Anti-Obesity, Cognitive Enhancing, Neurobehavioral, Antioxidant Effects And Phytochemical Profile Of Dichloromethane Leaf Extract Of Gnidia Glauca (Fresen)
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Date
2019-11
Authors
Makori, Wycliffe Arika
Journal Title
Journal ISSN
Volume Title
Publisher
Kenyatta University
Abstract
Obesity is a chronic metabolic disorder characterized by increased adipose tissue mass due to positive energy balance. The epidemic of obesity is currently on the rise probably due to increasingly sedentary lifestyles combined with easy availability of palatable, high-fat foods. It presents modifiable risk factor for cognitive impairements, anxiety and motor deficits. Globally, its prevalence has shown a startling increase in all age groups and have been associated with increased morbidity and mortality. Prescription of anti-obesity drugs can be useful adjuncts to diet and exercise for obese patients who have failed to achieve weight loss. However, these drugs are ineffective, not readily available, unaffordable and have been associated with adverse effects. Therefore, medicinal plants have drawn a sharp focus in recent times as complementary and alternative medicines owing to their biocompatibility, affordability and are assumed to be safe due to their long-term clinical application. Hereby, determination of therapeutic activities and identification of active principles from herbal prescriptions have become the prime focus in the validation of their folkloric usage and in drug discovery programs. The present study aimed to determine the anti-obesity effects, cognitive enhancing, neurobehavioral, antioxidant effects and phytochemical profile of dichloromethane leaf extract of Gnidia glauca. Obesity was experimentally induced by feeding the rats with prepared high-fat-diet (HFD) and water ad libitum for a period of 6 weeks. The in-vivo anti-obesity effects were determined by oral administration of the extract at dosage levels of 200, 250 and 300mg/kg body weight in HFD-induced obese rats from the 6th to 12th week along with HFD. Cognitive-enhancing effects of the extract in HFD-induced obese rats were determined using the Morris Water Maze experiment. The effects of the extract on neurobehaviors (locomotor activity, anxiety and exploration-like behaviors) in HFD-induced obese rats were tested using the Open Field Test. The in vitro antioxidant properties of the extract were determined using non-enzymatic assays. The phytochemical profile of the extract was determined using GC-MS. The results indicated that the extract exhibited potent anti-obesity effects in HFD-induced obese rats. It significantly reduced the body weight, organ weights, organo-somatic indices, anthropometric indices, the total fat content, adiposity index, atherogenic index as well as the lipid profiles (Triglycerides, Total Cholesterol, Low-Density Lipoproteins, and Very Low-Density Lipoproteins). However, it significantly increased levels of High-Density Lipoproteins. The extract increased levels of white blood cells, differential leukocyte counts, platelet count as well as red blood cells and related parameters. The extract improved hippocampal-dependent spatial learning and memory retention in HFD-induced obese rats. Moreover, it showed anxiolytic effects, increased spontaneous locomotor activity and exploration-like behaviors in HFD-induced obese rats. The extract also indicated in vitro antioxidant effects. The phytochemical analysis revealed the presence of 28 bioactive compounds in the extract. The anti-obesity effects, antioxidants activities, cognitive-enhancing effects and the improved locomotor and exploration-like behaviors could be attributed to the phytochemical compounds present in the plant extract. The present study, therefore, scientifically validated the traditional use of this plant and generated data that can serve as guide in the recruitment of the extract as a potential candidate for the synthesis of a new effective drug against obesity and associated complications. However, there is a need for bioassay-guided fractionation of bioactive compounds in Gnidia glauca. Besides, it is recommended to conduct comprehensive toxicity studies to establish the safety profiles of Gnidia glauca.
Description
A Thesis Submitted in Fulfilment of the Requirements for the Award of the Degree of Doctor of Philosophy (Medical Biochemistry) in the School of Pure and Applied Sciences of Kenyatta University, November, 2019
Keywords
Anti-Obesity, Cognitive Enhancing, Neurobehavioral, Antioxidant Effects, Phytochemical, Dichloromethane, Gnidia Glauca (Fresen)