Effect of Cinnamon (Cinnamomum cassia) as a Lipid Lowering Agent on Hypercholesterolemic Rats

Background: Dyslipidemia is one of the important causes of cardiovascular disease related mortality and morbidity. Recently it has become a significant issue in public health problem of developing countries. The purpose of the study was to find a suitable solution for reducing blood lipid in dyslipidemic patients by conducting a research on the effect of cinnamon in hypercholesterolemic rats. Objective: To study the lipid lowering effect of Cinnamomum cassia on experimentally induced hypercholesterolemic rats. Materials and Methods: This study was done on 30 male Long Evans rats weighing about 200--210 gram. For convenience, the study was divided into two experiments --Experiment I and Experiment II. In experiment I, 12 animals were divided into two groups. One was Group A (n = 6, control group) fed on laboratory diet and the other was Group B (n = 6) fed on laboratory diet and cinnamon for 35 days. In experiment II, the remaining 18 rats were fed fatty mixture diet containing 1% cholesterol and 0.25% cholic acid. The hypercholesterolemic rats were then divided into 3 groups, Group C, D, and E (n=6 in each group). Group D and Group E were additionally fed on cinnamon powder and tablet atorvastatin for 35 days respectively. Serum TC, TG, LDL-C and HDL-C were measured after 35 days. Results: Fatty mixture diet increased TG, TC and LDL-C significantly. Cinnamon treated fatty mixture diet group showed that Cinnamomum cassia decreased plasma TC, TG and LDL-C. Atorvastatin therapy decreased TC, TG and LDL-C levels significantly compared with the lowering effect of cinnamon. Conclusion: The results of this experimental study indicate that Cinnamomum cassia can act as a hypocholesterolemic agent and thereby can improve cardiovascular functions.


Effect of Cinnamon (Cinnamomum cassia) as a Lipid Lowering Agent on Hypercholesterolemic Rats
Recently, hypercholesterolemia has been associated with enhanced oxidative stress related to increased lipid peroxidation. Increased generation of oxidized LDL is a major factor in the vascular damage associated with high cholesterol levels. Hence, the inhibition of oxidative stress under hypercholesterolemic conditions is considered to be an important therapeutic approach and efforts have been made to identify the antioxidative functions of various medicinal plants. 1 The use of plant extracts in managing various disorders is currently a common practice. Many plant materials are also in current use as supplements. Sometimes the aim is to lower the levels of some markers of disease states in order to improve health conditions. An example may be found in the use of substances that lower the cholesterol level in the system. Many studies indicate that lowering the serum cholesterol may prevent, control and even reverse artherosclerosis and coronary heart disease. Low triacylglycerol and low-density lipoprotein cholesterol (LDL-C) levels or high density lipoprotein cholesterol (HDL-C) levels are desirable health outcomes known to have resulted from the use of some plant materials. 2 Cinnamon is a plant that has a variety of uses among many different cultures, from spicing up foods to deterring germs from growing. There are actually two main forms of cinnamon that are commonly found in foods. The first, Cinnamomum verum, also known as "true" c i nnamon or ceylon cinnamon, is commonly used in sweet pastries. On the other hand, Cinnamomum cassia, also known as cassia, Chinese cinnamon or "bastard" cinnamon, is used as a stronger spice in a variety of foods. In fact, it is cassia-based cinnamon that is often seen on the grocery shelves and is most often cheaper than true cinnamon. 3 Cinnamate, a phenolic compound found in the inner bark of cinnamon lowers cholesterol level in high fat fed rats by inhibiting hepatic HMG Co-A reductase activity. 4 Polyphenolic polymers found in cinnamon have antioxidant activity and have been shown to reduce oxidative stress in dose dependent manner through inhibition of 5-lipoxygenase enzyme. 5 Cinnamon has a long history of use as spice and flavoring agent. Indeed, there are reports of cinnamon being imported to Egypt from China as early as 2000 BC. Cinnamon is mentioned in Chinese text written 400 years ago as well as in the Bible. 6 The aim of this study was to find a suitable solution for the hypercholesterolemic patients by conducting a research of cinnamon's effect on rats.

Materials and Methods
This experimental study was carried out in the department of Pharmacology and Therapeutics in Sir Salimullah Medical College and Bangladesh Centre for Scientific and Industrial Research (BCSIR) from July 2011 to June 2012.

