RESUMO
Chagas disease, African trypanosomiasis and Leishmaniasis are neglected parasitic diseases which affect millions of people worldwide. In a previous work, we report the antiprotozoal activity of the dichloromethane extract of Mikania periplocifolia Hook. & Arn. (Asteraceae). The aim of this work was to isolate and identify the bioactive compounds present in the extract. The fractionation of the dichloromethane extract has led to the isolation of the sesquiterpene lactone miscandenin and the flavonoid onopordin, together with the sesquiterpene lactones mikanolide, dihydromikanolide and deoxymikanolide, which have previously shown antiprotozoal activity. Miscandenin and onopordin were assayed in vitro against Trypanosoma cruzi, T. brucei and Leishmania braziliensis. Miscandenin was active against T. cruzi trypomastigotes and amastigotes with IC50 values of 9.1 and 7.7 µg/ml, respectively. This sesquiterpene lactone and the flavonoid onopordin showed activity against T. brucei trypomastigotes (IC50 = 0.16 and 0.37 µg/ml) and L. braziliensis promastigotes (IC50 = 0.6 and 1.2 µg/ml), respectively. The CC50 values on mammalian cells were 37.9 and 53.4 µg/ml for miscandenin and onopordin, respectively. Besides, the pharmacokinetic and physicochemical properties of miscandenin were assessed in silico, showing a good drug-likeness profile. Our results highlight this compound as a promising candidate for further preclinical studies in the search of new drugs for the treatment of trypanosomiasis and leishmaniasis.
Assuntos
Antiprotozoários , Asteraceae , Leishmaniose , Mikania , Sesquiterpenos , Trypanosoma cruzi , Animais , Humanos , Asteraceae/química , Mikania/química , Cloreto de Metileno/uso terapêutico , Extratos Vegetais/química , Estrutura Molecular , Antiprotozoários/farmacologia , Leishmaniose/tratamento farmacológico , Flavonoides/farmacologia , Lactonas , MamíferosRESUMO
The extract obtained from Mikania glomerata leaves rich in ent-kaurenoic acid (ERKA) shows cytotoxic activity in vitro, but its hydrophobic nature and thermosensitivity are issues to be solved prior to in vivo antitumor studies. The purpose of this study was to investigate the antitumor activity of inclusion complexes formed between ERKA and ß-cyclodextrin (ERKA:ß-CD) in rodents. ERKA:ß-CD complexes obtained by malaxation (MX) and co-evaporation (CE) methods were firstly characterized regarding their physical properties, encapsulation efficiency, and cytotoxicity againts L929 cells. The antitumor activity study was then performed in mice with sarcoma 180 treated with saline, 5-fluouracil (5FU) and ERKA:ß-CD at 30, 100 and 300 µg/kg. The weight, volume, percentage of inhibition growth, gross and pathological features and positivity for TUNEL, ki67, NFκB and NRF2 in the tumors were assessed. Serum lactate-dehydrogenase activity (LDH), white blood cells count (WBC) and both gross and pathological features of the liver, kidneys and spleen were also evaluated. The formation of the inclusion complexes was confirmed by thermal analysis and FTIR, and they were non-toxic for L929 cells. The MX provided a better complexation efficiency. ERKA:ß-CD300 promoted significant tumor growth inhibition, and attenuated the tumor mitotic activity and necrosis content, comparable to 5-fluorouracil. ERKA:ß-CD300 also increased TUNEL-detected cell death, reduced Ki67 and NF-kB immunoexpression, and partially inhibited the serum LDH activity. No side effect was observed in ERKA:ß-CD300-treated animals. The ERKA:ß-CD inclusion complexes at 300 µg/kg displays antitumour activity in mice with low systemic toxicity, likely due to inhibition on the NF-kB signaling pathway and LDH activity.
