The importance of flavonoids in reducing blood pressure - selected aspects

Hypertension is an independent risk factor for the development of cardiovascular disease. Therapy requires modifying the diet and lifestyle in order to reduce body weight. The role of flavonoids in reducing blood pressure also seems interesting. Flavonoids are plant compounds. The main classes of flavonoids are flavons, isoflavons, flavonols, flavanols, flavanones, and anthocyanins. Numerous epidemiological studies have reported that a higher intake of flavonoids in a diet is associated with a decreased risk of hypertension. One of the mechanisms by which flavonoids can help to reduce blood pressure is their activity as angiotensin-converting enzyme (ACE) inhibitors. Various flavonoids have a different ability to inhibit ACE, which is dependent on their chemical structure. The ACE inhibitor activity is associated with three structural elements of flavonoids: the catechol group on the B-ring, C2-C3 double bond and the cetone group in C4 at the C-ring. Flavonoids may exhibit ACE inhibitor activity because of compete with the substrate (competitive inhibition). One of the studies showed that flavonoid activity, as an ACE inhibitor, may be dependent on the ACE genotype (I/I, I/D, D/D). The vasodilatory properties of flavonoids can help lower blood pressure. Authors of numerous studies have shown that these properties are associated with different mechanisms, e.g. activation of potassium channels, regulation of extracellular and intracellular Ca2+ level, stimulation of nitric oxide synthase and increased synthesis of nitric oxide. Based on the studies presented in this paper, it can be concluded that flavonoids may play an important role both in preventing hypertension and in supporting its treatment.