Green synthesis of silver Nano particles by using (Rheum) extract and its anti-bacterial activity

Silver nano particles have wide potentials in the medicine and other fields. there are many approaches used to synthesis ag nps: chemical, physical and green approach. green approach favorited over other methods, because it is simple, ecofriendly, cheap. in this work we synthesized ag nps using stem of rheum. this plant used by humans as dietary material ,and found in the hills .added silver nitrate solution to rheum extract gragualy, appear yellow color solution indicated on formation ag nps as a result of surface plasmon resonance. ag nps was characterized by using different techniques , uv-visible spectroscopy, x-ray diffraction, atomic force microscopy, scanning electron microscopy and zeta potential which provide that ag nps was stable without addition stabilizing agent .ag nps used in medical field as active anti-bacterial against three pathogens bacteria, staph-aureus g+,proteus g+,e-coli g-