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.