RESUMO
Over the last decade, much research has focused on the potential health benefits of antioxidants and indeed many synthetic and natural compounds have been evaluated for their antioxidant profile. However, in several studies only a limited number of assays, often poorly validated, are used and the techniques available frequently lack specificity. These limitations may incorrectly influence the results. This review will therefore focus on several pitfalls that may emerge in vitro and in vivo antioxidant research. First, different in vitro techniques to determine antioxidant potential are discussed, including radical scavenging assays and fingerprinting methods. As a rule, a panel of different assays is indispensable to characterize and establish in vitro antioxidant activity. Furthermore, as problems of absorption, distribution, metabolism and excretion are only accounted for by in vivo studies, the need for in vivo antioxidant research is pointed out. Several methods to characterize the in vivo activity of antioxidants, including major drawbacks and pitfalls of some assays, have been discussed. The availability of both a representative "oxidative stress" animal model and a battery of well-validated assays to assess the broad diversity of oxidative damage and antioxidative defence parameters, are crucial for antioxidant research in vivo.
Assuntos
Antioxidantes/uso terapêutico , Pesquisa Biomédica , Avaliação Pré-Clínica de Medicamentos/métodos , Animais , Antioxidantes/farmacocinética , Antioxidantes/farmacologia , Humanos , Estresse Oxidativo/efeitos dos fármacosRESUMO
The ethanolic extracts from fresh apical stems of Phyllanthus niruri L. (Euphorbiaceae) cultured on Murashige and Skoog (MS) medium supplemented with IBA/BAP/Coco nucifera L. milk for 1, 2, 4 and 6 months were phytochemically and biologically investigated and compared with intact plant part and whole plant extracts. Results from the in vitro antiplasmodial testing indicated that the EtOH extract of a 1-month-old callus culture (IC(50) = 16.3 +/- 2.5 microg/ml) exhibited a higher activity than the ethanolic extracts of the fresh apical stem (IC(50) = 18.2 +/- 2.4 microg/ml) and callus cultures of 2-, 4- and 6-months-old (25 microg/ml < IC(50) < 40 microg/ml). These activities were however lower than that displayed by the ethanolic extract of the whole plant (IC(50) < 3 microg/ml). The EtOH extract of 1-month-old callus culture (the most active) was fractionated with solvents of different polarities. Its CH(2)Cl(2) fraction rich in terpenic constituents (IC(50) = 9.2 +/- 3.4 microg/ml) exhibited a higher antiplasmodial activity than its isoamylic alcohol fraction obtained at pH 2-3 (IC(50) = 25.6 +/- 2.3 microg/ml) rich in flavonoids. The activity of these two fractions was lower than that displayed by the same fractions from the whole plant (2 microg/ml < IC(50) < 3 microg/ml). Alkaloidic fractions from the whole plant and 1-month-old callus culture of fresh apical stem were considered as inactive (IC(50) > 100 microg/ml).
Assuntos
Antimaláricos/farmacologia , Phyllanthus , Plasmodium falciparum/efeitos dos fármacos , Animais , Antimaláricos/isolamento & purificação , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Caules de Planta , Plasmodium falciparum/fisiologiaRESUMO
The in vitro antiplasmodial activity of seven EtOH extracts and twenty fractions from the partition of the initial ethanolic extracts from seven African medicinal plants used in the Democratic Republic of Congo (DR Congo) for the treatment of malaria was evaluated. The most active EtOH extracts (IC50 < 3 microg/ml) were those from Cassia occidentalis leaves, Euphorbia hirta whole plant, Garcinia kola stem bark and Phyllanthus niruri whole plant. Their respective petroleum ether soluble fractions also exhibited an antiplasmodial activity with IC50 < 3 microg/ml. EtOH extracts from Vernonia amygdalina leaves (5 < IC50 < 10 microg/ml), Tetracera poggei leaves (10 < IC50 < 50 microg/ml) and Morinda morindoides leaves (50 < IC50 < 100 microg/ml) were less active, but their petroleum ether fractions exhibited a pronounced antiplasmodial activity (IC50 < 3 microg/ml). The same observation could also be made for the petroleum ether fraction from Cassia occidentalis, Euphorbia hirta, Garcinia kola and Phyllanthus niruri. Isoamyl alcohol fractions from Euphorbia hirta, Phyllanthus niruri and Vernonia amygdalina showed IC50) values less than 3 microg/ml, and from Cassia occidentalis, Garcinia kola, Morinda morindoides and Tetracera poggei between 10 and 50 microg/ml. The observed antiplasmodial activity may be related to the presence of terpenes, steroids, coumarins, flavonoids, phenolic acids, lignans, xanthones and anthraquinones.
