RESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Heinsia crinita is used in traditional medicine for the treatment of febrile illness and erectile dysfunction. Its stem bark powder is found in some peripheral markets in the Democratic Republic of the Congo (DRC) as a remedy against malaria. Investigations were conducted on crude extracts of leaves, fruits and stem barks in view to validate their use and to determine which plant part possesses the best antiplasmodial properties. MATERIALS AND METHODS: Different plant parts were extracted with methanol, ethanol and dichloromethane. Based on the preliminary assays, the dichloromethane extract of the stem bark was subjected to fractionation using preparative HPLC system and column chromatography. This step led to the isolation of two new iridoids which had their structures elucidated by NMR, UV, MS and FT-IR spectroscopic techniques. Extracts and pure compounds were tested in vitro against the 3D7 strain of Plasmodium falciparum. The inhibition of the parasite growth was evaluated in vitro by colorimetric method (p-LDH assay) and their cytotoxicity evaluated in vitro against the human non-cancer fibroblast cell line (WI38) through WST1 assay. The in vivo antiplasmodial activity was assessed by the inhibition of Plasmodium berghei growth in infected mice treated with the ethanol extract of H. crinita stem bark at the concentrations of 200 and 300mg/Kg/day per os, using a protocol based on the 4-d suppressive test of Peters and compared to a non-treated negative control group of mice (growth =100%). Finally the antioxidant activity of the same extract was evaluated using ABTS, DPPH and cell-based assays. RESULTS: A moderate in vitro antiplasmodial activity was observed for the dichloromethane extract of the stem bark of H. crinita (IC50 =29.2±1.39µg/mL) and for the two new iridoids, lamalbide 6, 7, 8- triacetate (IC50 =16.39±0.43µg/mL) as well as for its aglycone lamiridosin 6, 7, 8-triacetate (IC50 =0.44.56±1.12µg/mL). The ethanolic stem bark extract (200 and 300mg/kg/day, oral route) showed a moderate in vivo antimalarial activity in Plasmodium berghei-infected mice with 27.84±2.75% and 48.54±3.76% of inhibition of the parasite growth, respectively (p<0.01).). This extract displayed high cellular antioxidant activity using dichlorofluorescein-diacetate (DCFDA) on HL-60 monocytes. These crude extracts and pure compounds tested at the higher concentration of 100µg/mL did not show any cytotoxicity against WI38 cells. CONCLUSIONS: The results showed that H. crinita extracts possess antimalarial activity and contain some unusual iridoids with moderate antiplasmodial activity, therefore justifying to some extent its traditional use by the local population in DRC for this purpose. This is the first report of the isolation and antiplasmodial activity of these two new iridoids.
Assuntos
Antimaláricos , Iridoides , Malária/tratamento farmacológico , Extratos Vegetais , Rubiaceae , Animais , Antimaláricos/análise , Antimaláricos/farmacologia , Antimaláricos/uso terapêutico , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Feminino , Frutas , Células HL-60 , Humanos , Iridoides/análise , Iridoides/farmacologia , Iridoides/uso terapêutico , Malária/parasitologia , Camundongos , Casca de Planta , Extratos Vegetais/análise , Extratos Vegetais/farmacologia , Extratos Vegetais/uso terapêutico , Folhas de Planta , Plasmodium berghei/efeitos dos fármacos , Plasmodium berghei/crescimento & desenvolvimento , Plasmodium falciparum/efeitos dos fármacos , Plasmodium falciparum/crescimento & desenvolvimento , Espécies Reativas de Oxigênio/metabolismoRESUMO
African populations use traditional medicines in their initial attempt to treat a range of diseases. Nevertheless, accurate knowledge of the composition of these drugs remains a challenge in terms of ensuring the health of population and in order to advance towards improved traditional medicines (ITMs). In this paper chromatographic methods were developed for qualitative and quantitative analyses of a per os antimalarial ITM containing Garcinia kola. The identified analytical markers were used to establish TLC and HPLC fingerprints. G. kola seeds were analysed by HPLC to confirm the identity of the extract used by the Congolese manufacturer in the ITM. The main compounds (GB1, GB2, GB-1a and Kolaflavanone) were isolated by preparative TLC and identified by UPLC-MS and NMR. For the quantification of the major compound GB1, a simple and rapid experimental design was applied to develop an LC method, and then its validation was demonstrated using the total error strategy with the accuracy profile as a decision tool. The accurate results were observed within 0.14-0.45mg/mL range of GB1 expressed as naringenin. The extracts used in several batches of the analysed oral solutions contained GB1 (expressed as naringenin) within 2.04-2.43%. Both the fingerprints and the validated LC-DAD were found suitable for the quality control of G. kola-based raw material and finished products, respectively.
Assuntos
Antimaláricos/análise , Biflavonoides/análise , Cromatografia Líquida de Alta Pressão/métodos , Garcinia kola/química , Extratos Vegetais/química , Antimaláricos/isolamento & purificação , Biflavonoides/isolamento & purificação , Flavanonas/análise , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Sementes/químicaRESUMO
The present study was undertaken to investigate the cardiovascular effect of three extracts from the root bark of Anthocleista schweinfurthii Gilg.: an aqueous extract (AE), a dichloromethane extract (DCMR) and a fraction enriched in cardiac glycoside type compounds (CARDAN). In isolated perfused frog heart, bolus injection of the extracts produced a positive inotropic effect. The responses to AE and DCMR, but not to CARDAN, were depressed by propranolol. In isolated rat aorta, DCMR produced a transient increase in contractile tension while AE and CARDAN induced a sustained constriction. AE vasoconstrictor effect was abolished by phentolamine, while contraction evoked by CARDAN was antagonized by verapamil. In aortic rings contracted in low K+ media, the addition of K+ evoked a relaxation, which was abolished by ouabain, depressed by DCMR but not affected by either A(E) or CARDAN. These observations indicate that Anthocleista schweinfurthii contains substances that promote vasoconstriction and increase cardiac contraction. The effect of DCMR was only partially mediated by inhibition of the Na+ pump while the mechanism of action of A(E) and CARDAN was distinct from the inhibition of the Na+, K+ - ATPase pump, but could involve adrenergic receptors, or either direct or indirect activation of L-type calcium channels.