There are scarce evidences about the effects of herbs on nitrogen species that induced nitrosative stress. We here investigated the effect of simple water distilled extract of dry leaves salvia officinalis (sage) and Ruta graveolens (Rue) on the nitric oxide (NO) - peroxynitrite (ONOO-) cycle biochemistry in vitro experiments. Aqueous extract of sage or rue (1%) were prepared by simple distillation and scanned by UV-visible spectrophotometer. Their effects were studied on the synthesized ONOO- as well as their ability to generate ONOO. It is ability to donate NO or to scavange released NO by sodium nitroprusside (10 mM) also investigated. UV-visible scan of sage extract revealed the presence of peaks at λ195 and 348.5 while that of rue extract at λ 200, λ242, λ291.5. Both extracts not generate ONOO- radical in form of nitrophenols. Rue extract increased the yield of prepared ONOO- by more than five times. Rue extract donated NO and improved the release NO from sodium nitroprusside while sage extract only improved the release of NO released by sodium nitroprusside. We conclude that simple distilled - aqueous extract of rue and sage extracts improved nitric oxide bioavailability that may be helpful in coronary artery disease with nitrate tolerance.