Assuntos
Antimaláricos/farmacologia , Plantas Medicinais , Plasmodium falciparum/efeitos dos fármacos , Animais , Antimaláricos/isolamento & purificação , República Democrática do Congo , Humanos , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Estruturas Vegetais , Plasmodium falciparum/fisiologiaRESUMO
Polyphenolic compounds are widely distributed in higher plants and are an integral part of the human diet. Recent interest in these substances has been stimulated by their potential health benefits, which are believed to arise mainly from their antioxidant activity. In the past years, the antioxidant activity of flavonoids has been studied in detail. An important but often overlooked group of polyphenols is that of the proanthocyanidins. Therefore, the present review is focused mainly on the antioxidant activity of proanthocyanidins and its relevancy in vivo. The three most important mechanisms of their antioxidant action will be discussed, i.e. free radical scavenging activity, chelation of transition metals, and inhibition of enzymes. In addition, the protective role of proanthocyanidins against lipid peroxidation and peroxynitrite, as well as their antimicrobial properties will be discussed. To study the in vivo relevancy of the proanthocyanidin activities, the knowledge of their pharmacokinetic parameters is crucial. Although bioavailability and metabolism data on polyphenols in general and proanthocyanidins in particular are still largely unavailable, the first reports indicate that at least monomers and smaller oligomeric procyanidins are absorbed. There is also considerable scientific and public interest in the important role that antioxidants may play in health care, e.g. by acting as cancer chemopreventive and anti-inflammatory agents and by reducing risk of cardiovascular mortality. Each of these aspects will be discussed, with special attention to the role of proanthocyanidins on apoptosis, gene expression and transcription factors, such as NF-kappa B.
Assuntos
Proantocianidinas , Animais , Anti-Infecciosos/química , Anti-Infecciosos/metabolismo , Anti-Infecciosos/farmacologia , Antineoplásicos/química , Antineoplásicos/metabolismo , Antineoplásicos/farmacologia , Antioxidantes/química , Antioxidantes/metabolismo , Antioxidantes/farmacologia , Disponibilidade Biológica , Doenças Cardiovasculares/prevenção & controle , Dieta , Inibidores Enzimáticos/química , Inibidores Enzimáticos/metabolismo , Inibidores Enzimáticos/farmacologia , Humanos , Estrutura Molecular , Proantocianidinas/química , Proantocianidinas/metabolismo , Proantocianidinas/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Taninos/farmacologiaRESUMO
Eight antioxidants from five different polyphenolic classes (cinnamic acids, benzoic acids, flavonoids, proanthocyanidins and stilbenes), and the water-soluble vitamin E derivative trolox were examined for their antioxidant activity in-vitro. In addition, the compounds were tested for their cytotoxicity on growing fibroblasts and their inhibition of the classical pathway of the complement system. Procyanidin C1 was shown to be a good scavenger of both DPPH(*) and HO(*), and a strong inhibitor of lipid peroxidation and the classical pathway of the complement system. Consequently, procyanidin C1 was classified as the most promising antioxidant in-vitro of all compounds tested. In contrast, genistein exhibited a very low antioxidant activity in both the lipid peroxidation and the DPPH(*) scavenging assay, a high cytotoxicity and a low complement-inhibiting activity.
