Simple and Sensitive Method for Pyrroloquinoline Quinone (PQQ) Analysis in Various Foods Using Liquid Chromatography/Electrospray-Ionization Tandem Mass Spectrometry

Abstract

Pyrroloquinoline quinone (PQQ) is believed to be an important factor for mammalian growth and development and has, therefore, been declared a vitamin by some researchers. However, this issue remains controversial, and from a nutritional viewpoint, accurate determination of PQQ levels in a variety of foods is very important. Here, we describe a simple, highly sensitive, and highly selective method for quantitative analysis of PQQ. Liquid foods or aqueous extracts of solid foods were analyzed using high-performance liquid chromatography (HPLC) combined with electrospray-ionization (ESI) tandem mass spectrometry (MS/MS). (15)N-labeled PQQ was added to the samples as an internal standard. Quantitative analyses of PQQ were performed by multiple reaction monitoring (MRM) with LC/MS/MS. Free PQQ was detected in almost all food samples in the range 0.19-7.02 ng per g fresh weight (for solid foods) or per mL (liquid foods). This method will enable the rapid and simple determination of PQQ levels in many samples.

The Effect of Pyrroloquinoline Quinone (PQQ) on Viability of Human Colorectal Adenocarcinoma HT-29 Cell Line

“…There is no evidence that PQQ can be synthesized in cells of higher organisms (mammals). However, PQQ has been detected in low quantities (in the order of nanograms) in human serum, breast milk, in different plants and foods such as kiwi, egg, milk and in fermented products such as sake and wine (Noji et al, 2007). It has been suggested that PQQ, present in the human organism, could have its origin from the bacteria present in the digestive tract, although it is not known precisely the functions that PQQ could perform in humans.…”

“…PQQ is a polyphenolic compound, found in plants, animal cells, various foods and biological fluids. Several authors have proposed to PQQ as a new vitamin (Bauerly et al, 2011;Flores-Encarnación et al, 2014;Noji et al, 2007;Rucker et al, 2009). PQQ was first recognized as a bacterial cofactor in 1979, until date it has been purified and crystallized (Satyabrata et al, 2013;Stites et al, 2000).…”

Photoionisation and photodissociation studies of nonvolatile organic molecules by synchrotron VUV photoionisation mass spectrometry and theoretical calculations

“…These kinds of compounds exist widely in nature; they have a variety of important characteristics for biological activities and play vital roles in biological systems [90]. The mass spectrometric analysis of quinones has been well established for several decades by GC/EI-MS [89], MALDI TOF-MS [91], ESI-MS [92][93][94], atmospheric pressure chemical ionisation mass spectrometry (APCI-MS) [95] and L2MS [96]. …”

Crystal Structure and Function of PqqF Protein in the Pyrroloquinoline Quinone Biosynthetic Pathway

“…Recently, sugar oxidoreductase in the basidiomycete Coprinopsis cinerea (6), 2-keto-D-glucose dehydrogenase from Pseudomonas aureofaciens (7) and pyranose dehydrogenase from C. cinerea (8) were all characterized as novel PQQ-dependent enzymes. Free PQQ has been identified in a wide variety of foods (9) and milk (10). PQQ is an essential nutrient for proper growth and development in mice (11).…”