Evaluation of the stimulatory and inhibitory effects of Malva sylvestris leaf extract on some beneficial and pathogenic bacteria from the colon

Abstract

The aim of the present study was to evaluate the stimulatory and inhibitory effects of Malva sylvestris leaf extract on some selected beneficial and pathogenic bacteria from the colon to form a presupposition on its efficacy on intestinal health. The sensitivity of colon bacterial strains to M. sylvestris leaf extract was tested by a broth dilution method in the anaerobic cabinet. Malva sylvestris leaf extract stimulated the growth of Bifidobacterium bifidum from beneficial species starting from 0.06 mg/mL dose (P<0.05). The same stimulatory effect was observed for other beneficial species Bifidobacterium infantis and Lactobacillus acidophilus from 0.125 mg/mL dose (P<0.05) and that effect was more obvious for B. infantis. On the other hand, the extract did not have any effect on Lactobacillus casei up to 4 mg/mL dose. Malva sylvestris leaf extract also had a potential inhibitory activity against pathogenic Escherichia coli , Clostridium perfringens , and Staphylococcus aureus from 0.25, 2, and 4 mg/mL concentrations respectively (P<0.05). The dose of 8 mg/mL of the extract (MIC; minimal inhibitory concentration) completely inhibited Fusobacterium nucleatum (P<0.05), other enteropathogen, which is associated with colorectal cancer. It was concluded that M. sylvestris leaf extract at 0.06-8 mg/mL dose could have favorable effects on colon bacteria since the extract selectively promoted the most of the beneficial species’ growth at this dose range while it had a potential inhibitory or inhibitory effect on pathogenic ones. Investigating the effects of M. sylvestris leaf extract on other colon bacteria and testing the in vivo effectiveness will contribute to a better understanding of its efficacy on colon microbiota and intestinal health.