Assuntos
Antioxidantes/farmacologia , Flavonoides/farmacologia , Fenóis/farmacologia , Antioxidantes/química , Benzoatos/farmacologia , Biflavonoides/química , Biflavonoides/farmacologia , Compostos de Bifenilo/química , Catequina/química , Catequina/farmacologia , Sobrevivência Celular/efeitos dos fármacos , Células Cultivadas , Cromanos/química , Cromanos/farmacologia , Cinamatos/farmacologia , Relação Dose-Resposta a Droga , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Flavonoides/química , Radicais Livres/metabolismo , Genisteína/química , Genisteína/farmacologia , Humanos , Hidrazinas/química , Radical Hidroxila/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Fenóis/química , Picratos , Polifenóis , Proantocianidinas/química , Proantocianidinas/farmacologia , Pele/citologia , Estilbenos/farmacologiaRESUMO
Forty-two ethanolic extracts of thirty-six Rwandan medicinal plants were investigated for their influence on complement-mediated hemolysis. The plants were selected on the base of their ethnomedicinal use in infections and autoimmune diseases. Eight plant extracts showed an inhibitory activity against the classical pathway of the complement system and ten plant extracts against the alternative pathway. Three plant extracts exhibited an interesting activity against both pathways, i.e. Aspilia pluriseta, Coleus kilimandschari, and Macaranga kilimandscharica (leaves and stem). Further study indicated that the complement inhibitory activity was not caused by chelation of bivalent cations or by direct action on the target erythrocytes.
Assuntos
Ativação do Complemento , Eritrócitos/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Medicinas Tradicionais Africanas , Fitoterapia , Extratos Vegetais/farmacologia , Humanos , Concentração Inibidora 50 , Estruturas Vegetais , RuandaRESUMO
Selected plants used in Rwandan traditional medicine for the treatment of infections and/or rheumatoid diseases were investigated for antiviral activity in vitro against human immunodeficiency virus type-1 (HIV-1). Of the 38 tested 80% ethanolic extracts, belonging to plants of 21 different families only the extracts from the leaves of Aspilia pluriseta (Asteraceae) and Rumex bequaertii (Polygonaceae) had interesting selectivity indices (SI = ratio of the 50% cytotoxic concentration to the 50% effective antiviral concentration) higher than 1. Further fractionation of the initially antivirally inactive ethanolic extract of Tithonia diversifolia, however, led to an aqueous fraction with a high anti-HIV-1 activity (SI > 461), indicating that the cytotoxicity of some plant components may mask the antiviral properties of the active plant substances in total plant extracts.
Assuntos
Fármacos Anti-HIV/farmacologia , HIV-1/efeitos dos fármacos , Medicinas Tradicionais Africanas , Fitoterapia , Extratos Vegetais/farmacologia , Fármacos Anti-HIV/uso terapêutico , Linhagem Celular/efeitos dos fármacos , Infecções por HIV/tratamento farmacológico , Humanos , Extratos Vegetais/uso terapêutico , Estruturas Vegetais , RuandaRESUMO
A total of 45 Rwandan plant extracts, belonging to 37 different plant species out of 21 families, were investigated for their antibacterial, antifungal, and antiviral properties. The plants were selected on the base of their ethnomedicinal use against infections and autoimmune diseases. From all the plant extracts tested, only Clematis hirsuta (leaves) showed a pronounced antifungal activity against Candida albicans and the dermatophytes Trichophyton rubrum, Epidermophyton floccosum, and Microsporum canis. Seven plant extracts showed a high antiviral activity against the DNA-virus Herpes simplex type 1, while five and three plant extracts were highly active against the RNA-viruses Coxsackie and Polio, respectively. Only Macaranga kilimandscharica (leaves) showed an interesting anti-measles activity, whereas Eriosema montanum (leaves) and Entada abyssinica (leaves) were highly active against Semliki forest virus. Some plant extracts showed an antibacterial activity against Gram-positive bacteria and Mycobacterium fortuitum, but none of them were active against the Gram-negative bacteria tested.
