O Gabriel, N Harrision, O Okey, A Ukoha
blood dyscrasia, extract, hypolipidaemia, rats
O Gabriel, N Harrision, O Okey, A Ukoha. Changes In Lipid And Haematological Profile Of Aqueous Ethanolic Extract Of Alstonia Boonei In Rats. The Internet Journal of Hematology. 2007 Volume 4 Number 1.
This study investigated the effect of 50 and 200mg/kg extract of
Phytochemical studies identified the principal constituents to be indole alkaloids from which echitamine, alstonine, alstonidine, amyrin, lupenol, porphyrine, triterpines and ursane have been isolated. Extracts of
Pharmacological screenings have been carried out on some constituents of the plant extract. The anti-inflammatory activity has been widely reported in different animal models. Ojewole, (1984) Raji
However, cardiovascular diseases present some of the main health problems across the globe today, the major ones being coronary heart diseases, stroke and hypertension (Alters & Shiff, 1997). Elevated plasma lipids are risk factors in cardiovascular problems. Hyperlipidaemia and other abnormal blood lipid profile are largely of genetic origin or due to unwholesome nutritional habits. Lipids and other substances accumulate on arterial wall, forming plague, which occlude the vascular lumen and obstruct the blood flow to vital organs such as the heart, brain, liver, or kidney. Obstruction of blood supply to the heart, brain, liver or kidney cause coronary heart diseases, stroke or kidney failure, as the case may be.
The important lipids whose elevations are implicated in these disease conditions are cholesterol and triacylglycerols. Lipids are transported as lipid-protein complexes called lipoprotiens, which are classified based on their density and charges. The high-density lipoprotein cholesterol (HDL-c) transports lipids out of blood cells to the liver, while the low density lipoproteins cholesterol (LDL-c) mobilizes lipids against the cells and blood vessels. Triacylglycerols have been found to be elevated along with total cholesterol elevation. Therefore, elevated low-density cholesterol, triacylglycerols and total cholesterol with reduced HDL-c will enhance the development of atherosclerosis and related cerebrovascular disorders (Nwanjo, 2004). The clinical consequences of these disease conditions are serious; and meaningful research efforts to improve the knowledge and understanding of the pathogenesis is essential; in order to provide a more rational approach to their prophylaxis and treatment.(Kritchersky,1970; kucera
The blood is a vital fluid, which contains the Red Blood Cell (RBC), White blood cells (WBC) and platelets suspended in the serum in homeostatic concentrations. The circulatory blood volume makes up about 8% of the weight of an average man. The blood cells take up about 45% of the blood, while plasma constitutes about 55%(Guyton & Hall, 2000).
The Blood is important for pulmonary and tissue respiration, as a medium of endocrine and neurohumoral transmissions, biotransformation and metabolic excretion (Adebayo
Despite the several studies on the different pharmacological activities of
Materials And Methods
The stem bark of
Preparation of Plant Extract
The shaded stem bark was cut into pieces and dried in an oven (Grant instruments, Cambridge, England) at 50 0 C to constant weight (2.60kg approx). It was ground using a Thomas Contact Mill (Pye Unicam, Cambridge, England). 500g of the powdered stem bark were soaked in 7.75 L of 70% ethanol (BDH) for 24 hours in a soxhlet extractor. The resulting aqueous ethanolic extract was concentrated using a rotatory evaporator (Laborato 400, China). A 16.0g residue was obtained and stored in a refrigerator (4 0 C). Appropriate measures and dilutions of the residue were made with normal saline (using Metler analytical weighing balance, 0.DPI-200g) to obtain the required doses.
Acute Toxicity Test
The acute toxicity of the extract was done using 30 albino rats divided into 5 groups of 6 rat each, with each group receiving a dose of the extract intraperitonally (i.p.) as described by Miller and Tainter (1994). The number of death in each group within 24 hours was recorded. The lethal dose-50 (LD50) was estimated from the graph of percentage mortality (converted to probit) against log-dose of the extract; probit 5 being 50%.
Thirty albino rats (200-350g) of both sexes were obtained from the Animal House of the College of Medicine and Health Sciences, Imo state University, Owerri. The animals were haboured in stainless steel cages under standard laboratory condition of 12 hours light /dark cycle. They had access to feed (Top Fed, Sapele) and water
The thirty rats were randomly assigned to 6 experiment groups of 5 rats each. In addition to feed and water;
The extracts were also given by oral tubation.
