The radical scavenging ability of garlic examined in various models.

The influence of an intake of garlic powder (1% added to a standard chow for an 8 week period) on the susceptibility to ventricular arrhythmias under radical reperfusion was investigated in the isolated rat heart perfused with a modified Krebs-Henseleit solution and the generating system hypoxanthine/xanthine oxidase. The incidence of ventricular fibrillation (VF) after the reopening of the LAD was significantly reduced in the garlic group as compared to the untreated controls (VF: 50% vs 89%). As this protective effect might relate to radical scavenging capacities, two in vitro radical generating test systems were chosen where the garlic activity could be determined. Dose-dependently, garlic was able to capture the radicals. Interestingly, only the garlic extract, was active. The ethanol extract hardly showed any radical scavenging ability. According to this result, we concluded that an intact alliin-alliinase system is important for the activity of garlic. Further investigations were done with different tissues under oxidative stress conditions. The kinetics of each organ, were measured chemiluminometrically. Especially liver and kidney of garlic fed rats showed inhibiting effects. Finally, an attempt was made to relate these radical scavenging and lipidperoxidation inhibiting effects to respective garlic compounds. Two substances, allylmercaptane and diallyldisulfide, were proposed.