An evaluation of nutraceutical components of syzygium cordatum fruits for the treatment of gastrointestinal tract infections

Abstract
Gastrointestinal tract (GIT) infections represent high morbidity and mortality rates worldwide annually due to malnutrition, microbial drug resistance and newly emerging GIT infections. Although the pharmacological activities of different parts of Syzygium cordatum have previously been determined, the nutraceutical value of its fruits and seeds has not been reported. This study aimed at evaluating the nutraceutical value of the fruits and seeds of S. cordatum in pursuant to discovering newer and more cost-effective means to prevent GIT infections. The harvested fruits were separated into pulp and seeds, dried and extracted separately with 100% methanol using the Soxhlet extraction method. Proximate analysis was determined using the Association of Official Analytical Chemists (AOAC) standard methods and the energy content was calculated arithmetically. The extracts were screened for phytochemicals and microdilution assay was used to evaluate antibacterial activity of the fruit extracts against the selected GIT infecting bacteria and assayed for cytotoxicity using MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide) assay. The in vivo antidiarrhoeal activity was determined using the castor oil-induced rat model. The pulp and seed extracts revealed carbohydrate content of 63.9 and 60.5 %, respectively and the concentrations of the elements (potassium, calcium, iron, zinc and boron) had a range of 0.05 to 151 mg/L. The pulp and seed extracts contained 327 kj/g and 347 kj/g of the energy content, respectively. The pulp extract exhibited 16.4±1.8 μg/mg of total phenolic content while the seed extract had 21.4±1.4 μg/mg. Antibacterial property of the pulp extract revealed it to have the lowest MIC of 3.13 mg/ml against Bacillus cereus (ATCC 10102), Staphylococcus aureus (ATCC 25925), Pseudomonas aeruginosa (ATCC 7700) and Enterococcus hirae (ATCC 8043) while the seed extract had the lowest MIC value (6.25 mg/ml) against Bacillus cereus (ATCC 10102), Staphylococcus aureus (ATCC 25925) and Enterococcus hirae (ATCC 8043). Fruit-pulp extract gave the median inhibitory concentration (IC50= 92 μg/ml) and the therapeutic index (0.1 - 0.3). The in vivo antidiarrhoeal activity showed the percentage inhibition of 41 for the seed extract and 49 for the pulp extract at 400 mg/kg, respectively. The antibacterial and antidiarrhoeal activities were assumed to be due to the detected phytochemicals and thus promoting S. cordutum fruits and seeds as safe, potential nutraceutical sources against GIT infections.
Description
A dissertation submitted to the Faculty of Science and Agriculture in fulfilment of the requirements for the degree of Master of Sciences in the Department of Biochemistry and Microbiology at the University of Zululand, South Africa, 2015
Keywords
gastrointestinal tract infections --syzygium cordatum --diseases
Citation