natural antioxidants have an important role in the prevention of many age-related diseases and promotion of health. among natural antioxidants from plants, flavonoids and other phenolic compounds are potent antioxidants and chelating agents. moringa peregrina (forssk.) fiori (moringaceae) is a small desert tree distributed from tropical africa to east india. moringa tree is also growing in sout...

Cryptotanshinone and dihydrotanshinone I, constituents of a medicinal plant, Salvia miltiorrhiza Bunge, had antibacterial activity against a broad range of Gram positive bacteria. These compounds generated superoxide radicals in Bacillus subtilis lysates. A recombination-deficient mutant strain of B. subtilis was 2- to 8-fold more sensitive than a wild strain, and this hypersensitivity was redu...

Effect of free radicals on microvascular dimensions was studied in anesthetized cat intestinal mesentery. Generation of free radicals by xanthine oxidase, acting on endogenous substrates (e.g., xanthine, hypoxanthine), produced sustained vasodilation at pH 7.4 or at pH 6.6. These effects were reversed by superoxide dismutase (SOD), a superoxide radical (.O2-) scavenger, at pH 7.4, and by SOD pl...

Cytochrome c was reduced when superoxide was generated from xanthine oxidase in the presence of alloxan, and by the reaction of alloxan and with reduced glutathione. In each case, most of the reduction was inhibited by superoxide dismutase, but considerably more enzyme was required than with superoxide alone. This indicates that the superoxide dismutase-inhibitible cytochrome c reduction was ma...

The processes of oxidation are intrinsic in the management of energy of all living organisms and are, therefore, kept under strict control by several cellular mechanisms (Halliwell and Gutteridge, 2007). However, reactive oxygen species (ROS), generated during metabolism, are very unstable and highly reactive, due to the presence of unpaired electrons, which include superoxide anion radicals, h...

Generation of reactive oxygen species plays a pivotal role in the development of cardiovascular diseases. The present study describes the effects of the methanolic extract of Phoebe grandis (MPG) stem bark on reactive oxygen species-induced endothelial dysfunction in vitro. Endothelium-dependent (acetylcholine, ACh) and -independent relaxation (sodium nitroprusside, SNP) was investigated from i...

Carotenoid lutein was evaluated for its antioxidant potential both in vitro and in vivo. Lutein was found to scavenge superoxide radicals, hydroxyl radicals and inhibited in vitro lipid peroxidation. Concentrations needed for 50% inhibition (IC50) were 21, 1.75 and 2.2 microg/mL respectively. It scavenged 2,2-diphenyl-1-picryl hydrazyl (IC50 35 microg/mL) and nitric oxide radicals (IC50 3.8 mic...

Oxygen-derived free radicals and other oxidizing species are thought to be involved in inflammation and ischemic tissue injuries. Recently, oxygen-derived free radicals also have been implicated in tissue injury of the myocardium subjected to ischemia/reperfusion. The purpose of this investigation was to determine if electrolysis of a physiological buffer would serve as a source of free radical...

The coronary vasodilator effect of bradykinin (BK) in the rat is independent of NO but dependent on activation of phospholipases with involvement of cytochrome P450 mono-oxygenase (P450) and stimulation of Ca++-activated K+ channels, implicating an unidentified hyperpolarizing factor generated via P450 metabolism of arachidonic acid (AA). Because P450 activity also generates free radicals, such...