Assuntos
Mikania , Neoplasias , Sarcoma 180 , beta-Ciclodextrinas , Camundongos , Animais , Mikania/química , Sarcoma 180/tratamento farmacológico , NF-kappa B , Antígeno Ki-67 , beta-Ciclodextrinas/química , Desenvolvimento de MedicamentosRESUMO
The present study evaluated the effect of the essential oil of Mikania cordifolia (EOMc) and its major constituent limonene alone or associated with antibacterial drugs against Multidrug Resistant Bacteria (MDR). To evaluate the antibacterial activity, the minimum inhibitory concentrations (MIC) of the oil and limonene against Pseudomonas aeruginosa, Escherichia coli and Staphylococcus aureus were determined. The antibiotic-modulating activity was assessed using subinhibitory concentrations (MIC/8) of these substances in combination with conventional antibacterial drugs. Although no relevant antibacterial activity of the natural products was detected, both substances modulated the action of antibiotics against resistant bacteria. The EOMc demonstrated the best modulating effect against P. aeruginosa, presenting synergistic effects when associated with gentamicin and norfloxacin. In addition, the oil reduced the MIC of norfloxacin against E. coli as well as reduced the MIC of gentamicin against S. aureus. On the other hand, the best effect of limonene was obtained against S. aureus. Thus, it is concluded that the essential oil Mikania cordifolia and the isolated compound limonene do not have clinically significant antibacterial effect, but modulate the action of antibiotics against MDR bacteria.
Assuntos
Antibacterianos/farmacologia , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Limoneno/farmacologia , Mikania/química , Óleos Voláteis/farmacologia , Óleos de Plantas/farmacologia , Sinergismo Farmacológico , Escherichia coli/efeitos dos fármacos , Cromatografia Gasosa-Espectrometria de Massas , Gentamicinas/farmacologia , Testes de Sensibilidade Microbiana , Norfloxacino/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacosRESUMO
Mikania glomerata Sprengel, popularly known as "guaco," is used in Brazilian folk medicine for several inflammatory and allergic conditions. Besides, the popular use "guaco" is indicated by the Brazilian Ministry of Health as a safe and effective herbal medicine. The biological activity of M. glomerata extracts is due to the presence of the coumarins, a large family of phenolic substances found in plants and is made of fused benzene and α-pyrone rings. Considering that there are few data on the biological effects of the extracts of M. glomerata, mainly in genetic level, this work aims to evaluate, in vitro, the genotoxicity and coumarin production in M. glomerata in conventional and organic growing. The data showed that the organic culture system showed double the concentration of coumarin being significantly more productive than the conventional system. Besides, the results of comet assay suggest that extracts of M. glomerata cultivated in a conventional system was genotoxic, increased DNA damage levels while the organic extracts seem to have antigenotoxic effect possibly due to the concentration of coumarins. Additional biochemical investigations are necessary to elucidate the mechanisms of action of M. glomerata extracts, which were found to have a role in protection against DNA damage.
Assuntos
Agricultura/métodos , Cumarínicos/metabolismo , Mikania/metabolismo , Extratos Vegetais/toxicidade , Plantas Medicinais/metabolismo , Células Sanguíneas/citologia , Células Sanguíneas/efeitos dos fármacos , Brasil , Sobrevivência Celular/efeitos dos fármacos , Cumarínicos/toxicidade , Dano ao DNA/efeitos dos fármacos , Humanos , Mikania/química , Testes de Mutagenicidade , Agricultura Orgânica/métodos , Extratos Vegetais/análise , Extratos Vegetais/químicaRESUMO
INTRODUCTION: Mikania laevigata Sch.Bip. ex Baker and Mikania glomerata Spreng. are medicinal plants popularly known as guaco, used for inflammatory diseases of the respiratory system, included in pharmaceutical formularies and often used without distinction. However, several studies show that the chemical composition varies between these species, as well as in plants are subjected to different environmental stresses. Few studies have been carried out with the volatile compounds of guaco, even less about the changes in volatile composition due to abiotic variation. OBJECTIVE: The aim of this work was to evaluate how volatile compounds vary according to the seasons and at different times of the day and if these compounds are influenced by the variations in the growth conditions such as: temperature, luminosity and water. METHODS: The headspace volatiles of the leaves were sampled by solid phase micro extraction and analyzed by gas chromatography-mass spectrometry. Untargeted metabolomic analysis of the resulting chromatograms and chemometrics was applied. The chemical profile of the volatiles of M. laevigata and M. glomerata were different; being clearly separated in the exploratory grouping analyzes (PCA), followed by analysis of variance of the marker compounds of both species. RESULTS: Only M. laevigata contained coumarin, considered to be the chemical marker of both species and to be responsible for the therapeutic activities. There was no significant difference between the morning and afternoon collections of either species. Coumarin, α-pinene and bicyclogermacrene were more intense in the volatiles of M. laevigata throughout the year and responsible for grouping the samples of this species. For M. glomerata, hexanal and 2-hexenal were responsible for grouping the samples and were more intense in all months. The growth conditions tested affected the intensity of specific compounds in the chromatograms. Some compounds were less intense with the increase of the temperature and in the plants subjected to full sunlight. However, certain volatile compounds-such as pinenes-were more intense in plants suffering drought. CONCLUSION: The variation in composition between species of guaco was greater than those observed in the seasonal and cultivation studies, indicating that these species cannot be used indistinctly.
