Increased Urinary Hydrogen Peroxide Levels Caused by Coffee Drinking.

Abstract

Experiments with volunteers in Singapore have demonstrated that coffee drinking increases urinary hydrogen peroxide levels (Long, Halliwell, Free Rad. Res., 32, 463-467 (2000)). We re-examined the effect of coffee drinking of healthy Japanese subjects on urinary hydrogen peroxide levels. A cup of brewed or canned coffee commercially available in Japan generated 120-420 m mmol hydrogen peroxide in incubation in a neutral medium at 37°C for 6 h. The increased levels were higher than those obtained from a cup of green tea extract or a glass of red wine. After the subject drank a cup of coffee, apparent hydrogen peroxide levels (m mmol/g creatinine) in urine collected 1-2 h after coffee drinking increased 3-10-fold compared to the levels before coffee drinking. The increased urinary hydrogen peroxide levels are likely derived mainly from 1,2,4-benzenetriol excreted in urine, because the major component that generates hydrogen peroxide is found to be 1,2,4-benzenetriol, and storing urine collected after coffee drinking increased hydrogen peroxide levels in a time-dependent fashion. Total hydrogen peroxide equivalent levels excreted in 3 h-urine after coffee drinking were estimated to be 0.5-10% that of coffee consumed. A residual amount of hydrogen peroxide may be retained or consumed in human bodies.

Anti-proliferative and pro-apoptotic activities of hydroxytyrosol on different tumour cells: the role of extracellular production of hydrogen peroxide

“…(increasing the pH), which moves the equilibrium to the right. Although the oxidation of catechol can also be due to the transition metals such us Cu and Fe [38] [32,33], myricetin [31] and theaflavin-3 0 3 0 -digallate [39], while it enhances the accumulation of H 2 O 2 induced by para-aminophenol [17] and canned coffee [22]. In this context, it should be underlined that the reactions behind the H 2 O 2 -releasing activity of 3,4-DHPEA may be particularly complex and deeply influenced by the experimental conditions.…”

Urinary Hydrogen Peroxide and Renal Function Parameter of Type 2 Diabetes Mellitus Patients Consuming Metformin and Metformin-Sulfonylurea

“…Some study reported that urinary H 2 O 2 level was influenced by coffee drinking. 15 To avoid the bias effect of drink and foods, patients were fasting at least 8 hours before taking their urine and blood. The concentration of urinary H 2 O 2 in both groups were not a significant difference.…”

H2O2-induced Kinetic and Chemical Modifications of Smooth Muscle Myosin

“…In general, healthy smooth muscle is quite resistant to exogenous H 2 O 2 . The most extreme example is agonist activated bladder smooth muscle (bladder concentrations of H 2 O 2 often reach levels of 0.2-0.4 mM in healthy adults (21), which was shown to exhibit an EC 50 for relaxation of 36 mM H 2 O 2 (22)). Airway smooth muscle, although considerably more sensitive than bladder, still requires nearly mM concentrations of H 2 O 2 for relaxation of agonist induced contraction (23).…”