evaluation of inhibitory activity of free and loaded quercetin on silver nanoparticles against urease enzyme

Aim and background: helicobacter pylori is a gram-negative, and transmissible pathogen that is present in 50% of the world s population, and causes a lot of disease like gastric cancer or mucosa-associated lymphoid tissue (malt) lymphoma.h.pylori could be survive in the acidic ph of stomach. as h. pylori enter the stomach, it generates urease, which stimulates the hydrolysis of urea, ultimately resulting in ammonia and carbon dioxide which causes bacteria to survive in acidic environment. therefore, virulence of h. pylori could be controlled using substances that inhibit urease activity. many urease inhibitors have been described in literature, that one of them is quercetin. quercetin is a polyphenolic flavonoid that has anti-cancer, anti-alzheimer and antibacterial properties. but it has not been successful in clinic trials due to its lack of aqueous solubility, low oral bioavailability, and difficulties crossing the blood-brain-barrier (bbb).in this study, in order to increase water solubility , and inhibitory activity of quercetin against of urease, it was pay loaded on ag nanoparticles. then inhibitory activity of free quercetin , and quercetin loaded on ag nanoparticles was investigated by in vitro assays.methods: at first, quercetin was loaded on the ag nanoparticles (nps ), in this process citrate sodium was used as reducing and stabilizing agent. then the urease inhibitory activity of free quercetin and payloaded on the ag nps was evaluated using berthelot method.results and discussion: the ic50 value for free quercetin and payloaded on ag nps was determined by berthelot assay. the determined ic50 values by enzymatic inhibition assay, confirmed the inhibitory activity of loaded quercetin is mor than free quercetin against urease.conclusion: due to various properties, including antioxidant properties, silver nanoparticles can be used as a very suitable drug carrier for targeted drug delivery, increasing drug solubility, and antibacterial activity. also, the results presented here indicates that the quercetin loaded on ag nps , could be successfully used as a urease inhibitor.