Effect of garlic (Allium sativum) on Salmonella typhi infection, gastrointestinal flora and hematological parameters of albino rats

Abstract

The effect of consumption of garlic (Allium sativum) in treating Salmonella typhi infection and on the gastrointestinal flora and hematological parameters of rats was investigated. Crude garlic extract inhibited the growth of S. typhi on agar plate with a zone of inhibition averaging 23.8 mm in diameter using the agar diffusion assay. This inhibition was superior to that of all the conventional antibiotics used except streptomycin which gave a growth inhibitory value of 24.0 mm. In the in vivo assay, although, pretreatment with the extract did not protect rats orogastrically dosed with the infective dose of S. typhi from the infection, the consumption of crude garlic extract however, caused a significant (p<0.05) reduction in the number of S. typhi in the feaces of the infected rats from 2.0 x 10⁸ to 9.0 x 10¹ cfu/ml and also reduced the duration of infection from 5 to 3 days. On the effect of consumption of garlic extract on the type and load of gastrointestinal flora and hematological parameters of rats, garlic extract caused a significant (p<0.05) reduction in the type of bacteria present in the gastrointestinal tract of rats fed 1 ml daily for 7 weeks from six microbial types to one microbial species, reduction in microbial load of the flora from 1.64 x 10¹² to 1.3 x 10⁷ cfu/ml, reduction in packed cell volume (PCV), total white blood cells (WBC) and lymphocytes counts but caused an increase in neutrophils and monocytes counts of the rats. The observed increases in the neutrophils and monocytes counts of the blood suggested that garlic may possess immune-stimulatory effect in addition to its antibacterial effect.

Key words: Salmonella typhi, Allium sativum, antibacterial activity, rats.