Although in vitro and in vivo ACE inhibition activity of some flavonoids such as quercetin and phenolics such as ferulic acid and tannic acid have been studied [20,21], the data on ACE inhibition and therefor blood pressure-reducing potency of many more flavonoids, especially those that are present in OS (a plant that has been used traditionally for treating hypertension), have not yet been studied. The gene discussed is ACE; the disease is Hypertension.