Efficacy of Zanthoxylum armatum fruit on isoproterenol induced myocardial infarction in rats

a Department of Biochemistry, PSG College of Arts & Science, Coimbatore641014, Tamilnadu, India. b Department and Graduate Institute of Applied Chemistry, Chaoyang University of Technology, No.16, Jifeng East Road, Wufeng District, Taichung City – 41349, Taiwan (R.O.C). c Raman Research Laboratory, PG & Research Department of Physics, Government Arts College, Tiruvannamalai-606603, Tamilnadu, India d Department of Chemistry, Sri Vijay Vidyalaya College of Arts and Science (Women’s college), Dharmapuri, Periyar University, Tamilnadu, India. e PG & Research Department of Chemistry, Government Arts College, Tiruvannamalai-606603, Tamilnadu, India


Introduction
Cardiovascular disease (CVD) is the first leading cause of death worldwide, claiming about 17.1 million lives a year. In India particularly in urban areas 31.7 % of deaths occur due to MI [1]. It is mainly due to the changes in lifestyle. In 1970 the incident of CVD was only about 7% and was increased up to 39% in 2017. MI is a key component of the trouble of CVD which is associated with complications and mortality [2]. The chronic development of atherosclerotic lesions in MI is due to elevated serum levels of myocardial markers such as CK-MB, AST and LDH including troponin -T [3,4]. High levels of serum total cholesterol (TC), low density lipoprotein (LDL), triglycerides (TG) and decreased levels of high density lipoprotein (HDL) are correlated positively in the coronary atherosclerosis [5].
Pharmacological induction of MI by subcutaneous administration of ISO in rats is a well standardized and frequent representation to study the defensive property of many drugs and cardiac function [6]. It is a synthetic catecholamine and β-adrenergic agonist induces severe stress in the myocardium resulting in the necrosis of the heart muscle. It has been proposed by various mechanisms and one of it includes the production of toxic free radicals through the auto oxidation of catecholamine [7].
Many modern drugs are effective in the treatment of CVD, but their application is limited because of their side effects. Recently, there has been an upsurge of interest to search the cardioprotective potential of natural foodstuffs [8]. At present, natural products and medicinal plants have gained much attention as possible source of antioxidants due to their excellent efficiency in opposition to reactive oxygen species (ROS) stimulate pathologies [9].
Z. armatum is an important medicinal plant extensively used locally for curing several diseases. Though ancient literature states the use of this extract for CVD, there is lack of scientific information regarding the effect of Z. armatum fruit. In our previous study, Z. armatum fruit was characterized for its phytoconstituents and antioxidants. However, the pharmacological exploitation of this fruit has been rarely reported and hence the fruits of Z. armatum were evaluated on the cardiac changes associated with ISO induced MI for its cardioprotective activity.

Induction of MI
ISO hydrochloride was used to induce MI in rats.
Animals were injected subcutaneously with freshly prepared ISO hydrochloride in sterile normal saline at a dose of 8.5mg/100g body weight.

Experimental design
Animals were divided into six groups of six rats in

Biochemical estimations in serum
The activities of AST, ALT and LDH were estimated by the standard methods [10,11]. CK-MB was assayed using commercial kit obtained from Agappe lipoprotein-cholesterol (LDL-c) and very low-density lipoprotein cholesterol (VLDL-c) were determined by using Fridwald's formula [12].

Preparation of tissue homogenate
One gram of heart tissue was taken and homogenized with 0.1M cold tris buffer (pH 7.4) in a potter homogenizer fitted with Teflon plunger at 600 revolutions per minute for 3 minutes. The homogenate was taken for the analysis of various biochemical parameters. were assayed by using standard methods [18][19][20].

Statistical analysis
Statistical analysis was performed using one way analysis of variance (ANOVA) followed by Duncan's Multiple Range Test (DMRT) using SPSS Software Package version 12.00. Results were expressed as mean ± SD (standard deviation) from six rats in each group. P<0.05 were considered to be significant.

Results and Discussion
In the present study, table 1

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Furthermore, the level of diagnostic markers CK-MB, LDH and troponin T were increased in ISO-treated rats that indicates myocardial damage and our finding was in consonance with an earlier report. Troponin -T has been shown to be highly sensitive and specific marker of myocardial injury. Increased serum marker activities might be due to enhanced susceptibility of myocardial membrane to the ISO mediated peroxidative damage resulting in increased release of these enzymes into the blood stream [25].

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It also lowers the HDL-C and enhances the LDL-C levels in the circulation that results in the arterial deposition. ISO further promotes the degradation of lipids [27]. Table -3    important not only because they react with free radicals directly but also they act synergistically with one another [34]. GSH is an intracellular thiol that participates directly in the destruction of H2O2. Depletion of mitochondrial GSH is a major mechanism for inducing an imbalance in the mitochondrial function. ISO reduce glutathione levels, leading to the loss of membrane integrity, myocytotoxicity and finally producing myocardial necrosis. The decreased activity of GPx observed in ISO induced rats is due to the reduced availability of the substrate GSH [35].

Conclusion
In conclusion, the hydroethanolic extract of Z.
armatum fruit can be considered as a good protector against ISO induced toxicity in rats which prevent the myocardium of rat heart from oxidative damage due to its non-toxicity profile, acceptable route of administration (oral) and boosting the antioxidant capacity. Further characterization and purification of the bioactive compounds would be necessary to determine the exact mechanism of action of Z. armatum fruit.