Cardioprotective and anti-atherosclerotic effects of Rhamnus prinoides extracts in animal models

Rhamnus prinoides (R. prinoides) are small trees or shrubs which are rigid and branched. Its barks and roots are used for treatment of various ailments and diverse diseases. It is commonly distributed in rift valley and central provinces of Kenya. A little is known about its safety and antihyperlipidemic effects in management of atherosclerosis. 10% DMSO and normal saline was used to reconstitute the R. prinoides extracts because of its stability and reliable solvent for extraction in organic and inorganic application. Mature Albino Wistar rats three months old were fed with HCHF diet (10% egg York (5.6g/bw),10% lard (5.6g/bw),0.2% cholic acid (0.112g/bw) and 0.59% propylthiouracil (0.28g/bw), for 28 days. Onset of 28th day, the rats were euthanized and bioassays done. Both body weights and organ weights were recorded. For cardiotonic studies, 5 New Zealand male rabbits were used. They were injected with 1000 units of heparin to avoid clot formation. Chest was opened through cardiac thoracotomy and heart placed in a dish containing Tyrode solution. Langerdorff method was used using a kymograph in the study of ionotropic and chronotropic effects. In toxicity studies, male mice of age 6-7 weeks were given oral doses of plant extract inclusive of the control for 28 days of the experiment. On 29th day of the experiment, animals were sacrificed through cardiac puncture and the blood sample collected was used for hematological and biochemical assays. Mice were ruminated with rodent pellets and water without cease. OECD 407 precepts were followed when conducting toxicity studies. One way ANOVA was used in data analysis. This was followed by Tukey as post hoc and statistical significance at p<0.05. Extracts of R. prinoides showed presence of saponins, alkaloids, glycosides, terpenoids, steroids and phenolics. R. prinoides plant extracts exhibited positive ionotropic and negative chronotropic effects. Significance reduction on low density lipoproteins and total cholesterol was exhibited by R. prinoides plant extracts, following a high cholesterol high fat diet.