Species differences in the aromatization of quinic acid in vivo and the role of gut bacteria

Abstract

1. The fate of (-)-quinic acid has been investigated in 22 species of animals including man. 2. In man and three species of Old World monkeys, i.e. rhesus monkey, baboon and green monkey, oral quinic acid was extensively aromatized (20-60%) and excreted in the urine as hippuric acid, which was determined fluorimetrically. 3. In three species of New World monkeys, i.e. squirrel monkey, spider monkey and capuchin, in three species of lemurs, i.e. bushbaby, slow loris and tree shrew, in the dog, cat, ferret, rabbit, rat, mouse, guinea pig, hamster, lemming, fruit bat, hedgehog and pigeon, oral quinic acid was not extensively aromatized (0-5%). 4. In the rhesus monkey, injected quinic acid was not aromatized, but largely excreted unchanged. 5. In rhesus monkeys pretreated with neomycin to suppress gut flora, the aromatization of oral quinic acid was considerably suppressed. 6. In rats and rhesus monkeys [(14)C]quinic acid was used and this confirmed its low aromatization in rats and its high aromatization in the monkeys. 7. Shikimic acid given orally was excreted as hippuric acid (26-56%) in rhesus monkeys, but not in rats. 8. The results support the view that quinic acid and shikimic acid are aromatized by the gut flora in man and the Old World monkeys.

Discovery of Quinic Acid Derivatives as Oral Anti-inflammatory Agents

“…QA was converted into benzoic acid by gut flora in all species (Figure 1-4). 27,73,86 In summary, bioavailability of QA in animal is very low.…”

“…85 Adamson in 1970 reported that the aromatization of QA was different between animal species, and gut bacteria played an important role in this process. 27 In man and some old world monkeys, oral quinic acid was extensively aromatized (20-60%) and excreted in the urine as hippuric acid. The aromatization of oral quinic acid was considerably suppressed when gut flora were suppressed by neomycin.…”

“…77,78 Caffeic acid (CA) and QA were liberated and further metabolized. 27,79 The proposed CGA metabolism pathway is shown in Figure 1-4. Some of the microbial metabolites still bearing a free phenolic group could act as antioxidants.…”

“…High levels of QA catabolizing enzymes in gut bacteria is consistent with the finding that less than 10% of an orally administered dose QA is recovered in rats. 27 One of the significant enzymes of QA degradation is QDH. QDH has been purified and characterized, and been extensively studied in fields such as catabolism and antibacterials.…”

“…High levels of QA catabolizing enzymes in gut bacteria is consistent with the finding that less than 10% of an orally administered dose QA is recovered in rats. 27 Our goal was to discover and develop stable QA derivatives as orally drugs, and to study the bioavailability of QA and its derivatives. …”