Dietary Sources of Pyrroloquinolone quinone (PQQ)


Pyrroloquinolone quinone, also known as PQQ, is the third redox cofactor after nicotinamide and flavin in bacteria within the intestine. 

PQQ has been shown to have a variety of benefits to health in the following areas:

  • Cardiovascular
  • Cell metabolism
  • Metabolism
  • Neurological

The Table below lists some of the studies conducted on PQQ.  In no way is this list all inclusive, yet it demonstrates that PQQ has many biologically protective properties.

Health Benefits of Pyrroloquinoline Quinone (PQQ)

Cerbral Insufficiency
In this study, the authors demonstrate a neuroprotective effect of pyrroloquinoline quinone in an in vivo cerebral hypoxia/ischemia model in the rodent.1
Heart attack
PQQ given either as Pretreatment or as Treatment at the onset of reperfusion is highly effective in reducing infarct size and improving cardiac function in a dose-related manner in rat models of ischemia and ischemia/reperfusion. The optimal dose in this study, which exhibited neither renal nor hepatic toxicity, was 15 mg/kg, but lower doses may also be efficacious. The authors conclude that PQQ, which appears to act as a free radical scavenger in ischemic myocardium, is a highly effective cardioprotective agent.2
PQQ at 10 mg/kg infused at the initiation, or 3 h after the initiation, of rMCAo was effective in reducing cerebral infarct volumes measured 72 h later. At 3 h after ischemia, a dose of 3 mg/kg significantly reduced infarct volume compared to vehicle-treated animals, but 1 mg/kg was ineffective. Neurobehavioral scores were also significantly better in the PQQ-treated group compared to the vehicle controls when PQQ was given at 10 and 3 mg/kg, but not at 1 mg/kg. Thus, PQQ is neuroprotective when given as a single administration at least 3 h after initiation of rMCAo. These data indicate that PQQ may be a useful neuroprotectant in stroke therapy.3
Cell Metabolism
Mitochondrial Biogenesis
Recent studies corroborate the unique ability of PQQ to stimulate the formation of new mitochondria and improve the function of existing mitochondria.  5
PQQ acts as an antioxidant by significantly enhancingd the activities of superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx)6
Glutamate-induced neurotoxicity
In this study, the neuroprotective effects of PQQ were observed by pretreatment of NS/PCs with PQQ before glutamate injury, and the possible mechanisms were examined. PQQ stimulated cell proliferation and markedly attenuated glutamate-induced cell damage in a dose-dependent manner. 7
Rats fed a PQQ-supplemented diet showed better learning ability than rats fed a CoQ(10)-supplemented diet at the early stage of the Morris water maze test. The combination of both compounds resulted in no significant improvement in the learning ability compared with the supplementation of PQQ alone. At the late stage of the test, rats fed PQQ-, CoQ(10)- and PQQ + CoQ(10)-supplemented diets showed similar improved learning abilities.8
Nerve growth factor
PQQ supplementation stimulates the production and release of nerve growth factors in cells that support neurons in the brain9
Parkinson’s disease
Pyrroloquinoline quinone (PQQ) has been shown to play a role as an anti-oxidant in neuronal cells and prevent neuronal cell death in a rodent stroke model. DJ-1, a causative gene product for a familial form of Parkinson's disease, plays a role in anti-oxidative stress function by self-oxidation of DJ-1. 10
N-methyl-D-aspartate (NMDA) receptor
Under in vitro conditions in which PQQ is presented without an exogenous electron donor, it appears as if the entire neuroprotective effect of PQQ is attributable to a direct oxidation of the NMDA receptor redox site. These results suggest the possibility of a novel role for PQQ, PQQ-like substances, and quinone-containing proteins in the brain, and may represent a novel therapeutic approach for the amelioration of NMDA receptor-mediated neurotoxic injury.11
Mercury induced neurotoxcitity
PQQ significantly decreased the production of ROS, suppressed the lipid peroxidation and increased the antioxidant enzyme activities in PC12 cells exposed to Methylmercury (MeHg). These observations highlighted the potential of PQQ in offering protection against MeHg-induced neuronal toxicity.12
Anti-amyloid fibril-forming reagent
This is the first study to demonstrate the characteristics of PQQ as an anti-amyloid fibril-forming reagent. Agents that prevent the formation of amyloid fibrils might allow a novel therapeutic approach to PD. Therefore, together with further pharmacological approaches, PQQ is a candidate for future anti-PD reagent compounds.13
Alzheimer’s disease
PQQ pretreatment recovered cells from Abeta(25-35)-induced cell death, prevented Abeta(25-35)-induced apoptosis, and decreased ROS production. PQQ strikingly decreased Bax/Bcl-2 ratio, and suppressed the cleavage of caspase-3. These results indicated that PQQ could protect SH-SY5Y cells against beta-amyloid induced neurotoxicity.14
Fibrillation of amyloid proteins
The fibril formation of mouse prion protein in the presence of PQQ was dramatically prevented. Similarly, the fibril formation of amyloid beta (1-42) also decreased. With further advanced pharmacological approaches, PQQ may become a leading anti-neurodegenerative compound in the treatment of neurodegenerative diseases.15

There are a number of foods that contain PQQ.  PQQ can be consumed as a separate or combined supplement or in the diet.  Supplementation will guarantee higher dosages of PQQ than in the diet, however, it is advisable to obtain PQQ first from the diet than supplement with capsules to obtain therapeutic dosages.  The usual therapeutic dosage of PQQ is considered to be 1 – 2 mg per day.

The Table below lists the foods that contain PQQ.  These food are sorted in descending order based on PQQ quantity.

Dietary Sources of Pyrroloquinolone quinone (PQQ) (in descending order)

FoodPQQ (ng/g)PQQ (mcg/g)PQQ (mg/g)
Green tea 29.60.02962.96E-5
Green pepper 28.20.02822.82E-5
Oolong (tea) 27.70.02772.77E-5
Kiwi fruit 27.40.02742.74E-5
Papaya 26.70.02672.67E-5
Spinach 21.90.02192.19E-5
Broad bean 17.80.01781.78E-5
Carrot 16.80.01681.68E-5
Potato 16.60.01661.66E-5
Cabbage 16.30.01631.63E-5
Sweet potato13.30.01331.33E-5
Banana 12.60.01261.26E-5
Green soybeans 9.260.009269.26E-6
Tomato 9.240.009249.24E-6
Bread 9.140.009149.14E-6
Orange 6.830.006836.83E-6
Celery 6.330.006336.33E-6
Apple 6.090.006096.09E-6
Wine 5.790.005795.79E-6
(Source: Levels of pyrroloquinoline quinone in various foods)

Clearly, natto contains the highest concentrations of PQQ than any other food.  Nattō, also known in Japanese as なっとう or 納豆 is a traditional Japanese food made from soybeans fermented with Bacillus subtilis var. natto.

Figure 1:  Natto


Megumi Organic Natto

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