Preparation of the cinnamon powder
Cinnamon powder was obtained from cinnamon bark which contained cinnamonaldehyde. The cinnamon powder was produced by crushing sun-dried cinnamon bark in a grinder machine.

Chemicals
Cholesterol and cholic acid (manufactured by Loba Chemic) and atorvastatin (manufactured by Beximco Pharmaceuticals) were purchased from the local market in Dhaka. A mixture of cholesterol, cholic acid and standard laboratory diet for rats had been administered to each rat per day for 35 days. 4

Animals
The study was performed on total number of 30 healthy adult Long Evans (Rattus Rattus) rats weighing between 200 to 210 gm collected from the BCSIR laboratory. The chosen animals were housed in cages separately at normal atmospheric temperature between 26 to 29 0 C under good ventilation and were given water and standard balanced diet. Animals were randomly distributed into five groups of six animals in each. Each cage was labeled for identification of different groups.

Experiment I
Experiment I was conducted to demonstrate the effect of Cinnamomum cassia on normal adult male rats. For this purpose a total number of 12 rats were taken and was divided into two groups containing six animals in each group.
Group A: Each animal received laboratory diet 20 gm/day and distilled water for 35 days.

Collection of blood specimens
The rats were kept fasted overnight before taking the blood samples. All the animals were anesthetized with diethyl ether and sacrificed. Blood samples were collected in test tubes and allowed to coagulate at room temperature. It was then centrifuged at 3000 rpm for 30 minutes in a centrifuge machine. The clear nonhemolysed supernatant sera was quickly removed and stored at --20ºC for biochemical analysis of serum lipid profile at the Biochemistry department of Sir Salimullah Medical College.

Biochemical Analysis
After collection of all blood specimens, serum total cholesterol (TC), serum high density lipoprotein cholesterol (HDL-C) and serum triglycerides (TG) were measured by enzymatic colorimetric (CHOD-PAP) method. Low density lipoprotein cholesterol (LDL-C) was calculated by Friedewald's formula.

Statistical analysis
The data were analyzed using unpaired t test.
Results were expressed as mean ± SE and P values <0.05 and <0.01 were considered statistically significant and highly significant respectively.

Results
Experiment I: Table I shows the effect of cinnamon on serum lipid profile of adult male rats. Serum total cholesterol, serum LDL cholesterol, HDL cholesterol and serum triglyceride levels did not show any significant difference between the Cinnamomum cassia treated group (Group B) and the control group (Group A). Experiment II: Table II shows the effect of fatty mixture feeding on serum lipid profile of adult male rats. Serum total cholesterol, serum LDL c h olesterol, and serum triglyceride levels showed significant difference between the fatty mixture diet group (Group C) and the control group (Group A). But there was no change in serum HDL-C level. Table III shows the effect of cinnamon on serum lipid profile of adult male rats fed with fatty mixture diet. Serum total cholesterol, serum LDL cholesterol, and serum triglyceride levels decreased significantly in Group D compared to Group C. But there was no change in serum HDL level.    In this study administration of atorvastatin at 0.2 mg/kg body weight for 35 days decreased serum cholesterol, TG, LDL-C approximately by 38%, 28% and 54% respectively of fatty mixture diet fed rats. HDL-C level was not changed significantly. These findings support study of Amin et al. 4 Cinnamon might have a direct role in lipid metabolism and prevent hypercholesterolemia and hypertriglyceridemia and lower free fatty acids by its strong lipolytic activity. Dietary cinnamate inhibits the hepatic HMG Co-A reductase activity resulting in lower hepatic cholesterol content and suppresses lipid peroxidation via enhancement of hepatic antioxidant enzyme activity. 12 Cinnamomum cassia may have an effect on treating hyperlipidemia and thereby may be responsible for the prevention of consequences of the aging process, from hypertension to heart failure, cardiovascular diseases and myocardial infarction. Therefore, further studies could establish the effect of Cinnamomum cassia o n h y perlipidemic human beings.
From the findings of the present study, it can be concluded that Cinnamomum cassia h a s hypolipidemic effect on hypercholesterolemic rats under different experimental conditions. Before establishing Cinnamomum cassia as a therapeutically effective hypolipidemic agent, further studies should be carried out to determine the active principle responsible for hypolipidemic effect and its cellular mechanism of action.