Antimicrobial Activities of Polysaccharides Isolated from Some Plant Seeds

The present investigation is about the measurement of antimicrobial activity (AMA) of polysaccharides isolated from the seeds of pumpkin (Cucurbita pepo), purslane (Portulaca oleracea), safflower (Carthamu stinctorius),coriander (Coriandrum sativum) and rapeseed (Brassica napus) against Staphylococcus aureus (S.aureus), Escherichia coli (E.coli), Bacillus subtilis (B.subtilis) and (MRSA) at different concentrations using agar diffusion method In vitro. Polysaccharides (PSs) were extracted, isolated and purified from different seeds separately. Paper chromatographic analysis of the purified PSs, revealed the presence of different percentages of monosaccharides constituents per each seed PS. In vitro study was performed to evaluate the obtained PSs activities against 4 microbial strains (S. aureus, E. coli, B subtilis and MRSA) using agar diffusion method. PSs showed AMA against S. aureus and E. coli more than that of B subtilis and MRSA at 10% concentration and inhibition zones were estimated. Minimal inhibitory concentrations (MIC) of PSs against S. aureus, E. coli, B subtilis and MRS were found in the range of 1-5 mg/ml. The result demonstrates the killing effect of PSs against S. aureus, E. coli, B subtilis and MRSA at 10% PS within 24 hours. Inhibition zone diameters exhibited different levels of decreases with the PSs concentrations decreases against S. aureus, E. coli, B. subtilis and MRSA. Inhibition effects of PSs against different microbial strains were found to be depending on PSs concentration. However, the lowest concentration of PSs produced lower inhibitory activity against S. aureus B. subtilis E. coli and MRSA. The results obtained with all PSs showed best AMA against S. aureus and E. coli than the other two microbial strains used in the present study. Results indicated these PSs have AMA against Gram-positive and Gram-negative bacterium at 10% concentration. The common PSs consider important sources of antimicrobial agents with minimal inhibitory concentrations of 100-500µg/ml for treatment some infectious diseases.