromosomal aberrations (CAs) in human lymphocytes. The results demonstrated that A. brasiliensis was able to reduce the DXR-induced DNA damage in both temperatures; however, the CA test was more sensitive to demonstrate a better reduction when the cells were treated with an extract obtained at 25°C. A. brasiliensis extract obtained in different temperatures exhibited antigenotoxic and anticlastogenic effects in human lymphocytes.

Pimarane-type diterpenes obtained by biotransformation: antimicrobial properties against clinically isolated Gram-positive multidrug-resistant bacteria.

The present study describes the antimicrobial activity of five pimarane-type diterpenes obtained by fungal biotransformation against several nosocomial multidrug-resistant bacteria. Among the investigated metabolites, ent-8(14),15-pimaradien-3ß-ol was the most active compound, with very promising minimal inhibitory concentration values (between 8.0 and 25.0 µg mL(-1)). Time-kill assays using this metabolite against Staphylococcus aureus (HCRP180) revealed that this compound exerted its bactericidal effect within 24 h at all the evaluated concentrations (8.0, 16.0, and 24.0 µg mL(-1)). When this metabolite was associated with vancomycin at their minimal bactericidal concentration values, the resulting combination was able to drastically reduce the number of viable strains of S. aureus within the first 6 h, compared with these chemicals alone. The checkerboard assays conducted against this microorganism did not evidence any synergistic effects when this same combination was employed. In conclusion, our results point out that ent-8(14),15-pimaradien-3ß-ol is an important metabolite in the search for new effective antimicrobial agents.