LAUSR

The term "vitamin P" is an old, but interesting concept. Most of them belong to the family of flavonoid. "vitamin P" also has been used to define the activity of some flavonoids including quercetin, myricetin, rutin, etc. According to the experimental studies, the "quercetin-like nature plant flavonoids" have beneficial to the body due to have the various physiological and pharmacological activities in large doses (5μM in vitro, 50mg/kg of mice and 100mg/kg of rats. etc). Considering the physiologically achievable concentration is 10 to 100 nM, these large doses are hard to reach in normal diet. Thus, the physiologic activity and mechanism of "vitamin P" is still not clear. It should be noticed that the quercetin-like nature plant flavonoids are naturally physiological co-factor of cyclooxygenases (COXs) which is the rate-limiting key enzymes of prostaglandins. These quercetin-like nature plant flavonoids could strongly stimulate the prostaglandin level in lower doses (10 nM in vitro and in 0.1mg/kg vivo of rats). Although these "vitamin P" is not the original organism in body, the physiological function could not ignore to the body. This review focused on the most compelling evidence regarding the physiologic role and mechanism of quercetin-like nature plant flavonoids, which may be useful in understanding the physiological functions of "vitamin P", and lead to focus on the role of flavonoids on human physiological health.