Study on in Vitro Cholesterol Esterase Inhibitory Activity and in Vivo Antihyperlipidemic Activity of Anisomeles Malabarica Leaf Extract

Anandhi, B (2017) Study on in Vitro Cholesterol Esterase Inhibitory Activity and in Vivo Antihyperlipidemic Activity of Anisomeles Malabarica Leaf Extract. Masters thesis, Sri Ramakrishna Institute of Paramedical Sciences, Coimbatore.


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INTRODUCTION: CHOLESTEROL:Cholesterol is a waxy, fat-like substance that’s found in all cells of the body. All of them have a similar cyclic nucleus resembles the phenanthrene rings (rings A, B, C) to which a cyclopentanone ring is attached. The parent nucleus is better designated as cyclopentano perhydrophenanthrene. They are divided as sterols, bile acids, sex hormones, etc., Our body needs some cholesterol to make hormones, vitamin D, and substances that help us to digest foods. Quantity of cholesterol will be 140 gms in the body of a man weighing 70 kg. Greater part of the cholesterol in the body is synthesized whereas 0.3 gram per day is provided by the average diet. Normal concentration of cholesterol in the blood is 140-220 mg per 100 ml of blood. Cholesterol travels through the bloodstream in small packages called lipoproteins.Two kinds of lipoproteins carry cholesterol throughout our body: lowdensity lipoproteins (LDL) and high-density lipoproteins (HDL). Having healthy levels of both types of lipoproteins is important. LDL cholesterol is called “bad” cholesterol. A high LDL level leads to a build up of cholesterol in the arteries. HDL cholesterol is called “good” cholesterol. This is because it carries cholesterol from other parts of the body back to the liver, which removes the cholesterol from our body. OBJECTIVE OF THE STUDY:Hyperlipidemia is a heterogeneous disorder characterized by an elevation in total cholesterol (TC), triglycerides (TG), very low density lipoprotein cholesterol (VLDL-C), low-density lipoprotein cholesterol (LDL-C), free fatty acids (FFA), and apolipoprotein B (apo B) levels, as well as reduced high-density lipoprotein cholesterol (HDL-C) levels. These disorders happen as a result of either metabolic disorders or dietary and lifestyle habits. Several studies have revealed that an decrease in HDL-C and increase in TC, LDL-C and TG are associated with an increase in the risk of ischemic heart diseases. Many drugs have been reported to possess hypolipidemic activity like bile acid binding resins, statins, fibrates, niacin and cholesterol absorption inhibitors which are the common treatment for hyperlipidemia. However, severe side effects are associated with the use of these drug for lipid-lowering medications.(3) Many natural compounds were reported as hypolipidemic agents such as polyphenolics, flavonoids, tannins, alkaloids, phytosterol, unsaturated fatty acids and dietary fibers.(7) The main objective of this study was to evaluate the in vitro cholesterol esterase inhibitory activity and in vivo antihyperlipidemic activity of Anisomeles malabarica leaf extract. DISCUSSION AND CONCLUSION: Hypercholesterolemia and the resulting atherosclerosis have been implicated in the pathophysiology of coronary heart diseases and myocardial ischemia. Lowering cholesterol level may decrease the risk of CVD, and therefore enormous efforts have been extended to achieve this aim. The hypocholesterolemic activity of ethanolic leaf extract of Anisomeles malbarica (AMLE) against hypercholesterolemia was monitored on the Lipid profile status, antioxidant status, activities of serum cardiac marker enzyme, and histological changes of liver and heart. In this study the high cholesterol diet (HCD) is used which consists of maize, soya meal, coconut cake, rice polish, groundnut cake and animal fat such as tallow which has been used in inducing experimental hypercholesterolemia.(46) In the current study, the HCD fed rats showed increased levels of plasma cholesterol (TC), and triglycerides (TG) levels compared to normal control rats. Treatment with AMLE significantly decreased the levels of serum TC, TG, when compared to HCD induced rats. Saponins are also reported to precipitate cholesterol from micelles and interfere with enterohepatic circulation of bile acids making it unavailable for intestinal absorption, this forces liver to produce more bile from cholesterol and hence the reduction in serum cholesterol level. Saponins are also reported to lower triglycerides by inhibiting pancreatic lipoprotein lipase. Similarly in our study also, the presence of both flavanoids and saponins in AMLE could have contributed in reducing the levels of lipid status (TC, TG,) elevated levels of serum low density lipoprotein cholesterol (LDL) and very low density lipoprotein cholesterol (VLDL) are often accompanied by premature atherosclerosis and other CVD. A low level of high-density lipoprotein cholesterol (HDL) is also an important risk factor for cardiovascular disease. The cardioprotective effects of HDL have been attributed to its role in reversing cholesterol transport, its effects on endothelial cells, and its antioxidant activity. Flavanoids can increase HDL-C and also decreases oxidation of LDLcholesterol. High cholesterol diet increases serum LDL levels and oxidative stress which results in the production of increased oxidized LDL and thereby increases atherosclerotic plaque formation. From our present study it is evident that HCD induced rats showed increased serum LDL and VLDL levels with the concomitant reduction in serum HDL level, when compared to normal rats. Supplementation with AMLE reduced the serum LDL and VLDL levels and increased the serum HDL level which could be due to reduction in plasma total cholesterol and increasing LDL receptor activity by the flavanoids and phytosterol present in the plant extract. Also it could be presumed that the reduction of total cholesterol by AMLE could have been associated with a reduction of its LDL fraction, which is the target of several hypolipidemic drugs. Oxidative stress is believed to contribute to the pathogenesis of hypercholesterolemic atherosclerosis hence, various antioxidant compounds are being evaluated for potential antihypercholesterolemic effects. A high fat diet brings about remarkable modifications in the antioxidant defence mechanisms of rat tissues by the process of lipid peroxidation. Several reports have shown that hypercholesterolemia diminishes the antioxidant defence systems by producing free radicals and thereby elevating the lipid peroxide products, resulting in the production of toxic intermediates. Superoxide dismutase is the first enzyme in antioxidant defense that protects tissues against oxygen free radicals by catalyzing the removal of superoxide radical (O2 .-), which damages the membrane and biological structures.Catalase has been shown to be responsible for the detoxification of significant amounts of Hydrogen peroxide.(50) SOD and CAT are the two major scavenging enzymes that remove the toxic free radicals. From our study we observed that there was a reduction in the activity of hepatic SOD and CAT in HCD induced rats when compared to control rats , this may be due to the enhanced production of Reactive Oxygen Species (ROS) by HCD. This free radical affects the antioxidant activity and hence resulted in the decreased activity of SOD and CAT.

Item Type: Thesis (Masters)
Additional Information: REG.No. 261525101
Uncontrolled Keywords: Vitro Cholesterol Esterase Inhibitory Activity ; in Vivo Antihyperlipidemic Activity ; Anisomeles Malabarica Leaf Extract
Subjects: PHARMACY > Pharmacology
Depositing User: Ravindran C
Date Deposited: 21 Mar 2018 06:19
Last Modified: 21 Mar 2018 06:19

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