Assuntos
Mikania/metabolismo , Plantas Medicinais/metabolismo , Compostos Orgânicos Voláteis/metabolismo , Monoterpenos Bicíclicos/análise , Monoterpenos Bicíclicos/metabolismo , Brasil , Cumarínicos/análise , Cumarínicos/metabolismo , Secas , Mikania/química , Plantas Medicinais/química , Sesquiterpenos de Germacrano/análise , Sesquiterpenos de Germacrano/metabolismo , Estresse Fisiológico , Temperatura , Compostos Orgânicos Voláteis/análiseRESUMO
BACKGROUND: Deoxymikanolide is a sesquiterpene lactone isolated from Mikania micrantha and M. variifolia which, has previously demonstrated in vitro activity on Trypanosoma cruzi and in vivo activity on an infected mouse model. PURPOSE: Based on these promising findings, the aim of this study was to investigate the mechanism of action of this compound on different parasite targets. METHODS: The interaction of deoxymikanolide with hemin was examined under reducing and non- reducing conditions by measuring modifications in the Soret absorption band of hemin; the thiol interaction was determined spectrophotometrically through its reaction with 5,5'-dithiobis-2-nitrobenzoate in the presence of glutathione; activity on the parasite antioxidant system was evaluated by measuring the activity of the superoxide dismutase and trypanothione reductase enzymes, together with the intracellular oxidative state by flow cytometry. Superoxide dismutase and trypanothione reductase activities were spectrophotometrically tested. Cell viability, phosphatidylserine exposure and mitochondrial membrane potential were assessed by means of propidium iodide, annexin-V and rhodamine 123 staining, respectively; sterols were qualitatively and quantitatively tested by TLC; ultrastructural changes were analyzed by transmission electron microscopy. Autophagic cells were detected by staining with monodansylcadaverine. RESULTS: Deoxymikanolide decreased the number of reduced thiol groups within the parasites, which led to their subsequent vulnerability to oxidative stress. Treatment of the parasites with the compound produced a depolarization of the mitochondrial membrane even though the plasma membrane permeabilization was not affected. Deoxymikanolide did not affect the intracellular redox state and so the mitochondrial dysfunction produced by this compound could not be attributed to ROS generation. The antioxidant defense system was affected by deoxymikanolide at twenty four hours of treatment, when both an increased oxidative stress and decreased activity of superoxide dismutase and trypanothione reductase (40 and 60% respectively) were observed. Both the oxidative stress and mitochondrial dysfunction induce parasite death by apoptosis and autophagy. CONCLUSION: Based on our results, deoxymikanolide would exert its anti-T cruzi activity as a strong thiol blocking agent and by producing mitochondrial dysfunction.
Assuntos
Lactonas/farmacologia , Sesquiterpenos de Germacrano/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Autofagia/efeitos dos fármacos , Glutationa/metabolismo , Hemina/metabolismo , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mikania/química , NADH NADPH Oxirredutases/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Esteróis/biossíntese , Superóxido Dismutase/metabolismo , Trypanosoma cruzi/patogenicidade , Trypanosoma cruzi/ultraestruturaRESUMO
Statistical mixture design extraction and fractionation of Mikania plant samples were carried out to quantitatively study seasonal and solvent composition effects as well as their interactions on secondary metabolites. The mixture design consisted of ethanol, acetone, dichloromethane and chloroform solvents and their binary, ternary and quaternary mixtures. Yields were measured for the crude extract and its neutral, organic, basic, polar and fiber fractions obtained with each solvent composition from samples harvested during 2010. Two-way ANOVA found statistically significant seasonal and solvent effects for the crude extract and all the fractions except for the polar fraction solvent. The best solvent extractor depends the harvest season. High crude, organic and polar fraction yields in the summer are correlated with the coumarin UV-vis absorbance at 274â¯nm. Crude yields of mixtures containing ethanol are correlated with the coumarin absorbances in summer, winter and spring whereas mixtures without ethanol show no significant correlation.
