In silico and in vitro evaluation of efflux pumps inhibition of α,ß-amyrin.

The use of the bacterial efflux pump mechanism to reduce the concentrations of antibiotics in the intracellular to the extracellular region is one of the main mechanisms by which bacteria acquire resistance to antibiotics. The present study aims to evaluate the antibacterial activity of the α,ß-amyrin mixture isolated from Protium heptaphyllum against the multidrug-resistant strains of Escherichia coli 06 and Staphylococcus aureus 10, and to verify the inhibition of the efflux resistance mechanisms against the strains of S. aureus 1199B and K2068, carrying the NorA and MepA efflux pumps, respectively. The α,ß-amyrin did not show clinically relevant direct bacterial activity. However, the α,ß-amyrin when associated with the gentamicin antibiotic presented synergistic effect against the multidrug-resistant bacterial strain of S. aureus 10. In strains with efflux pumps, α,ß-amyrin was able to inhibit the action of the efflux protein NorA against Ethidium Bromide. However, this inhibitory effect was not observed in the MepA efflux pump. In addition, when evaluating the effect of standard efflux pump inhibitors, clorptomazine and CCCP, α,ß-amyrin showed a decrease in MIC, demonstrating the presence of the efflux mechanism through synergism. Docking studies indicate that α, ß-amyrin have a higher affinity energy to MepA, and NorA than ciprofloxacin and norfloxacin. Also, α, ß-amyrin bind to the same region of the binding site as these antibiotics. It was concluded that the α, ß-amyrin has the potential to increase antibacterial activity with the association of antibiotics, together with the ability to be a strong candidate for an efflux pump inhibitor.Communicated by Ramaswamy H. Sarma.

A new heterofunctional support for enzyme immobilization: PEI functionalized Fe3O4 MNPs activated with divinyl sulfone. Application in the immobilization of lipase from Thermomyces lanuginosus.

Lipase from Thermomyces lanuginosus (TLL) was immobilized onto a novel heterofunctional support, divinyl sulfone (DVS) superparamagnetic nanoparticles (SPMNs) functionalized with polyethyleneimine (PEI). Particle size and zeta potential measurements, elemental analysis, X-ray powder diffraction, magnetic measurements, and infrared spectroscopy analysis were used to characterize the TLL preparations. At pH 10, it was possible to achieve 100 % of immobilization yield in 1 h. The immobilization pH gives TLL preparations with different stabilities; indeed the TLL preparation immobilized at pH 5.0 was the most stable during the thermal inactivation at all pH values. For the hydrolysis of racemic methyl mandelate, the nanobiocatalysts immobilized at pH 5.0 and blocked with ethylenediamine (EDA) and ethanolamine (ETA) obtained good enantioselectivities (68 % and 72 %, respectively) with high catalytic activities in the reaction medium at pH 7.0. The operational stability of the systems was evaluated in the esterification reaction of benzyl alcohol, obtaining up to 61 % conversion after the seventh reaction cycle. These results show that SPMN@PEI-DVS support is a robust strategy for the easy and rapid recovery of the nanobiocatalyst by applying a magnetic field, showing great potential for industrial applications.

Chemical composition and biological activities of the essential oils from Vitex-agnus castus, Ocimum campechianum and Ocimum carnosum.

The essential oils obtained by hydrodistillation from fresh leaves of Vitex agnus-castus and Ocimum campechianum, and from fresh inflorescences of Ocimum carnosum were analysed by GC-FID and GC-MS. The major components of V. agnus-castus essential oil were identified as 1,8-cineole (47.9%), terpinyl α-acetate (11.6%), sabinene (11.2%) and caryophyllene oxide (9.7%), while in the O. campechianum essential oil were eugenol (72.1%), ß-elemene (6.8%), (E)-caryophyllene (6.4%) and bicyclogermacrene (5.2%). Linalool (79.0%), α-epi-cadinol (5.4%), terpinen-4-ol (3.2%) and 1,8-cineole (2.8%) were the major constituents in the O. carnosum essential oil. The essential oils were subsequently evaluated for their larvicidal and cytotoxic activities. Larval bioassay against Aedes aegypti of V. agnus-castus, O. campechianum and O. carnosum essential oils showed LC50 values of 97.55 ± 0.35, 81.45 ± 0.35 and 109.49 ± 0.35 µg/mL, respectively. The in vitro cytotoxic activities of the essential oils has been evaluated on breast adenocarcinoma (MCF-7), lung carcinoma (NCI-H292), pro-myelocytic leukemia (HL-60), and cervical adenocarcinoma (HEP-2) human cell lines, and pro-myelocytic leukemia cells lines (HL-60) were found to be the most sensitive to all the essential oils tested than the others. This is the first report on larvicidal and cytotoxic activities of these essential oils.