By the end of each experimental period, the rats were reweighed, starved for 24 hours and sacrificed under chloroform anaesthesia.5ml of blood was collected from each animal by cardiac puncture using sterile needle and syringe. Part of the blood sample was put into test tubes and allowed to clot for 30 minutes before centrifuging at 800g (Wisperfuge, 1384, Samson, Holland) for 5 minutes. The supernatant was used for the lipid analysis. The remaining blood sample was put in an EDTA bottles for haematological determinations.
The serum total and HDL-cholesterol were estimated by the method of Lopez –Vitrella
The haemoglobin (Hb) level was measured by the cyanomethaemoglobin method. The Red Blood Cell (RBC) and Reticulocyte counts were determined by visual method (Baker and Siverton, 2000). Packed cell volume (PCV) was measured using microheamatocrit method and total White Blood Cell (WBC) count was estimated by visual method (Cheesbrough 2000). The RBC indices were calculated from the RBC count, Hb level and PCV estimations (Baker and Siverton 2000, Cheesbrough, 2000).
The results were analyzed using Duncan multiple range test. All data were expressed as mean ± SD. Differences between groups were considered at 95% confidence limit and probability level of 0.05. Probability < 0.05 was taken as significant.
The serum triacylglcerols level was significantly reduced at 50mg/kg and 200mg/kg after the second week. The changes after the second week were marginal decreases (Table 3). The ratio of the atherogenic risk predictor indices showed that the extract may posses antiatherogenic effect and therefore desirable. The haematological parameters were not affected by the plant extract, except for WBC where the fall was significant (p < 0.05) at 200mg/kg by the 4 th week treatment.
Atherogenicity with subsequent cardiovascular manifestations is one of the major causes of death and morbidity in the world (Raju and Binda, 2005). Various studies indicate that high serum cholesterol levels are strongly related to coronary atherosclerosis and increased risk of cardiovascular diseases. Clinical studies have also shown that lowering levels of serum cholesterol using diet or drugs decreases the incidence of coronary heart disease (Steiner & Li, 2000, Treasure,
Increased LDL cholesterol with decreased HDL cholesterol usually increases the serum total cholesterol. This is because the plasma clearance of cholesterol is often impaired in the presence of low HDL –C. Triacyglycerols levels have also been found to increase with increase in plasma cholesterol. Atherogenicity therefore develops when LDL cholesterol, triacylglycerols and total cholesterol are elevated relative to plasma HDL-C. Elevated HDL-cholesterol improves the transportation of cholesterol from the plasma to the liver for biotransformation and excretion, thereby preventing atheroma formation and blood vessel occlusion (Ojiako and Nwanjo, 2005).
The administration of 50 and 200mg/kg
Echitamine, the major constituent of the plant extract has been reported to be responsible for most of the pharmacological activities observed in the plant extract. Echitamine is an alkaloid with antioxidative and free radical scavenging properties ( Elisabetsky & Costa- campos, 2006). Antioxidants prevent the oxidative modification of lipoproteins before their incorporation into the fatty streaks of the arterial wall. Studies have shown that oxidation of lipids increases their deposition on arterial walls, hence atherosclerosis and atherogenicity. However, the exact mechanism by which antioxidants lower blood cholesterol is not properly established. Galton & Krone (1991) suggested that it could be by promoting the stimulation of cholesterol excretion in the faeces via its biotransformation to bile acids.
The blood is the vital fluid that transports gases and nutrients to the tissues of the body. The biochemistry of the blood is directly linked to the functional capacity of the blood. The functional capacity of the blood is associated with the status of the blood components. And the health of the individual is affected by different disease conditions such as anemia, foreign bodies, including drugs and drug products, which find their way into the blood and other tissues.
The aqueous ethanolic extracts of Alstonia boonei are widely employed in traditional medicine practice where they are claimed to alleviate a wide range of ailments. Irrespective of their target organs, the extracts are conveyed to their sites of action via the blood stream. This makes it imperative to study the influence of this extract on blood parameters.
There were no significant changes (p>0.05) in the heamatological parameters except for WBC where the fall was significant (p<0.05) at 200mg/kg by the 4 th week of treatment. Costa-campos,
It is concluded that
Gabriel Oze, College of Medicine, Imo State University, Owerri.