Assuntos
Mikania/química , Folhas de Planta/química , Solventes/química , Fracionamento Químico , Cumarínicos/análise , Cumarínicos/química , Alimento Funcional , Mikania/metabolismo , Extratos Vegetais/química , Folhas de Planta/metabolismo , Estações do Ano , Metabolismo SecundárioRESUMO
AIM: To evaluate the antibacterial activity of 12 kaurane-type diterpenes against a panel of bacteria that cause endodontic infection. METHODS & MATERIALS: We conducted tests against bacteria in the planktonic or in the sessile mode, cytotoxic assays for the most promising compounds against human normal lung fibroblast cells, and Porphyromonas gingivalis (ATCC 33277) proteomic analysis. RESULTS & CONCLUSION: Kaurenoic acid and its salt exhibited satisfactory antibacterial action against the evaluated bacteria. Proteomic analysis suggested that these compounds might interfere in bacterial metabolism and virulence factor expression. Kaurane-type diterpenes are an important class of natural products and should be considered in the search for new irrigating solutions to treat endodontic infections.
Assuntos
Antibacterianos/farmacologia , Infecções por Bacteroidaceae/tratamento farmacológico , Diterpenos/farmacologia , Porphyromonas gingivalis/efeitos dos fármacos , Antibacterianos/química , Infecções por Bacteroidaceae/microbiologia , Biofilmes/efeitos dos fármacos , Diterpenos/química , Humanos , Viabilidade Microbiana/efeitos dos fármacos , Mikania/química , Extratos Vegetais/química , Folhas de Planta/química , Porphyromonas gingivalis/crescimento & desenvolvimento , Porphyromonas gingivalis/isolamento & purificação , Pulpite/tratamento farmacológico , Pulpite/microbiologiaRESUMO
Mikania glomerata and Mikania laevigata are medicinal plants popularly used in Brazil for colds and asthma. Although several studies report differences in their composition, they are frequently used indistinctly, which may be due to misidentification of the species or the plant part used. Herein, the chemical, anatomical, and morphological profiles of both species were evaluated, seeking to differentiate them. Due to the pattern of secondary metabolites found in M. glomerata and M. laevigata, the chemical profile of the leaves was the characteristic that best differentiated the two species. Coumarin was present in all the leaf samples of M. laevigata but absent or in low concentration in leaf samples of M. glomerata. The stems presented coumarin in both species, albeit in different concentrations. The quantification of chlorogenic and dicaffeoylquinic acids was crucial for the separation of the two species, as higher concentrations are found in M. glomerata. The anatomic structure of the leaves, stem, and petioles of both species was conserved, even when exposed to different environments, but presented only subtle differences between species. The morphology of the leaves presented different characteristics for each species but altered when exposed to shade. Therefore, the chemical analysis together with the morphological characteristics of plants grown in full sunlight may be used for the correct identification of these species.
Assuntos
Mikania/classificação , Mikania/anatomia & histologia , Mikania/química , Mikania/ultraestrutura , Plantas Medicinais/anatomia & histologia , Plantas Medicinais/química , Plantas Medicinais/classificação , Plantas Medicinais/ultraestrutura , Especificidade da EspécieRESUMO
Gamma irradiation as a decontaminating physical agent could be an important tool in the production chain of herbal medicines by improving the microbiological quality of raw materials and the safety of final products. This study was undertaken to investigate the genotoxic potential and eventual chemical modifications of a batch of Mikania glomerata raw material decontaminated by different doses of gamma irradiation (2.0, 3.5, and 5.0 kGy), using a cesium-137 source. DNA damage was assessed in vitro by agarose gel electrophoresis in regard to double-chain breaks of plasmid pUC 9.1 DNA and in vivo by micronucleus test in bone marrow cells of Wistar rats. Cytotoxicity in bone marrows was assessed by scoring polychromatic and normochromatic erythrocytes ratio. An HPLC-DAD method was adapted and validated for the enhancement of coumarin selectivity from the other matrix constituents. The microbial load was satisfactorily reduced, leading to sterilization at the highest dose. Genotoxic and cytotoxic effects were not increased in the in vitro and in vivo models. The concentration of coumarin and the chromatographic profiles of the hydroalcoholic plant extracts (ethanol 70% v/v) were not modified after such process. Therefore, this work suggests that gamma irradiation of M. glomerata raw material is suitable and safe for microbiological control purposes at the employed doses.
