Project Materials

ANTI-HYPERLIPIDEMIC POTENTIAL OF VITEX DONIANAETHANOLEXTRACTS ON POLOXAMER 407 INDUCED HYPERLIPIDEMIC AND NORMAL RATS

ABSTRACT

The anti-hyperlipidemic potential of Vitexdoniana leaf, stem bark, and root bark extracts (aqueous, 70% methanol, 70% ethanol, and 70% acetone) in poloxamer 407-induced hyperlipidemic and normal rats was examined. Phytochemical analysis of the extracts revealed flavonoids, saponins, cardiac glycosides, alkaloids, and tannins in the leaves, stem bark, and root bark. The ethanol and methanol extracts of the leaves contained considerably more polyphenols (36.11±3.13mg/g gallic acid and 35.75±1.72mg/g gallic acid, respectively) than the acetone and aqueous extracts (p<0.05). The leaf ethanol extract had a lower IC50 (0.227mg/ml) than the stem bark ethanol extract (0.236mg/ml) and the root ethanol extract (0.561mg/ml). After screening the extracts for the most potent anti-hyperlipidemic activity, it was shown that ethanolic extracts of root bark and leaves had the largest percentage reduction in total cholesterol (51.98%) and triacylglycerol (50.75%), respectively. The leaf extract contains the highest concentration of flavonoids (4.605±0.077%), whereas the root bark extract contains the lowest concentration of tanins (0.035±0.008%). The LD50 of both leaves and stem bark was more than 5000 mg/kg body weight, whereas that of root bark was 948.68 mg/kg body weight. Control rats with hyperlipidaemia had significantly higher levels of total cholesterol (TC), triacylglycerol (TAG), low density lipoprotein (LDL-c), and lower levels of high density lipoprotein (HDL-c) than other groups (p<0.05). All treated rats with atherogenic risk factors had significantly lower levels of LDL-c/HDL-c, Log (TAG/HDL-c), and significantly higher levels of HDL-c/TC ratio (p<0.05). Normal control rats and normal treatment rats showed no significant (p>0.05) difference in lipid profile parameters or atherogenic indices. Hyperlipidemic control groups had significantly higher (p<0.05) levels of liver marker enzymes (ALT, ALP, AST) and lower levels of liver function parameters (TB, IB) than other groups. Hyperlipidemic groups had significantly higher (p<0.05) levels of TBARS and lower levels of SOD and CAT compared to other treated groups. The leaves and stem bark extract considerably (p<0.05) reduces TBARS levels in the liver and kidney of normal control rats compared to the normal treated and all induced treatment groups. All extracts in the liver and leaves extract in the kidney of normal rats exhibit significantly higher levels of CAT than other treated groups. The study demonstrates that vitexdoniana has antihyperlipidemic properties.

CHAPTER ONE

INTRODUCTION

Polyphenols are natural organic substances that have a significant number of phenol structural units (Quideau et al., 2011). The most research-informed and chemistry-aware definition of polyphenol is the White-Bate-Smith-Swain-Haslam (WBSSH) definition (Haslam and Cai, 1994)

which describes polyphenols as moderately water-soluble compounds with molecular weights ranging from 500 to 4000 Dalton, more than 12 phenolic hydroxyl groups, and 5-7 aromatic rings per 1000 Da.

The amount and features of phenol structures determine a polyphenol’s specific physical, chemical, and biological properties (Quideau et al., 2011).

Polyphenols have gained popularity among researchers and food makers during the last decade. The primary reason for this interest is the discovery of polyphenols’ antioxidant qualities, their abundance in our food, and their potential significance in the prevention of a variety of oxidative stress-related disorders, including cardiovascular, cancer, and neurological diseases.

It is the primary active ingredient in many therapeutic plants and regulates the action of numerous enzymes and cell receptors. Polyphenols, as antioxidants, aid in addressing and reversing the problems caused by oxidative stress to the walls of arteries, creating a heart-healthy environment by inhibiting the oxidation of low density lipoprotein cholesterol, thereby preventing atherosclerosis, and relieving chronic pain, as seen in conditions such as rheumatoid arthritis, due to their anti-inflammatory properties.

In addition to antioxidant properties, polyphenols have various other particular biological activities that are still unknown (Quideau et al., 2011).

Plants have been a source of medicinal substances for thousands of years, and an astounding number of modern medications have been identified from natural sources, many of which were used in traditional medicine (Hostettmann et al., 2000).

Approximately 90% of the world’s population relies on traditional medicines for primary care (Hostettmann et al., 2000). Recently, there has been a rise of interest in the therapeutic potentials of medicinal plants’ antioxidants in decreasing free radical-induced disorders.

It has been noted that the antioxidant activity of plants might be attributable to their phenolic components (Cook and Samman, 1996).