Evaluation of the antibacterial activity of Syzygium cordatum fruit-pulp and seed extracts against bacterial strains implicated in gastrointestinal tract infections

Abstract

Gastrointestinal tract (GIT) infections are the major cause of high morbidity and mortality rates, especially in the developing countries. Fruit and seed extracts possess phytochemicals that are active against bacterial strains implicated in GIT infections. Different parts of Syzygium cordatum trees have been investigated pharmacologically against GIT infections previously with the exception of the fruits and seeds. This study aimed at evaluating the antibacterial activity of S. cordatum fruits and seeds against bacteria causing GIT infections. The harvested fruits were separated into fruit-pulp and seeds, dried and extracted with methanol using Soxhlet extraction. The extracts were phytochemically screened and micro dilution assay was used to evaluate antibacterial activity of the fruit-pulp and seed extracts against the selected GIT infecting bacteria. The crude extracts of fruit-pulp and seed exhibited the percentage yield of 10 and 6, respectively. The extracts showed the presence of phytochemicals with the total phenolic content of 21.4±1.4 µg/ml for seed extract and 16.4±1.8 µg/ml for fruit-pulp extract. Antimicrobial activity of the pulp extract exhibited the lowest minimum inhibitory concentration (MIC) of 3.13 mg/ml against Bacillus cereus (ATCC 10102), Staphylococcus aureus (ATCC 25925), Klebsiella pneumoniae (ATCC 4352), Pseudomonas aeruginosa (ATCC 7700), Enterococcus hirae (ATCC 8043) while the seed extract had an equal MIC value against Klebsiella pneumoniae (ATCC 4352). The antimicrobial activity was due to the detected phytochemicals and thus promoting S. cordatum fruits and seeds as potential new and cost effective sources for prevention and treatment of GIT infections.

Keywords: Gastrointestinal, fruits, seeds, phytochemicals.

Abbreviation: GIT, Gastrointestinal tract; DMSO, dimethyl sulfoxide; MIC, minimum inhibitory concentration; MBC, minimum bactericidal concentration.