Assuntos
Dano ao DNA/efeitos dos fármacos , Descontaminação/métodos , Mikania/química , Extratos Vegetais/efeitos da radiação , Folhas de Planta/efeitos da radiação , Animais , Medula Óssea/efeitos dos fármacos , Cromatografia Líquida de Alta Pressão/métodos , Cumarínicos , Eletroforese em Gel de Ágar , Raios gama , Masculino , Testes para Micronúcleos , Mikania/microbiologia , Extratos Vegetais/toxicidade , Folhas de Planta/química , Folhas de Planta/microbiologia , Ratos WistarRESUMO
Four sesquiterpene lactones, mikanolide, deoxymikanolide, dihydromikanolide and scandenolide, were isolated by a bioassay-guided fractionation of Mikania variifolia and Mikania micrantha dichloromethane extracts. Mikanolide and deoxymikanolide were the major compounds in both extracts (2.2% and 0.4% for Mikania variifolia and 21.0% and 6.4% for Mikania micrantha respectively, calculated on extract dry weight). Mikanolide, deoxymikanolide and dihydromikanolide were active against Trypanosoma cruzi epimastigotes (50% inhibitory concentrations of 0.7, 0.08 and 2.5 µg/mL, for each compound respectively). These sesquiterpene lactones were also active against the bloodstream trypomastigotes (50% inhibitory concentrations for each compound were 2.1, 1.5 and 0.3 µg/mL, respectively) and against amastigotes (50% inhibitory concentrations for each compound were 4.5, 6.3 and 8.5 µg/mL, respectively). By contrast, scandenolide was not active on Trypanosoma cruzi. Besides, mikanolide and deoxymikanolide were also active on Leishmania braziliensis promastigotes (50% inhibitory concentrations of 5.1 and 11.5 µg/mL, respectively). The four sesquiterpene lactones were tested for their cytotoxicity on THP 1 cells. Deoxymikanolide presented the highest selectivity index for trypomastigotes (SI = 54) and amastigotes (SI = 12.5). In an in vivo model of Trypanosoma cruzi infection, deoxymikanolide was able to decrease the parasitemia and the weight loss associated to the acute phase of the parasite infection. More importantly, while 100% of control mice died by day 22 after receiving a lethal T. cruzi infection, 70% of deoxymikanolide-treated mice survived. We also observed that this compound increased TNF-α and IL-12 production by macrophages, which could contribute to control T. cruzi infection.
Assuntos
Lactonas/farmacologia , Leishmania braziliensis/efeitos dos fármacos , Mikania/química , Extratos Vegetais/farmacologia , Sesquiterpenos/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Doença de Chagas/tratamento farmacológico , Doença de Chagas/parasitologia , Descoberta de Drogas , Interleucina-12/biossíntese , Interleucina-12/imunologia , Lactonas/administração & dosagem , Lactonas/química , Lactonas/isolamento & purificação , Lactonas/uso terapêutico , Estágios do Ciclo de Vida/efeitos dos fármacos , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Extratos Vegetais/química , Sesquiterpenos/química , Sesquiterpenos/isolamento & purificação , Sesquiterpenos de Germacrano/administração & dosagem , Sesquiterpenos de Germacrano/isolamento & purificação , Sesquiterpenos de Germacrano/farmacologia , Sesquiterpenos de Germacrano/uso terapêutico , Trypanosoma cruzi/isolamento & purificação , Fator de Necrose Tumoral alfa/biossíntese , Fator de Necrose Tumoral alfa/imunologiaRESUMO
The search for new, effective and safe antimicrobial compounds from plant sources has continued to play an important role in the maintenance of human health since ancient times. Such compounds can be used to help to eradicate microorganisms from the root canal system, preventing/healing periapical diseases. Mikania glomerata (Spreng.), commonly known as "guaco," is a native climbing plant from Brazil that displays a wide range of pharmacological properties. Many of its activities have been attributed to its phytochemical composition, which is mainly composed of diterpenes, such as ent-kaurenoic acid (KA). The present study evaluated the potential activity of an ent-kaurenoic-rich (KA) extract from Mikania glomerata (i.e. Mikania glomerata extract/MGE) and its major compound KA against bacteria that can cause endodontic infections. Time-kill assays were conducted and the minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC), anti-biofilm activity, and synergistic antimicrobial activity of MGE and KA were determined. The MGE exhibited MIC and MBC values, which ranged from 6.25 to 100 µg/mL and 12.5 to 200 µg/mL respectively. The MIC and MBC results obtained for the KA, ranged from 3.12 to 100 µg/mL and 3.12 to 200 µg/mL respectively. Time-kill and anti-biofilm activity assays conducted for KA at concentrations between 3.12 and 12.5 µg/mL exhibited bactericidal activity between 6 and 72 h of incubation and 50% inhibition of biofilm formation for Porphyromonas gingivalis (clinical isolate), Propionibacterium acnes (ATCC 6919), Prevotella nigrescens (ATCC 33563), P. melaninogenica (ATCC 25845), Aggregatibacter actinomycetemcomitans (ATCC 43717). For synergistic antimicrobial activity, KA combined with chlorhexidine dichlorohydrate (CHD) had an additive effect with increased efficacy against P. gingivalis (clinical isolate) compared to CHD alone. It was concluded that M. glomerata extract and its major compound ent-kaurenoic acid (KA) showed in vitro antibacterial activity, the latter being a potential biofilm inhibitory agent. They may play important roles in the search for novel sources of agents that can act against bacteria present in endodontic infections.
Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Infecções Bacterianas/microbiologia , Diterpenos/farmacologia , Mikania/química , Extratos Vegetais/farmacologia , Pulpite/microbiologia , Antibacterianos/isolamento & purificação , Bactérias/isolamento & purificação , Biofilmes/efeitos dos fármacos , Brasil , Clorexidina/farmacologia , Diterpenos/isolamento & purificação , Sinergismo Farmacológico , Humanos , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Extratos Vegetais/isolamento & purificaçãoRESUMO
Coumarin, o-coumaric, and kaurenoic acid are bioactive compounds usually found in the leaves of Mikania laevigata. Genetic and environmental variations in the secondary metabolites of plants may have implications for their biological effects. Three different accessions of M. laevigata cultivated in four sites between the Equator and the Tropic of Capricorn in Brazil were evaluated aiming to present potential raw materials and discuss relationships among these three bioactive compounds. The results revealed effects of plant accessions and environmental factors and suggested two contrasting chemical phenotypes of M. laevigata. The first phenotype presented the highest levels of kaurenoic acid (2283 ± 316 mg/100 g) besides lower levels of coumarin (716 ± 61 mg/100 g), which was also stimulated by the environment and mild climate at the site nearest to the Tropic of Capricorn. The other phenotype presented the lowest levels of kaurenoic acid (137 ± 17 mg/100 g) besides higher levels of coumarin (1362 ± 108 mg/100 g), which was also stimulated by the environment and tropical climate at the site nearest to the Equatorial beach.
Assuntos
Cumarínicos/análise , Diterpenos/análise , Mikania/química , Ácidos Cumáricos/análise , Meio Ambiente , FenótipoRESUMO
Many studies have reported that medicinal plant extracts can inhibit oral pathogen growth or adhesion to surfaces and therefore reduce dental caries formation. The addition of these extracts to oral products like mouthwashes and dentifrices is considered an important strategy in caries control. In this sense, we have developed a Mikania glomerata extract with high ent-kaurenoic acid content (KAMg). So, this work describes the preparation of such extract and the development of a validated HPLC-DAD method to determine its ent-kaurenoic acid (KA) content. Herein it is also described the KAMg in vitro antibacterial evaluation against several cariogenic bacteria in comparison with KA and the investigation of further aspects of the KAMg activity. Toxicological aspects of the developed extract were evaluated by assessing its cytotoxicity and genotoxicity. KA and a KA-rich extract like KAMg showed to inhibit the growth of microorganisms responsible for dental caries at relatively low MIC (Minimum inhibitory concentration) values, albeit not as low as the MIC value obtained for chlorhexidine digluconate (CHD), the golden anticariogenic standard approved by the American Dental Association Council on Dental Therapeutics. However, KAMg was more effective to inhibit the formation of a Streptococcus mutans biofilm with four times lower MICB50 (minimum inhibitory concentration that reduces 50% of the biofilm) value as compared with CHD. Taking into account all these data and considering the absence of genotoxic and cytotoxic activity under the tested conditions, it is suggested that KAMg is a natural product to be considered as active ingredient in oral care products.