Biflorin inhibits the proliferation of gastric cancer cells by decreasing MYC expression.

Gastric cancer is the third leading cause of cancer-related death worldwide. To evaluate the anticancer potential and molecular mechanism of biflorin, a prenyl-ortho-naphthoquinone obtained from Capraria biflora L. roots, we used ACP02, a gastric cancer cell line established from a primary diffuse gastric adenocarcinoma. In this study, biflorin was shown to be a potent cytotoxic agent against ACP02 by Alamar Blue and Trypan Blue assays. Morphological analysis indicated cell death with features of necrosis. Furthermore, a decrease in colony formation, migration and invasion of ACP02 cells was observed after treatment with biflorin (1.0, 2.5 and 5.0 µM). Regarding the underlying molecular mechanism of biflorin in ACP02 cells, we observed a decrease in MYC expression and telomere length using FISH. Our findings suggest a novel molecular target of biflorin in ACP02 cells, which may be a significant therapeutic approach for gastric cancer management.

Antibiotic-Potentiating Activity of Phanostenine Isolated from Cissampelos sympodialis Eichler.

Cissampelos sympodialis Eichler is well studied and investigated for its antiasthmatic properties, but there are no data in the literature describing antibacterial properties of alkaloids isolated from this botanical species. This work reports the isolation and characterization of phanostenine obtained from roots of C. sympodialis and describes for the first time its antimicrobial and antibiotic modulatory properties. Phanostenine was first isolated from Cissampelos sympodialis and its antibacterial activities were determined. Chemical structures of the alkaloid isolate were determined using spectroscopic and chemical analyses. Phanostenine was also tested for its antibacterial activity against standard strains and clinical isolates of Escherichia coli and Staphylococcus aureus. Minimal inhibitory concentration (MIC) was determined in a microdilution assay and for the evaluation of antibiotic resistance-modifying activity. MIC of the antibiotics was determined in the presence or absence of phanostenine at sub-inhibitory concentrations. The evaluation of antibacterial activity by microdilution assay showed activity for all strains with better values against S. aureus ATCC 12692 and E. coli 27 (787.69 mm). The evaluation of aminoglycoside antibiotic resistance-modifying activity showed reduction in the MIC of the aminoglycosides (amikacin, gentamicin and neomycin) when associated with phanostenine, MIC reduction of antibiotics ranging from 21 % to 80 %. The data demonstrated that phanostenine possesses a relevant ability to modify the antibiotic activity in vitro. We can suggest that phanostenine presents itself as a promising tool as an adjuvant for novel antibiotics formulations against bacterial resistance.

Synthesis of Benzyl Acetate Catalyzed by Lipase Immobilized in Nontoxic Chitosan-Polyphosphate Beads.

Enzymes serve as biocatalysts for innumerable important reactions, however, their application has limitations, which can in many cases be overcome by using appropriate immobilization strategies. Here, a new support for immobilizing enzymes is proposed. This hybrid organic-inorganic support is composed of chitosan-a natural, nontoxic, biodegradable, and edible biopolymer-and sodium polyphosphate as the inorganic component. Lipase B from Candida antarctica (CALB) was immobilized on microspheres by encapsulation using these polymers. The characterization of the composites (by infrared spectroscopy, thermogravimetric analysis, and confocal Raman microscopy) confirmed the hybrid nature of the support, whose external part consisted of polyphosphate and core was composed of chitosan. The immobilized enzyme had the following advantages: possibility of enzyme reuse, easy biocatalyst recovery, increased resistance to variations in temperature (activity declined from 60 °C and the enzyme was inactivated at 80 °C), and increased catalytic activity in the transesterification reactions. The encapsulated enzymes were utilized as biocatalysts for transesterification reactions to produce the compound responsible for the aroma of jasmine.

