Abstract

In 2008, the leading cause of mortality worldwide was cardiovascular (CV) disease, resulting in 17.3 million deaths, representing 30% of all global deaths. Myocardial infarction (MI) is a major cause of mortality and morbidity, often resulting as a complication of hypertension. Almost 40% of patients with ischaemic heart disease (IHD) who die suddenly have a history of hypertension (Law et al., 2003). Kalanchoe pinnata have been used in folk medicine as stomach pain relief, against gastritis, diarrhoea, bilharzias, dysmenorrhoea, liver disorders, fever, female infertility, genitourinary infections, snake and scorpion bites, leprosy, cough, asthma, kidney stones, arthritis, cardiovascular diseases and general tiredness (Hutchings et al., 1996; Van Wyk et al.,1997; Quazi Majaz et al., 2011).  The aim of the present study was to determine the effects of kalanchoe pinnata aqueous extract on some biochemical makers in salt loaded rats. 30 rats were randomly divided into 6 groups of 5 animals each. All the animals were administered NaCl (18%) except the neutral animals that received just tap water. groups 3, 4 and 5 received the aqueous extract of k. pinnata at increasing doses (50, 100, 150 mg/kg respectively) Groups 2, 3, 4 and 5 received Isoproterenol (150 mg/kg) subcutaneously for two days before sacrifice. During sacrifice, blood was collected through cardiac puncture and serum was separated. The levels of total cholesterol, Low Density Lipoprotein (LDL) and High-Density Lipoprotein (HDL) were determined in serum. The results obtained shows that the aqueous extract of Kalanchoe pinnata caused a significant reduction in the levels of total cholesterol and low density lipoproteins. This potential of Kalanchoe pinnata was due to the presence of total phenolic and flavonoids compounds. It was therefore concluded that Kalanchoe pinnata could be used to treat miocardiac infarction.

CHAPTER ONE

Introduction and literature review

1.1 Background to the study

In 2008, the leading cause of mortality worldwide was cardiovascular (CV) disease, resulting in 17.3 million deaths, representing 30% of all global deaths. Among these, an estimated 7.3 million were due to coronary artery disease and 6.2 million due to stroke (World Health Organization, 2011). Deaths attributed to CV disease are expected to further increase to 23.3 million by 2030 (Mathers and Loncar, 2006). Since the death rates attributed to CV disease are predicted to rise in the future,  it is important to focus on and improve our understanding of the reasons for high CV rates in our societies in order to counteract this growing problem.

Hypertension is a major public health issue, particularly in developing countries as a whole. It is now well established that over 80% of the burden of the disease is in low-income and middle-income regions (Lawes et al., 2001). It is predicted that by 2025, the prevalence of hypertension (HTN) will increase by 60% to a total of 1.56 billion worldwide (Kearney et al., 2005) suggesting that HTN remains a major public health problem. HTN in Sub-Saharan Africa (SSA) has also been on the rise with reports indicating higher values in urban settings compared to rural settings (Mufunda et al., 2006).

There are many studies on risk factors predisposing to hypertension.Obesity is a major risk Excess alcohol intake has been associated with increased blood pressure (Kloner et al., 2007). Other major risk factors for coronary artery disease are; high blood pressure, high cholesterol, smoking, and a sedentary lifestyle (Van De Graaff et al., 2002).

Myocardial infarction (MI) is a common presentation of ischemic heart disease. According to the World Health Organization, it will be the major cause of death in the world by the year 2020 (Lopez et al., 1998). Myocardial infarction (MI) is a major cause of mortality and morbidity, often resulting in a complication of hypertension. Almost 40% of patients with ischaemic heart disease (IHD) who die suddenly have a history of hypertension (Law et al., 2003).

Kalanchoe pinnata, also named Bryophyllum pinnatum, belongs to the family Crassulaceae whose species possess an array of medicinal effects. They are used in folk medicine as stomach pain relief, against gastritis, diarrhoea, bilharzias, dysmenorrhoea, liver disorders, fever, female infertility, genitourinary infections, snake and scorpion bites, leprosy, cough, asthma, kidney stones, arthritis, cardiovascular diseases, and general tiredness (Hutchings et al., 1996; Van Wyk et al.,1997; Quazi Majaz et al., 2011).

1.4 Hypotheses

We hypothesize a positive effect of kalanchoe pinnata aqueous extract in protecting animals against hypertension and myocardial infarction.

1.5 Objectives of the study

1.5.1 General objective

– To determine the effects of kalanchoe pinnata aqueous extract on some biochemical makers in salt loaded rats

1.5.2 Specific objectives

• To determine the effects of kalanchoe pinnata aqueous extract on total cholesterol, low density lipoproteins, triglycerides.
• To determine the effects of kalanchoe pinnata aqueous extract on the cardiac troponin-T in concurrent salt loaded rats and isoprenaline induced myocardial infarction.