Assuntos
Anti-Infecciosos/farmacologia , Antivirais/farmacologia , Avaliação Pré-Clínica de Medicamentos/métodos , Medicinas Tradicionais Africanas , Extratos Vegetais/farmacologia , Antibacterianos , Anti-Infecciosos/uso terapêutico , Antifúngicos/farmacologia , Antifúngicos/uso terapêutico , Antivirais/uso terapêutico , Avaliação Pré-Clínica de Medicamentos/estatística & dados numéricos , Fitoterapia/métodos , Fitoterapia/estatística & dados numéricos , Extratos Vegetais/uso terapêutico , Folhas de Planta/química , RuandaRESUMO
The chemical composition of essential oils from 15 aromatic medicinal plant species growing in the Democratic Republic of Congo have been studied. More than 15 constituents in an amount higher than 0.1% were identified in each essential oil. 1,8-cineole, alpha and beta-pinene, p-cymene, myrcene, gamma-terpinene, alpha-terpineol and limonene were prevalent constituents in almost more than 10 selected plant species. Results from the antibacterial testing by the diffusion method indicate that all essential oils (5 microl per disc) inhibited the growth of selected bacteria at different extents. The most active antibacterial essential oils were those of the leaves of Eucalyptus camadulensis and Eucalyptus terticornis (12-30 mm zone diameter of inhibition). They showed particularly a most potent inhibition of Pseudomonas aeruginosa growth (15-16 mm), followed by Eucalyptus robusta (12 mm). Essential oils from the leaves of Eucalyptus alba, Eucalyptus citriodora, Eucalyptus deglupta, Eucalyptus globulus, Eucalyptus saligna, Eucalyptus robusta, Aframomum stipulatum, Cymbopogon citratus, Ocimum americanum and that of the seeds of Monodora myristica showed also a good antibacterial activity (10-18 mm). Eucalyptus propinqua, Eucalyptus urophylla and Ocimum gratissimum essential oils were the less active samples against the selected bacteria. No correlation between the amount of major constituents such as 1,8-cineol, alpha-pinene, p-cymene, cryptone or thymol and the antibacterial activity was observed.
Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Medicinas Tradicionais Africanas , Óleos Voláteis/química , Óleos Voláteis/farmacologia , Antibacterianos/uso terapêutico , República Democrática do Congo , Avaliação Pré-Clínica de Medicamentos/métodos , Avaliação Pré-Clínica de Medicamentos/estatística & dados numéricos , Bactérias Gram-Negativas/crescimento & desenvolvimento , Bactérias Gram-Positivas/crescimento & desenvolvimento , Óleos Voláteis/uso terapêutico , Fitoterapia/métodos , Fitoterapia/estatística & dados numéricos , Sementes/químicaRESUMO
Thirty-five flavonoids of seven different types, namely isoflavonoids, chalcones, dihydroflavonols, flavanols, flavanones, flavones, and flavonols were investigated for their ability to inhibit ascorbate-induced microsomal lipid peroxidation and their cytotoxicity. For each activity a structure-activity relationship was established. Subsequently, an antioxidant selectivity index, i. e., the maximal non-toxic dose divided by the IC(50) value for lipid peroxidation, was introduced. Kaempferol showed the highest antioxidant selectivity index of all flavonoids tested.
Assuntos
Antioxidantes/farmacologia , Flavonoides/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Microssomos Hepáticos/efeitos dos fármacos , Animais , Células Cultivadas , Fibroblastos/efeitos dos fármacos , Flavonoides/antagonistas & inibidores , Flavonoides/química , Flavonoides/farmacologia , Humanos , Concentração Inibidora 50 , Masculino , Ratos , Ratos Wistar , Pele/efeitos dos fármacos , Relação Estrutura-AtividadeRESUMO
Bridelia ferruginea Benth. (Euphorbiaceae) is a subtropical medicinal plant widely used in traditional African medicine against various diseases, including rheumatic pains. Seven of its constituents (3-O-methylquercetin (1), 3,7,3',4'-tetra-O-methylquercetin (rutisin, 2), myricetin (3), 3',4',5'-tri-O-methylmyricetin (ferrugin, 4), 3,3',4',5'-tetra-O-methylmyricetin (5), quercetin 3-O-glucoside (6), and a biflavanol gallocatechin-[4'-O-7]-epigallocatechin (7)) have been evaluated in-vitro in the xanthine-xanthine oxidase enzymatic system for inhibition of xanthine oxidase and radical scavenging activity. Results indicated that compounds 1, 3, 4 and 6 exhibited, at different levels, xanthine oxidase inhibiting and superoxide scavenging activity at micromolar concentrations, whereas compound 7 showed scavenging activity only. Compounds 2 and 5 were inactive in both cases. Study of the structure-activity relationship demonstrated that for flavonoids the xanthine oxidase inhibitory activity was reduced by methylation of the hydroxyl functionality at C-3 and in rings A and B. These results may partly explain and support the use of B. ferruginea stem bark for the treatment of rheumatic pains in traditional medicine.