Chemical constituents from Bauhinia acuruana and their cytotoxicity

ABSTRACT Phytochemical investigation of Bauhinia acuruana Moric., Fabaceae, resulted in the isolation of sixteen constituents, including two new compounds 2'-hydroxy-2,3,5-trimethoxybibenzyl (1), (2R,3S)-2-(3,4'-dihydroxyphenyl)-5-methoxy-6-methylchroman-3,7-diol (2), together with fourteen known ones (3-16). The structures of the compounds were established by spectroscopic analysis including HR-ESI-MS, 1D and 2D NMR data, followed by comparison with previously reported data from the literature. Compounds 1, 2, 6, 7, 8 and 9 were evaluated for their cytotoxicity, which turned out to be marginal in a panel of six human cancer cell lines.

7-epi-griffonilide, a new lactone from Bauhinia pentandra: complete 1H and 13C chemical shift assignments.

A new lactone, 7-epi-griffonilide (1), and six known compounds, 2, 3a - 3c, 4a and 4b, were isolated from the leaves of Bauhinia pentandra (Fabaceae). The structures elucidation of 1 and 2 were based on detailed 2D NMR techniques and spectral comparison with related compounds, leading to complete assignment of the 1H and 13C NMR spectra.

7-epi-griffonilide, a new lactone from Bauhinia pentandra: complete 1H and 13C chemical shift assignments

ABSTRACT A new lactone, 7-epi-griffonilide (1), and six known compounds, 2, 3a - 3c, 4a and 4b, were isolated from the leaves of Bauhinia pentandra (Fabaceae). The structures elucidation of 1 and 2 were based on detailed 2D NMR techniques and spectral comparison with related compounds, leading to complete assignment of the 1H and 13C NMR spectra.

New Cytotoxic Bibenzyl and Other Constituents from Bauhinia ungulata L. (Fabaceae).

A new bibenzyl, 2'-hydroxy-3,5-dimethoxy-4-methylbibenzyl (1) and four known compounds identified as 2'-hydroxy-3,5-dimethoxybibenzyl (2), liquiritigenin (3), guibourtinidol (4) and fisetinidol (5) were isolated from the roots of Bauhinia ungulata L. Phytochemical investigations of the stems of B. ungulata led to the isolation of the known compounds identified as liquiritigenin (3), guibourtinidol (4), fisetinidol (5), taraxerol (6), betulinic acid (7), taraxerone (8), glutinol (9), a mixture of sitosterol (10) and stigmasterol (11), pacharin (12), naringenin (13) and eriodictyol (14). The structures of these compounds were elucidated on the basis of their spectral data (IR, MS, 1D- and 2D-NMR). The cytotoxicity of the bibenzyl 1 has been evaluated against four human cancer cell lines, showing the IC50 values of 4.3 and 6.5 µg ml-1 against pro-myelocytic leukemia (HL-60) and cervical adenocarcinoma (HEP-2) cell lines, respectively. This article also registers for the first time the 13 C-NMR data of the known bibenzyl 2.

Synthesis, antibacterial and cytotoxic activities of new biflorin-based hydrazones and oximes.

Biflorin 1 is a biologically active quinone, isolated from Capraria biflora. Five new biflorin-based nitrogen derivatives were synthesized, of which two were mixtures of (E)- and (Z)- isomers: (Z)-2a, (Z)-2b, (Z)-3a, (Z)- and (E)-3b, (Z)- and (E)-3c. The antibacterial activity was investigated using the microdilution method for determining the minimum inhibitory concentration (MIC) against six bacterial strains. Tests have shown that these derivatives have potential against all bacterial strains. The cytotoxic activity was also evaluated against three strains of cancer cells, but none of the derivatives showed activity.

Chemical composition of the essential oil and fixed oil Bauhinia pentandra (Bong.) D. Dietr.

