A series of 38 plants (55 plant extracts) from New Caledonia and 22 plants (40 plant extracts) from Vanuatu (Efate and Erromango islands) were screened for xan-thine oxidase (XOD) and elastase inhibitory activity. Of the crude extracts 82% were found to possess xanthine oxidase inhibitory activity, and 23% were active against elastase, at a concentration of 50 µg/ml. The methanol extracts of Cu...

Inhibition of xanthine oxidase by folic acid was reexamined after complete removal of the contaminant which was responsible for time-dependent inactivation (Lewis, A. S., Murphy, L., Mcalla, C., Fleary, M., and Purcell, S. (1984) J. Biol. Chem. 259, 12-15; Spector, T., and Ferone, R. (1984) J. Biol. Chem. 259, 10784-10786). From turnover experiments using stopped flow equipment with a limited a...

The enzyme, xanthine oxidase, has been implicated as a major source of destructive free radicals in ischemia-reperfusion injury associated with a range of pathological states [l]. Enzymic activity has been detected in many mammalian tissues [4] by using, variously, spectrophotometric [51, radiometric[6] and fluorimetric [71 assays. Apart from bovine milk fat globule membrane, which has long pro...

There is ample evidence in the literature concerning the labile nature of rat liver xanthine oxidase and its dependence on dietary protein. McQuarrie and Venosa (1) observed a large drop in the enzyme activity when the protein content of the ration was reduced from 25 to 10 per cent. Miller (2) noticed that a 7 day inanition caused a loss of xanthine oxidase activity in rat liver which exceeded...

Xanthine oxidase has been hypothesized to be an important source of biological free radical generation. The enzyme generates the superoxide radical, .O2- and has been widely applied as a .O2- generating system; however, the enzyme may also generate other forms of reduced oxygen. We have applied electron paramagnetic resonance (EPR) spectroscopy using the spin trap 5,5'-dimethyl-1-pyrroline-N-ox...

BACKGROUND Evidence supporting the role of xanthine oxidase in myocardial reperfusion injury is based on studies with pharmacological interventions used to inhibit enzyme function. Controversy exists, however, regarding the true role of xanthine oxidase in reperfusion injury. This study was performed to determine whether xanthine oxidase inhibition limits myocardial injury due to coronary arter...

Pleurotus cornucopiae has been widely used in nutritional and medicinal purposes. This study was initiated to screen the antioxidant activities, tyrosinase inhibitory effects on the fruiting bodies of P. cornucopiae extracted with acetone, methanol and hot water. The antioxidant activities were performed on β-carotene-linoleic acid, reducing power, DPPH, ferrous ions chelating abilities, and xa...

The reperfusion of previously ischemic tissue may lead to the formation of highly reactive free radicals that promote tissue injury. Xanthine oxidase has been implicated as one source of these free radicals. We examined the role of xanthine oxidase in brain injury using a cerebrospinal fluid compression model of global cerebral ischemia with 15 minutes of ischemia and 4 hours of reperfusion. Se...