Physiologic Importance of Pyrroloquinoline Quinone

Abstract

Pyrroloquinoline quinone (PQQ, methoxatin) is a dissociable cofactor for a number of bacterial dehydrogenases. The compound is unusual because of its ability to catalyze redox cycling reactions at a high rate of efficiency and it has the potential of catalyzing various carbonyl amine reactions as well. In methylotrophic bacteria, PQQ is derived from the condensation of L-tyrosine with L-glutamic acid. Whether or not PQQ serves as a cofactor in higher plants and animals remains controversial. Nevertheless, a strong case may be made that PQQ and related quinoids have nutritional and pharmacologic importance. In highly purified, chemically defined diets, PQQ stimulates animal growth. Furthermore, PQQ deprivation appears to impair connective tissue maturation, particularly when initiated in utero and throughout perinatal development.

Regulation of oxidative stress and lipid peroxidation in PTU induced mice, treated with Pyrroloquinoline quinone (PQQ)

“…In vitro studies showed that PQQ protects isolated liver mitochondria from damage after oxidative stress and scavenges superoxide radicals (Smidt et al, 1991;Bishop et al, 1998;He et al, 2003). Previous in vivo studies of I/R injury in rats also suggested that PQQ reduces myocardial infarct size and improves cardiac function (Zhu et al, 2004).…”

“…(Hamagishi et al, 1990;Smidt et al, 1991;Aizenman et al, 1992;Bishop et al, 1994;Jensen et al, 1994;Ouchi et al, 2009;Xiong et al, 2011). Despite all these beneficial actions of PQQ, no attempt was made so far by any worker to evaluate its role in the regulation on the oxidative damage in hypothyroidic conditions.…”

Effects of Pyrroloquinoline Quinone and Vitamin C on Diabetes Associated Cardiac Oxidative Damages and Hyperlipidemia in Mice: Biochemical and Histopathological Study

“…8,9 Both in vivo and in vitro studies have shown that PQQ can protect against several types of oxidative damages and irradiation injury. 8,27 Potential role of PQQ, especially in DM, a disease which is strongly connected to cardiovascular complications was not yet known. Now the present study focuses on the effect of PQQ on the cardiovascular problems in STZ-induced diabetic mice.…”

“…In recent years, it has been reported that PQQ scavenges ROS, protects from oxidative stress and decreases the levels of free radicals as well as lipid peroxidation (LPO). [8][9][10] One report also suggested that PQQ reduces myocardial infarct size and improves cardiac function. 11 Both in vivo and in vitro studies have shown that PQQ can protect against several types of oxidative damages and irradiation injury.…”

“…Recently, workers found not only the involvement of ROS in the pathogenesis of CVDs, but also suggested the use of antioxidants which play a major role in reducing the oxidative stress by scavenging the excess free radicals. 8,9 In recent years several compounds with antioxidant properties have been found to be beneficial and may protect or restore physiological function in diabetes associated CVDs, mainly plant based compounds have been investigated in details. 12 However, the recently known PQQ has not been tried with respect to its cardio-protective potential in diabetes, if any.…”