BACKGROUND: Bauhinia pentandrais popularly known as "mororó" and inhabits the Caatinga and Savannah biomes. OBJECTIVE: This paper reports the chemical composition of the essential and fatty oils of the leaves from B. pentandra. MATERIALS AND METHODS: The essential oil was obtained by hydrodistillation and the fixed oil by extraction with hexane, followed by saponification with KOH/MeOH, and methylation using MeOH/HCl. The constituents were analyzed by gas chromatography-mass spectrometry. RESULTS: The major constituent of the essential oil was the phytol (58.78% ±8.51%), and of the fatty oil were palmitic (29.03%), stearic (28.58%) and linolenic (10.53%) acids. CONCLUSION: Of the compounds identified in the essential oil, three are first reported in this species, and this is the first record of the chemical composition of the fixed oil.

Lithocholic acid and derivatives: Antibacterial activity.

In order to develop bioactive lithocholic acid derivatives, we prepared fifteen semi-synthetic compounds through modification at C-3 and/or C-24. The reactions showed yields ranging from 37% to 100%. The structures of all compounds obtained were identified on the basis of their spectral data (IR, MS, 1D- and 2D-NMR). The activity of lithocholic acid and derivatives was evaluated against the growth of Escherichia coli, Staphylococcus aureus, Bacillus cereus and Pseudomonas aeruginosa. The derivative 3α-formyloxy-5ß-cholan-24-oic acid (LA-06) showed the best activity, with MIC values of 0.0790 mM against E. coli (Ec 27) and B. cereus in both cases, and 0.0395 mM against S. aureus (ATCC 12692). Lithocholic acid and the derivatives with MIC⩽1.2 mM were evaluated on the susceptibility of some bacterial pathogens to the aminoglycoside antibiotics neomycin, amikacin and gentamicin was evaluated. There are no previously reported studies about these compounds as modifiers of the action of antibiotics or any other drugs.

Antibacterial and antioxidant activities of ursolic acid and derivatives.

Ursolic acid, an important bioactive compound, was isolated from ethanol extract of aerial parts of Sambucus australis. In order to develop bioactive ursolic acid derivatives, two semi-synthetic compounds were obtained through modification at C-3. The antibacterial activity of the ursolic acid and its derivatives was investigated. The microdilution method was used for determination of the minimal inhibitory concentration (MIC), against twelve bacterial strains. The influence of ursolic acid and its derivatives on the susceptibility of some bacterial pathogens to the aminoglycosides antibiotics neomycin, amikacin, kanamycin and gentamicin was evaluated. The most representative synergistic effect was observed by 3ß-formyloxy-urs-12-en-28-oic acid at the concentration of 64 µg/mL in combination with kanamycin against Escherichia coli (27), a multidrug-resistant clinical isolate from sputum, with reduction of MIC value from 128 µg/mL to 8 µg/mL. Ursolic acid and its derivatives were examined for their radical scavenger activity using the DPPH assay, and showed significant activity.

Biflorin: an o-naphthoquinone of clinical significance.

Biflorin is an o-naphthoquinone with proven cytotoxic effects on tumor cells showing antimicrobial, antitumor and antimutagenic activities. Biflorin is an isolated compound taken from the roots of the plant Capraria biflora L. (Schrophulariaceae), indigenous of the West Indies and South America, which is located in temperate or tropical areas. This compound has shown to be strongly active against grampositive and alcohol-acid-resistant bacteria. It has been efficient in inhibiting the proliferation tumor cell lines CEM, HL-60, B16, HCT-8 and MCF-7. Recently, SK-Br3 cell line was treated with biflorin showing important cytotoxic effects. In this article, information related to the first structural characterization studies are presented, as well as the latest reports concerning the biological activity of this molecule.

Magnetic nanosystem for cancer therapy using oncocalyxone a, an antitomour secondary metabolite isolated from a Brazilian plant.

This paper describes the investigation and development of a novel magnetic drug delivery nanosystem (labeled as MO-20) for cancer therapy. The drug employed was oncocalyxone A (onco A), which was isolated from Auxemma oncocalyx, an endemic Brazilian plant. It has a series of pharmacological properties: antioxidant, cytotoxic, analgesic, anti-inflammatory, antitumor and antiplatelet. Onco A was associated with magnetite nanoparticles in order to obtain magnetic properties. The components of MO-20 were characterized by XRD, FTIR, TGA, TEM and Magnetization curves. The MO-20 presented a size of about 30 nm and globular morphology. In addition, drug releasing experiments were performed, where it was observed the presence of the anomalous transport. The results found in this work showed the potential of onco A for future applications of the MO-20 as a new magnetic drug release nanosystem for cancer treatment.

