RESUMO
The aqueous extract of garlic (Allium sativum) and allicin both showed significant in vitro antibacterial activity against isolates of multiple drug-resistant Shigella dysenteriae 1, Sh. flexneri Y, Sh. sonnei and enterotoxigenic Escherichia coli. The minimum inhibitory concentrations of the aqueous extract and allicin against Sh. flexneri Y were 5 and 0.4 microliters/ml, respectively. The two agents also showed promising in vivo antibacterial activity against Sh. flexneri Y when tested in the rabbit model of experimental shigellosis, fully curing the infected rabbits within 3 days. On the contrary, 4 of the 5 rabbits in the control group died within 48 h. The rectal swab of rabbits of the experimental groups became free of the challenge bacteria on the second day of treatment. The antibacterial activity against the challenge strain was observed in the sera of the treated rabbits with 30-60 min of administration of the agents. The LD50 values of the aqueous extract and allicin in mice were 173.78 ml/kg and 204.17 microliters/kg of body weight, respectively. At the therapeutic dose, the two agents did not show any adverse effects on the standard biochemical profile of blood.