Antibacterial Activity of <i>Bougainvillea Glabra, Eucalyptus Globulus, Gnaphalium Attenuatum</i>, and Propolis Collected in Mexico

Abstract

Bougainvillea glabra C., Eucalyptus globules Labill., and Gnaphalium attenuatum DC., as well as propolis, have been used in Mexican traditional medicine as a remedy to treat respiratory illnesses. There are few biological reports of such material collected in Mexico, despite the high demand for them as raw material for popular and industrial uses. The antibacterial activity of the plants and propolis studied here were evaluated against a panel of bacteria using three different methodologies: agar disc diffusion, macro and micro dilution methods. E. globules and G. attenuatum extracts showed the strongest active values (P > 0.05) in the agar disc diffusion method with a range of 8 - 22 mm inhibition zone, MIC values ranging from 25 - 250g/mL, and MBC values of 25 - 500g/mL obtained by macro and micro dilution methods. B. glabra extracts were active against E. coli , S. typhi, K. pneumoniae, S. aureus and S. agalactiae , with 8 - 13 mm inhibition zone, MICs ranging from 500 - 3000g/mL, and MBCs of 1000 - 3000g/mL. The propolis extract turned out to be active against E. coli, K. pneumoniae, S. aureus and S. agalactiae , with values of 7 - 12 mm, MICs of 1000 - 2000g/mL, and MBCs of 2000 - 2500g/mL. E. globules and G. attenuatum extracts were the most active in the three methodologies assayed. This is also the first time that the antibacterial activity of G. attenuatum has been experimentally demonstrated. The microdilution method showed to be more sensitive, less expensive and minor time-consuming technique compared with the other two.