Inhibition of nitrate reducutase production from gramnegative bacteria using zizyphus spina-christi extract and comparing with some antibiotics

الملخص EN

Plants have an almost limitless ability to synthesize aromatic substances , most of which are phenols or their oxygen substituted derivatives.

these secondary metabolites could be utilized for benefit of mankind by studying their medical properties .

the study was performed for testing the effect of different Zizyphus.

spinachristi extracts (aqueous and alcoholic) on some gram negative bacterial growth in comparison with antibiotics , and compare their effects against nitrate reductase production by Brucella spp.

And other gram negative bacteria.

A total of nineteen diagnosed isolates were tested include : Brucella abortus, Brucella melitensis , Proteus spp.

, Klebsiella spp.

, Pseudomonas aeruginosa و Escherichia coli and Enterobacter spp.

These isolates originally isolated from clinical materials collected from patients .

the antimicrobial agents susceptibility test by disc diffusion method was performed using eight antibiotics.

the minimum inhibitory can centration (MIC) of the antibiotic (Ciprofloxacin) was determined for the most sensitive bacterial isolates.

The aqueous and alcoholic leaves and stem bark extracts were prepared in different concentration (10, 20, 40) % and the activity of the extracts was determined by measuring the diameter of inhibition zone using ager well diffusion method.

The inhibitory effect of ciprofloxacin and Z.

spina-christi aqueous and alcoholic extracts were determined against the nitrate reductase production by test microorganism using sub-MIC concentration of each materials.

The results showed highly significant p<0.05 antibacterial effect of Z.

spina-christi aqueous stem bark extracts on all the bacterial isolates specially Klebsiella spp.

(20 mm) and E.

coli (20 mm) compared with the leaves extracts (13 and 10) mm for Klebsiella spp.

and E.

coli respectively, at 40 % concentration, while the heist activity was determined by alcoholic stem bark extract at 40 % concentration against Klebsiella spp.

(13 mm) isolates .

the antibiotic susceptibility showed that all isolates were resistant to Ampicillin and Trimethoprim, while they were susceptible to Ciprofloxacin, Cefotaxime and Z.

spina-christi revealed inhibited the nitrate reductase production from all tested bacteria.

I can recommend that Z.spina-christi extracts have a good antibacterial effect against Brucella spp.

and other gram negative bacteria.

And the aqueous extracts of the stem bark is the best extract.

and both Ciprofloxacin and Z.

spina-christi extracts inhibited the production of nitrate reductase from all tested bacteria.