Fresh and Decayed Stem Juice of Musa acuminata x balbisiana (Musa paradisiaca) Reduce the Force and Rate of Contractility of an Isolated Perfused Rabbit Heart.

Background: Decaying stem juice of Musa acuminata × balbisiana is commonly used by local communities and traditional herbalist in Central Uganda in the management of cardiovascular conditions like hypertension. Aims: The study investigated the ionotropic and chronotropic effect of fresh and decaying stem juice of Musa acuminata × balbisiana on the isolated perfused rabbit heart. Materials and Methods: Methods. Study Design: An experimental study. Place and Duration of Study: Study was done at the Dept of Pharmacology & Therapeutics Pharmacology Lab between December 2012 to March 2013. Experimental Procedure: An experimental study determined the effects of fresh and decayed stem juices of Musa acuminate X balbisiana on the rate and force of contraction of an isolated rabbit heart using Langendorff’s heart perfusion experiment and methods. The heart rate (beats/minute) was determined. The force of contraction of the heart was determined by measuring the height of each peak on the kymogram. Results: The force and rate of contractility of an isolated perfused rabbit decreased with increasing doses of the stem juice from 0.156 mg/mL to 100mg/mL for both the fresh and decayed stem juice of M. acuminata. The decrease could be associated with the high [K+] ions that decrease the membrane potential or cause hyperpolarization the myocardial cell membranes leading to reduced force and rate of heart contractility. The effect of the fresh stem juice was short lived and at very high concentrations, it caused a cardiac arrest while the effect of the decayed stem juice was prolonged. Conclusion: Fresh and decayed stem juice of Musa acuminata × balbisiana have compounds that cause a negative ionotropic and chronotropic effect on an isolated perfused rabbit heart.

Plants traditionally used against malaria: phytochemical and pharmacological investigation of Momordica foetida

Leaves from Momordica foetida traditionally used to treat symptoms of malaria in parts of East Africa were studied for in vitro antimalarial activity. Using an [³H] hypoxanthine-incorporation assay the antiplasmodial activity of hydrophilic and lipophilic extracts against the chloroquine-sensitive strain poW and the multiresistant clone Dd2 of Plasmodium falciparum was determined. The petrol ether/ethyl acetate extract showed significant activity with IC50 values of 7.3 µg/mL (poW) and 13.0 µg/mL (Dd2). Cytotoxicity was estimated on two human cell lines HepG2 and ECV-304 and a selectivity index (SI) was calculated, ranging between 12 and 15. Phytochemical analysis led to the isolation of a number of phenolic glycosides, e.g. eriodictyol-, 5,7,4-trihydroxyflavanone-, kaempferol- and 5,7-dihydroxychromone-7-O-beta-D-glucopyranoside, not previously known from M. foetida. In order to prove one possible mode of action the influence of the crude extracts as well as the isolated compounds on the heme degradation with chloroquine as reference compound was evaluated. The ethyl acetate extract showed about 88 percent inhibition of heme degradation, quite similar to chloroquine (84 percent), and also eriodictyol-7-O-beta-D-glucopyranoside (2) inhibited heme degradation by 86 percent.

Folhas de Momordica foetida tradicionalmente usadas para tratar sintomas de malária em partes da Africa Oriental foram estudadas in vitro com respeito à sua atividade antimalárica. Utilizando-se o teste de incorporação de hipoxantina [³H] a atividade antiplasmódica dos extratos hidrofílico e lipofílico contra a cepa sensíveis a cloroquina poW e o clone multiresistente Dd2 de Plasmodium falciparum foi determinada. O extrato éter de petróleo/acetato de etila mostrou atividade significativa com valores de CI50 de 7,3 µg/mL (poW) e 13,0 µg/mL (Dd2). A citotoxicidade foi estimada em duas linhas de células humanas HepG2 e ECV-304 e o índice de seletividade (IS) foi calculado, variando entre 12 e 15. A análise fitoquímica levou ao isolamento de um número de glicosídeos fenólicos, por exemplo eriodictiol-, 5,7,4-triidroxiflavanona, kaempferol e 5,7-diidroxicromona-7-O-beta-D-glicopiranosideo, descritos pela primeira vez de M. foetida. Na tentativa de provar um possível modo de ação foi avaliada a influência dos extratos brutos bem como dos compostos isolados sobre a degradação da heme usando-se cloroquina como composto de referência. O extrato acetato de etila mostrou inibição da degradação da heme em torno de 88 por cento, bastante similar a cloroquina (84 por cento) e também o eriodictiol-7-O-beta-D-glicopiranosideo (2) inibiu a degradação da heme em 86 por cento.