A novel o-naphtoquinone inhibits N-cadherin expression and blocks melanoma cell invasion via AKT signaling.

The down-regulation or loss of epithelial markers is often accompanied by the up-regulation of mesenchymal markers. E-cadherin generally suppresses invasiveness, whereas N-cadherin promotes invasion and metastasis in vitro. The aim of this work is to investigate the role of biflorin, a naphthoquinone with proven anticancer properties, on the expression of N-cadherin and AKT proteins in MDA-MB-435 invasive melanoma cancer cells after 12h of exposure to 1, 2.5 and 5 µM biflorin. Biflorin inhibited MDA-MB-435 invasion in a dose-dependent manner (p<0.01). Likewise, biflorin down-regulated N-cadherin and AKT-1 expression in a dose-dependent manner. Biflorin did not inhibit the adhesion of MDA-MB-435 cells to any tested substrates. Additionally, biflorin blocked the invasiveness of cells by down-regulating N-cadherin, most likely via AKT-1 signaling. As such, biflorin may be a novel anticancer agent and a new prototype for drug design.

Larvicidal activity against Aedes aegypti of essential oils from northeast Brazil.

The larvicidal activities of essential oils from the leaves of Artemisia vulgaris L., Cymbopogon flexuosus (Nees ex Steud.) Wats. and Piper tuberculatum Jacq. were evaluated using third-instar larvae of Aedes aegypti. The essential oils were obtained by hydrodistillation and analyzed by GC and GC-MS. The essential oil of P. tuberculqatum had the lowest LC50 value (106.3 +/- 2.2 microg/mL), followed by that of A. vulgaris (114.1 +/- 1.7 microg/mL) and C. flexuosus (121.6 +/- 0.8 micro/mL). The results show that these essential oils may be potent sources of natural larvicides.

New indole alkaloid from Peschiera affinis (Apocynaceae).

A new indole alkaloid of the pyridocarbazole type, named 6N-hydroxy-olivacine, and two known compounds, 2N-oxide-olivacine and olivacine, were isolated from roots of Peschiera affinis. The structures of the compounds were determined by spectroscopic {IR and extensive NMR (COSY, HMQC, HMBCand NOESY)} and EIMS analysis.

Ursolic acid, a pentacyclic triterpene from Sambucus australis, prevents abdominal adiposity in mice fed a high-fat diet.

Currently, there is renewed interest in plant-based medicines and functional foods for the prevention and cure of obesity and its associated risk of cardiovascular disease and metabolic syndrome. In the search for potential anti-obesity compounds from natural sources, the effects of ursolic acid (UA), a pentacyclic triterpenoid widely found in medicinal herbs and fruits, was evaluated for its effects on blood glucose, lipids, and abdominal fat deposition in mice fed a high-fat diet (HFD). Adult male Swiss mice treated or not with UA (0.05%, 50 mg/L, in drinking water) were fed HFD for 15 weeks. A sibutramine (SIB)-treated group (0.05% in drinking water) was included as the positive control. Weekly body weights and food and water consumption were measured, and at the end of the study period, the levels of blood glucose and lipids, the plasma hormones insulin, ghrelin, and leptin, and the abdominal fat accumulation were analyzed. Mice treated with UA and fed HFD showed significantly (P<.05) decreased body weights, visceral adiposity, and levels of blood glucose and plasma lipids relative to their respective controls not fed UA. Also, a significant increase was observed in plasma leptin with a decrease in ghrelin, as well as of amylase and lipase activities. The SIB-treated group also manifested effects similar to those of UA except for the blood glucose level, which was not different from the HFD control. These findings suggest that UA ameliorates abdominal adiposity and decreases the levels of blood glucose and plasma lipids in mice and thus manifests an anti-obesity potential through absorptive and metabolic targets.