Assuntos
Sequestradores de Radicais Livres/farmacologia , Fenóis/farmacologia , Xantina Oxidase/metabolismo , Artrite Reumatoide/tratamento farmacológico , Humanos , Medicinas Tradicionais Africanas , Fenóis/isolamento & purificação , Extratos Vegetais , Plantas Medicinais , Xantina Oxidase/efeitos dos fármacosRESUMO
The ethanolic, dichloromethane and lyophilized aqueous extracts of Cassia occidentalis root bark, Morinda morindoides leaves and whole plants of Phyllanthus niruri were evaluated for their antimalarial actvity in vivo, in 4-day, suppressive assays against Plasmodium berghei ANKA in mice. No toxic effect or mortality was observed in mice treated, orally, with any of the extracts as a single dose, of 500 mg/kg body weight, or as the same dose given twice weekly for 4 weeks (to give a total dose of 4 g/kg). No significant lesions were observed, by eye or during histopathological examinations, in the hearts, lungs, spleens, kidneys, livers, large intestines or brains of any mouse. At doses of 200 mg/kg, all the ethanolic and dichloromethane extracts produced significant chemosuppressions of parasitaemia (of > 60% for C. occidentalis root bark and Ph. niruri whole plant, and of 30% for M. morindoides leaves) when administered orally. The most active ethanolic extract, that of Ph. niruri, reduced parasitaemia by 73%. The dichloromethane extracts of M. morindoides and Ph. niruri produced similar reductions (74% and 72% chemosuppression, respectively), whereas that of C. occidentalis was slightly less active (60% chemosuppression). Each lyophilized aqueous extract was less active than the corresponding ethanolic extract.
Assuntos
Cassia/uso terapêutico , Euphorbiaceae/uso terapêutico , Malária/tratamento farmacológico , Fitoterapia , Plantas Medicinais , Plasmodium berghei/efeitos dos fármacos , Rubiaceae/uso terapêutico , Administração Oral , Animais , Camundongos , Extratos Vegetais/uso terapêutico , Folhas de Planta , Raízes de Plantas , Resultado do TratamentoRESUMO
The aim of this study was to investigate whether there is one conflict management style that correlated more significantly with marital satisfaction than any other. In addition, spousal satisfaction with how marital conflict is managed was also examined, as were gender differences. Fifty-seven couples who had been married for at least 10 years took part in the study. Results showed that the collaborative conflict management style has the highest correlation with both marital satisfaction and spousal satisfaction with conflict management in the marriage. In contrast, where one or both of the spouses used the competitive conflict management style, the lowest marital satisfaction was reported. The results were also interpreted in terms of cultural and gender differences.
Assuntos
Conflito Psicológico , Casamento/psicologia , Satisfação Pessoal , Feminino , Humanos , Masculino , Inquéritos e QuestionáriosRESUMO
Three major extracts from some traditional preparations, based on medicinal plants, used as antidiarrhoeal agents were investigated for their putative antiamoebic and spasmolytic activities in vitro. Results indicated that both biological activities are concentrated in the polyphenolic fraction, and not in the saponin or alkaloid containing fractions. The most active polyphenolic extracts were those from Euphorbia hirta whole plant, leaves of Alchornea cordifolia, Crossopteryx febrifuga, Nauclea latifolia, Psidium guajava, Tithonia diversifolia, stem bark of Harungana madagascariensis, Mangifera indica, Maprounea africana and Psidium guajava, inhibiting Entamoeba histolytica growth with MAC < 10 micrograms/ml. The same extracts, at a concentration of 80 micrograms/ml in an organ bath, also exhibited more than 70% inhibition of acetylcholine and/or KCl solution-induced contractions on isolated guinea-pig ileum.