Assuntos
Antibacterianos/farmacologia , Biofilmes/efeitos dos fármacos , Diterpenos/farmacologia , Mikania/química , Streptococcus mutans/efeitos dos fármacos , Animais , Cárie Dentária/microbiologia , Masculino , Camundongos , Testes de Sensibilidade Microbiana , Componentes Aéreos da Planta/química , Extratos Vegetais/farmacologia , Testes de ToxicidadeRESUMO
For decades guaco species have been empirically used for the treatment of respiratory diseases. However, studies have shown that the toxic and therapeutic effects of the main guaco metabolites are dose-dependent, and none clinical study was done to evaluate the behavior of these substances in humans. In this work, a pilot study measuring the kinetic profile of the main guaco metabolites was performed leading to the knowledge of an alternative route of coumarin metabolism in humans. Initial screenings demonstrated that the administration of 60 mL of guaco syrup (single dose) did not provide sufficient levels of coumarin (COU), 7-hydroxycoumarin (7-HCOU), o-coumaric acid (OCA) and kaurenoic acid (KAU). The pharmacokinetic parameters were calculated by orally administering 60 mL of guaco syrup spiked with 1500 mg of COU. The kinetic study demonstrated that the plasmatic levels of 7-HCOU (considered the main metabolite of COU) were 10 times lower than the levels of COU, and the kinetic profile of 7-HCOU suggests sequential metabolism in the liver with low access of 7-HCOU to the systemic circulation. The study also demonstrated that OCA is one of the main bioavailable metabolites of COU. Therefore, the hydrolysis of the lactone ring forming a carboxylated compound is one of the possible routes of COU metabolism in humans. The half-lives of COU, 7-HCOU and OCA were approximately 4.0, 1.0 and 3.0 h, respectively and there was evidence that the recommended dosage of guaco syrup did not provide sufficient levels of COU, 7-HCOU or OCA to obtain a bronchodilation effect. Clinical studies are necessary to prove the efficacy and safety of products based on guaco.
Assuntos
Cumarínicos/farmacocinética , Mikania/química , Extratos Vegetais/farmacocinética , Medicamentos para o Sistema Respiratório/farmacocinética , Administração Oral , Adulto , Cumarínicos/administração & dosagem , Combinação de Medicamentos , Avaliação Pré-Clínica de Medicamentos , Feminino , Humanos , Masculino , Extratos Vegetais/administração & dosagem , Medicamentos para o Sistema Respiratório/administração & dosagem , Umbeliferonas/administração & dosagem , Umbeliferonas/farmacocinética , Adulto JovemRESUMO
Statistical design mixtures of acetone, chloroform, dichloromethane and ethanol were used to study the effects of different solvents and their mixtures on the quantities of coumarin and related metabolites extracted from Mikania laevigata samples harvested in each of the four seasons. RP-HPLC-DAD and both positive and negative modes of UPLC-MS analyses were used to determine relative quantities of coumarin, o-coumaric acid and melilotic acids in each season for all the mixture design extracts. The existence and measurement of the relative abundances of melilotic acid in Mikania laevigata have not been reported previously. Highest coumarin concentrations were encountered in the summer whereas its o-coumaric acid precursor and melilotic acid were most abundant in the spring. O-coumaric and melilotic acids concentrations were strongly correlated during the year. Also solvent effects were seen to be significant. Ethanol and 1:1 binary mixtures of ethanol and acetone extracted the largest quantities of coumarin whereas ethanolic binary and ternary mixtures with chloroform and dichloromethane provided the best yields of o-coumaric and melilotic acids. Statistical mixture models indicated that synergic binary interactions, especially those involving ethanol with acetone or chloroform, are important in the Mikania extraction process.
Assuntos
Cumarínicos/análise , Mikania/química , Extratos Vegetais/química , Folhas de Planta/química , Cromatografia Líquida de Alta Pressão , Cromatografia de Fase Reversa , Cumarínicos/isolamento & purificação , Cumarínicos/metabolismo , Espectrometria de Massas , Mikania/metabolismo , Extratos Vegetais/metabolismo , Folhas de Planta/metabolismo , Estações do Ano , Solventes/químicaRESUMO
The guaianolide 8-epi-mikanokryptin (1) and the melampolide 11Hß-11,13-dihydromicrantholide (2) along with known sesquiterpene lactones (3-13) and other constituents were isolated from the aerial parts of different populations of Mikania micrantha and Mikania cordifolia collected in several states of Mexico. The relative and absolute configurations of 1 were determined by X-ray diffraction and CD analysis, respectively. Considering the (1)H and (13)C NMR chemical shift similarities and the H-H coupling constant values, a [(1)D(14), (15)D5] conformation was established for micrantholides (2, 8-13). We tested nearly all the sesquiterpene lactones for antiproliferative activity in human cancer cell lines, and they exhibited moderate activity. Additionally, in a mouse ear model of edema induced by TPA, the anti-inflammatory activities were marginal.
