Evaluation of antibacterial activity of medicinal plants in popular medicine: Alternanthera brasiliana (penicillin), Plantago major (broadleaf plantain), Arctostaphylos uva-ursi (bearberry), and Phyllanthus niruri (stone breaker)

Abstract

Studies of substances obtained from vegetables have been acquiring new perspectives, due to problems associated with the treatment of several infections, mainly about the resistance to antimicrobials.

OBJECTIVES:

To evaluate the antibacterial activity of medicinal plants against different species of bacteria, as well as to analyze their chromatographic profiles.

MATERIALS AND METHODS:

Hydroalcoholic extract and dichloromethane, ethyl acetate, n-butanol, and aqueous fractions were obtained from Alternanthera brasiliana, Plantago major, Arctostaphylos uva-ursi, and Phyllanthus niruri, which were tested by the broth microdilution method using strains of Mycoplasma genitalium, Mycoplasma hominis, Ureaplasma urealyticum, Escherichia coli, Staphylococcus aureus, Staphylococcus saprophyticus, Proteus mirabilis, and Klebsiella pneumoniae. Thus, the minimum inhibitory concentration (MIC) of those samples was determined. The chromatographic profile of the extracts and fractions was determined by thin layer chromatography technique.

RESULTS:

The ethyl acetate fraction of A. uva-ursi presented MIC of 125 µg/mL against M. genitalium and 31.25 µg/mL against S. aureus, the latter has been an excellent antibacterial activity. For the same fraction, P. niruri showed moderate antibacterial activity, with MIC of 250 µg/mL against M. genitalium and S. aureus. The species A. brasiliana and P. major showed little or no activity against the tested strains.

CONCLUSION:

It was not possible to determine a close link between popular medicine, in vitro antibacterial activity, and the phytochemical profile of plants, since the antibacterial effects of the studied plant species have varied compared to different bacteria with and without cell walls.