Assuntos
Amebicidas/farmacologia , Antidiarreicos/farmacologia , Medicinas Tradicionais Africanas , Parassimpatolíticos/farmacologia , Extratos Vegetais/farmacologia , Plantas Medicinais , Animais , República Democrática do Congo , Entamoeba histolytica/efeitos dos fármacos , Feminino , Cobaias , Íleo/efeitos dos fármacos , Masculino , Testes de Sensibilidade Microbiana , Contração Muscular/efeitos dos fármacosRESUMO
In addition to the known sterols and ketosteroids beta-sitosterol (24 alpha-ethylcholest-5-en-3 beta-ol), stigmasterol (24 alpha-ethylcholesta-5,22-dien-3 beta-ol), campesterol (24 alpha-methylcholest-5-en-3 beta-ol), beta-sitostenone (stigmast-4-en-3-one, 24 alpha-ethylcholest-4-en-3-one), stigmastenone (stigmasta-4,22-dien-3-one, 24 alpha-ethylcholesta-4,22-dien-3-one), campestenone (24 alpha-methylcholest-4-en-3-one), and stigmasta-3,5-dien-7-one (24 alpha-ethylcholesta-3,5-dien-7-one), the new steroids stigmasta-3,5,22-trien-7-one (24 alpha-ethylcholesta-3,5,22-trien-7-one), and campesta-3,5-dien-7-one (24 alpha-methylcholesta-3,5-dien-7-one) were isolated from the stem bark of Harrisonia abyssinica and identified by NMR and mass spectrometry.
Assuntos
Plantas Medicinais/química , Esteroides/isolamento & purificação , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Estrutura Molecular , Esteroides/químicaRESUMO
A series of dimeric procyanidins (1-9) and some related polyphenols (10-15) were chosen as model compounds in a comparative investigation for various biological activities in order to obtain structure-activity relationships. Antiviral [herpes simplex virus (HSV) and human immunodeficiency virus (HIV)], antibacterial, superoxide radical-scavenging, and complement-modulating properties were assessed. In general, more pronounced activities were seen with epicatechin-containing dimers for anti-HSV, anti-HIV, and radical-scavenging effects, while the presence of ortho-trihydroxyl groups in the B-ring was important in compounds exhibiting anti-HSV and radical-scavenging effects and complement classical pathway inhibition. Double interflavan linkages gave rise to interesting antiviral effects (HSV and HIV) and complement inhibition. The influence of the degree of polymerization or the type of interflavan linkage (4-->6 or 4-->8) differed in the different biological systems evaluated. Only minor or moderate antibacterial effects were observed for the compounds under investigation.
Assuntos
Antocianinas/farmacologia , Anti-Infecciosos/farmacologia , Antivirais/farmacologia , Proteínas Inativadoras do Complemento/farmacologia , Flavonoides , Sequestradores de Radicais Livres/farmacologia , Fenóis/farmacologia , Plantas Medicinais/química , Polímeros/farmacologia , Antocianinas/química , Antocianinas/isolamento & purificação , Antibacterianos , Fármacos Anti-HIV/farmacologia , Bactérias/efeitos dos fármacos , Euphorbiaceae/química , Hemólise/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Testes de Sensibilidade Microbiana , Peru , Simplexvirus/efeitos dos fármacosRESUMO
Forty six aqueous extracts from 38 medicinal plant species belonging to different families were selected on the basis of their traditional medicinal use as antidiarrhoeic agents. They were submitted in a broad biological screening including antibacterial, antiamoebic and antispasmodic activities. The results of the testing have indicated that 37 extracts (80.43%), 33 (71.74%) and 32 (69.54%) exhibited some level of antibacterial, antiamoebic and antispasmodic activity respectively. Only 8 plant extracts (17.39%) would act as antidiarrhoeic agents by a triple pronounced antibacterial, antiamoebic and antispasmodic action. They include aqueous extracts from Euphorbia hirta whole plant, leaves of Psidium guajava and Tithonia diversifolia, root bark of Alchornea cordifolia, Heinsia pulchella, Paropsia brazzeana, Rauwolfia obscura and Voacanga africana.
