Description
CHAPTER ONE
- INTRODUCTION
- BACKGROUND
This research work is on Evaluation of the antidiabetic effects of water and methanolic extracts of avocado (persea americana) seed on alloxan induced diabetic rats. During the past decade, the traditional systems have gained importance in the field of medicine. The World Health Organization estimates that 4 billion people, 80% of the world population (WHO, 2002), presently use herbal medicine for some aspect of primary health care (Orisataoki and Oguntibeju, 2010). Eighty percent (80%) of African populations use some form of traditional herbal medicine (WHO, 2002.) and the worldwide annual market for these products approaches US$ 60 billion (Willcox and Bodeker, 2004). Herbal medicine is a major component in all indigenous people’s traditional medicine. Medicinal plants have continued to attract attention in global search for effective methods of using plants parts (e.g. seeds, leaves, stems, roots, barks etc) for the treatment of many diseases affecting humans (Sofowora, 2008). This is as a result of the continuous need for less expensive means of disease control.
Medicinal plants are plants which can be used for therapeutic purposes or which are precursors for the synthesis of useful drugs (Sofowora, 2008). Many important drugs used in healthcare today are directly derived from plants due to its bioactive constituents such as; alkaloids, tannins, steroids, etc. Examples include L-Dopa derived from Mucuna spp used for anti-parkinsonism, another is Caffeine, a CNS stimulant derived from Camellia sinensis and Quinine from Cinchona ledgeriana and used for Antimalarial, antipyretic.
As a matter of fact, well into the 20th century, much of the pharmacopoeia of scientific medicine was derived from the herbal lore of native people. Many drugs commonly used today are of herbal origin. Undisputedly, the history of herbology is inextricably intertwined with that of modern medicine. Many drugs listed as conventional drugs were originally derived from plants.
Salicyclic acid, a precursor of aspirin, was originally derived from white willow bark and the meadowsweet plant (Zand, et al., 2003).
Plants are very unique as their existence is very essential for the sustenance of the rest of the food chain. Based on the observations made through successive generations, superstition as well as traditional medicinal folklore, man has found and has been using herbs, barks, fruits, leaves, seeds, roots and stems of different plants of various climatic regions for therapeutic purposes (Sofowora, 2008).
- GLOBAL BURDEN OF DIABETES
Diabetes mellitus is a metabolic disease caused by a deficiency in the secretion or action of insulin (Nelson and Cox, 2005). This disorder is characterized by major symptoms as; polyuria (frequent and abundant urine), glycosuria (presence of glucose in urine) and hyperglycemia (glucose rate on an empty stomach higher than 1.2g/l in plasma blood and confirmed in at least two occasion) (N’guessan et al., 2009). Basically, there are two major clinical classes of diabetes. The type 1 diabetes or insulin dependent diabetes mellitus (IDDM) and type 2 diabetes or non insulin dependent diabetes mellitus (NIDDM) also called insulin resistant diabetes. According to the International Diabetes Federation (IDF) 2014 updates, out of the world seven billion population, 387million people, aged 20–79 years wor ldwide are diabetic, (IDF, 2014) giving a comparative prevalence of 8.3%, while 46.3% cases are undiagnosed. In every 7 seconds, a person dies of diabetes, 4.9 million deaths in 2014. Seventy seven percent (77%) of people with diabetes live in low and middle income countries. Africa has recorded cases of 2,150,274 (5.05%) diabetic patients with over 13million undiagnosed cases. In Nigeria, there are estimated 374,651 diabetic cases, with another 172,339 undiagnosed cases. These figures account for about 4.64% Nigerian adults between ages 20-79 living with diabetes (IDF, 2014). In 2014, about 105,090 Nigerians died as a result of diabetes (IDF, 2014). An average diabetic Nigerian spent about 43527.16 naira (US $178.39) in 2014 due to diabetes treatment (IDF, 2014). With this alarming prevalence rate, diabetes mellitus poses a major challenge globally and accounts for a number of disabilities and deaths globally.
Currently, diabetes therapy is based on the use of hypoglycemic drugs (sulfonamides, biguanides, and insulin), on hygieno-diet measures, exercise, and requires a lifelong treatment. With the level of poverty in developing nations like Nigeria, the need for a better and cheaper medication cannot be over emphasized. Traditional medicine has always provided a cheaper and time trusted alternative for the treatment and management of various diseases over time.
- STATEMENT OF PROBLEM
There is an urgent need to provide alternative and cheaper means for the management and treatment of diabetes.
- AIMS AND OBJECTIVES OF THE STUDY
This study is aimed at the evaluation of the anti-diabetic effects of water and mMETHANOLic extracts of Persea americana (avocado) seed on alloxan induced diabetic rats.
The specific objectives of the study are:
- To determine nutritional and some anti-nutritional constituents of seed extracts of the plant Persea americana.
- To evaluate the anti-diabetic properties of seed extracts of americana in diabetic rats
- To evaluate the effect of americana seed extract on liver function enzymes.
- To investigate the histopathological effects of americana on both the kidney and liver of diabetic rats.