Biomedical subjects

T Urakami

Publications and source records attributed to T Urakami.

39 records · Page 3Linked to original sources

PubMedDate not supplied

The protective effect of pyrroloquinoline quinone and its derivatives against carbon tetrachloride-induced liver injury of rats.

Pyrroloquinoline quinone (PQQ) and its derivative, oxazo pyrroloquinoline (OPQ-G), protected rats from experimental liver injury induced by carbon tetrachloride (CCl4) in vivo. This effect was observed after an intraperitoneal injection of 5 mg/kg PQQ or OPQ-G, which was given twice, 10 min and 1 h before CCl4 administration. Pyrroloquinoline quinone protected primary cultured rat hepatocytes from CCl4 toxicity in vitro. This protection was most effective at a concentration of 3 mumol/L PQQ. Pyrroloquinoline quinone derivatives (oxazo pyrroloquinoline, methyl-thioethyl oxazo pyrroloquinoline and PQQ-allylester) also protected the hepatocytes from CCl4 toxicity. Pyrroloquinoline quinone and its derivatives inhibited the lucigenin-enhanced chemiluminescence from isolated hepatocytes initiated by CCl4. These results suggest that eliminating free radicals is one of the protective mechanisms of PQQ and its derivatives against CCl4-induced liver injury.

Acridines↗

PubMedDate not supplied

Characterization of imidazopyrroloquinoline compounds synthesized from coenzyme PQQ and various amino acids.

Imidazopyrroloquinoline (IPQ) compounds synthesized from coenzyme PQQ (pyrroloquinoline quinone) and various kinds of amino acids were characterized. IPQ was synthesized from coenzyme PQQ and one of three amino acids (glycine, L-tryptophan and L-tyrosine). Two kinds of IPQ compound were formed from coenzyme PQQ and L-serine. At higher pH, IPQ was synthesized, at lower pH hydroxy-methyl-IPQ was synthesized. IPQ with R of amino acids represented by R-CH(NH2)-COOH was synthesized from coenzyme PQQ and other amino acids. IPQ compounds do not act as cofactor of glucose dehydrogenase. Molar absorption coefficients of IPQ are 31,400 M-1 cm-1 at 251 nm, 30,700 M-1 cm-1 at 276 nm, and 20,700 M-1 cm-1 at 423 nm at pH 7.0 and room temperature.

Amino Acids↗

PubMedDate not supplied

Synthesis of esters of coenzyme PQQ and IPQ, and stimulation of nerve growth factor production.

Esters of pyrroloquinoline quinone (PQQ), a cofactor of microbial quinoprotein enzyme, and imidazopyrroloquinoline (IPQ, from PQQ and glycine) were synthesized, and their chemical stability, toxicity to L-M cells and nerve growth factor (NGF) inducing activity in L-M cells were studied. PQQ esters were found to be potent enhancers of NGF production, but IPQ esters had only marginal effects on NGF production. The monoester of PQQ with a methoxycarbonyl group at C-2 of PQQ is a most effective compound because of its NGF inducing activity, limited toxicity, safety and chemical stability. These results suggest that PQQ-2-esters could be developed as a curative or preventive drug for retrograde neural diseases in the central and perpheral nervous system.

Animals↗