Assuntos
Antidiarreicos/isolamento & purificação , Amebicidas/farmacologia , Animais , Antibacterianos/farmacologia , Antidiarreicos/farmacologia , Bactérias/efeitos dos fármacos , República Democrática do Congo , Entamoeba histolytica/efeitos dos fármacos , Feminino , Cobaias , Íleo/efeitos dos fármacos , Técnicas In Vitro , Masculino , Músculo Liso/efeitos dos fármacos , Parassimpatolíticos/farmacologia , Epiderme Vegetal/química , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Folhas de Planta/química , Raízes de Plantas/química , Plantas Medicinais/químicaRESUMO
Fractionation of the n-hexane extract of the leaves of Harrisonia abyssinica, collected in Guinea, afforded three novel and unusual prenylated polyketides, which were named oumarone (1), bissaone (2), and aissatone (3). Their structures were elucidated by spectroscopic methods, mainly 1D and 2D NMR spectroscopy.
RESUMO
Twenty extracts including ten EtOH and ten CH2Cl2 from different parts of nine African medicinal plants used in Congolese traditional medicine for the treatment of malaria, were submitted to a pharmacological test in order to evaluate their effect on P. falciparum growth in vitro. Of these plant species, 14 (70%) extracts including EtOH and CH2Cl2 from Cassia occidentalis leaves, Cryptolepis sanguinolenta root bark, Euphorbia hirta whole plant, Garcinia kola stem bark and seeds, Morinda lucida leaves and Phyllanthus niruri whole plant produced more than 60% inhibition of the parasite growth in vitro at a test concentration of 6 microg/ml. Extracts from E. hirta, C. sanguinolenta and M. morindoides showed a significant chemosuppression of parasitaemia in mice infected with P. berghei berghei at orally given doses of 100-400 mg/kg per day.
Assuntos
Antimaláricos/uso terapêutico , Malária/tratamento farmacológico , Extratos Vegetais/uso terapêutico , Plantas Medicinais/química , Plasmodium falciparum/efeitos dos fármacos , Animais , República Democrática do Congo , Feminino , Humanos , Técnicas In Vitro , Masculino , Medicina Tradicional , Camundongos , SolubilidadeRESUMO
Ten new acylated triterpenoid saponins were isolated from the leaves of Maesa lanceolata. For their structure elucidation extensive use was made of homo- and heteronuclear 2D NMR techniques such as COSY, NOESY, HSQC and HMBC. All saponins identified contained the same tetraglycosidic side chain, but the triterpenoid moiety showed a variable esterification pattern. Monoester, diester and triester derivatives were present. Maesasaponin I was a 21-monoester derivative, i.e. ¿3 beta-O-[alpha-L-rhamnopyranosyl-(1-->2)-beta-D-galactopyranosyl- (1-->3)]-[beta-D-galactopyranosyl-(1-->2)]-beta-D-glucuronopyranosyl+ ++¿-21 beta-angeloyloxy-13 beta, 28-oxidoolean-16 alpha, 22 alpha, 28 alpha-triol. Maesasaponins III, IV3, V3 and VI2 had an additional acetyl, propanoyl, n-butanoyl and angeloyl substituent, respectively, in position 22. Maesasaponins II, IV2, V2, VI3 and VII1 were characterised as the 16-acetyl derivatives of maesasaponins I, III, IV3, V3 and VI2, respectively. Structures of saponins previously reported in M. lanceolata had to be revised.