Assuntos
Anti-Inflamatórios/química , Lactonas/química , Mikania/química , Extratos Vegetais/química , Sesquiterpenos/química , Animais , Anti-Inflamatórios/isolamento & purificação , Anti-Inflamatórios/farmacologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Cristalografia por Raios X , Modelos Animais de Doenças , Edema , Humanos , Concentração Inibidora 50 , Lactonas/isolamento & purificação , Lactonas/farmacologia , Espectroscopia de Ressonância Magnética , Camundongos , Estrutura Molecular , Componentes Aéreos da Planta/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Sesquiterpenos/isolamento & purificação , Sesquiterpenos/farmacologia , Sesquiterpenos de Guaiano/química , Sesquiterpenos de Guaiano/isolamento & purificação , Sesquiterpenos de Guaiano/farmacologiaRESUMO
Populations of the same species vary in their secondary metabolite content. This variation has been attributed to biotic and abiotic environmental conditions as well as to historical factors. Some studies have focused on the geographic variation of chemical diversity in plant populations, but whether this structure conforms to a central-marginal model or a mosaic pattern remains unclear. Furthermore, assessing the chemical diversity of invasive plants in their native distribution facilitates the understanding of their relationships with natural enemies. We examined the geographic variation of chemical diversity in Mexican populations of the bittervine weed Mikania micrantha and its relationship to herbivore damage. The foliar volatile terpenoid blend was analyzed in 165 individuals of 14 populations in the Pacific and Gulf of Mexico tropical watersheds. A cluster analysis grouped individuals with similar terpenoid blends into 56 compositional types. Chemical diversity was measured using the number of compounds and their concentration within the blends for individuals, and the number and frequency of compositional types for populations. A stepwise multiple regression analysis performed with geographic, climatic, and chemical diversity variables explained herbivore damage. However, population-level chemical diversity was the only variable found to be significant (ß = -0.79, P = 0.042) in the model (R(2) = 0.89). A Mantel test using Euclidean distances did not indicate any separation by geographic origin; however, four barriers were identified using Monmonier's algorithm. We conclude that variation in population-level chemical diversity follows a mosaic pattern in which geographic factors (i.e., natural barriers) have some effect and that variation is also associated with the local intensity of herbivore attack.
Assuntos
Herbivoria , Mikania/química , Animais , Geografia , México , Folhas de Planta/química , Metabolismo Secundário , Terpenos/análiseRESUMO
The leaves of Mikania laevigata and Mikania glomerata are used in Brazil to treat respiratory affections, being kaurane-type diterpenes and coumarin considered as the bioactive compounds. The present study reports an investigation on the HPLC-DAD profiles and contents of coumarin (1), trans-o-coumaric (2), kaurenoic (3), benzoylgrandifloric (4) and cinnamoylgrandifloric (5) acids in dried leaves of Mikania species stored in dark room under controlled conditions. Excepting 2, the constituents were isolated and purified to be employed as reference compounds. The samples were analyzed at three monthly intervals up to 18 months for M. laevigata and 12 months for M. glomerata. trans-o-Coumaric was not detected in both, whereas 1 occurred only in M. laevigata. The concentrations of the assayed constituents did not vary significantly within the evaluated period (p < 0.05), for both species. In contrast, changes in the chromatographic profiles and spectral purity of peaks from 3, 4 and 5 were detected in samples of both Mikania stored for three months, while the coumarin profile in M. laevigata modified after six months of storage. The evaluation of chromatographic profiles based on spectral purity analyses of selected peaks was shown to be a more robust tool to access chemical stability of Mikania samples than the quantitation of chemical markers' contents.
Assuntos
Cinamatos/isolamento & purificação , Diterpenos do Tipo Caurano/isolamento & purificação , Mikania/química , Extratos Vegetais/química , Cromatografia Líquida de Alta Pressão , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Fatores de TempoRESUMO
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.