| This experiment was carried out for extracting catechins from the seeds of two different species of grapes named( Shadaa Sodda and Bedha).The extractions were tested as antimicrobial,and was carried out in two methods , mix sample with distilled water (1:10) and with ethyl acetate ethyl acetate and distilled water (10:90) adding 50 ml hexane for economic reason, active samples have been tested against some organism (7 of them were bacteria) Bacillus stearothermophilus, Bacillus cereus , Bacillus subtitlis, Salmonella typhimurium , staphylococcus aureus , Escherishia coli and Pseudomonas fluorescens,and 2 of them were Yeasts ; Kluyveromyces marxianus and candida albicans ,and 2 of them were Molds ; Aspergillus niger and Rhizobus stolonifer .for the later, the method of disk diffusion and agar dilution method were used. : the antimicrobial effectiveness for extracts were verified according to the variation of the extracts and the microorganism type. While the yeasts and molds showed less sensitivity toward the extracts, except waste grape juice extract which showed antimicrobial activity against A. niger with proportion of7.14 and 22.4% at the concentration 200 microgram/ ml.Upon the qualitative estimation of inhibition effectiveness for the three extracts against bacteria, E.coli ,Bacillus cereus and B.stearothermophilus were choosed. and the limited inhibition was estimated , there was no inhibition at 100 ppm , while the concentrations 250 ppm for both grape seeds extract and the concentrations 500ppm for waste grape juice extract,were the best inhibition concentrations. against the three bacteria mentioned . The percentage of inhibition of the concentrations used at 250, 500 ,750 and 1000 ppm against the bacteria B.stearothermophilus were 30.76, 53.84, 23.07 and 7.69% respectively,and the percentage of inhibition of Bacillus cereus were 77.33, 81.33, 66.66 and 66.66% respectively,and the values of inhibition of bacteria, E. coli were 90, 93.75, 75 and 63.75%respectively. |