[Development of polaprezinc research]

Abstract

Zinc, one of essential trace elements, functions as a structural component in more than 300 different enzymes in the human body, playing crucial roles in performing a number of functions, including protein and DNA synthesis. Also hereditary or dietary zinc deficiency leading to pathological changes such as growth retardation, skin symptoms and taste disorders in human has been well investigated. Polaprezinc (Promac(®), Zeria Pharmaceutical Co., Ltd.), a chelate compound consisting of zinc and L-carnosine, is a zinc-related medicine approved for the first time in Japan, which has been clinically used to treat gastric ulcers. Its mechanism of action is believed to oxygen radical scavenging, anti-oxidation, and acceleration of wound healing. Further, as zinc deficiency is known to be a primary cause of taste disorders, a clinical phase III study is in progress to determine taste disorders as a new indication of polaprezinc. The pharmacological action of polaprezinc, however, on taste disorders remains unclear. So we examined the effect of polaprezinc on taste disorders induced by feeding rats a zinc-deficient diet and clarified its mechanism of action in restoring the reduced zinc content in the lingual epithelium and improving delayed cell proliferation of taste bud cells due to zinc deficiency. In this review, we primarily make reference to our own data on the pharmacological action of polaprezinc on taste disorders and introduce recent research on the effects of polaprezinc in treating other diseases.