Antibacterial activity against Streptococcus mutans and stability of the natural products containing extract from Mikania glomerata Sprengel

Abstract

Mikania glomerata Sprengel (Asteraceae), known as guaco, is commonly used as bronchodilator, antiasthmatic, and expectorant, and the effects observed are attributed to coumarin. The aim of the present study was to evaluate the effect of the extracts and formulations (antiseptic solutions and syrup) containing guaco, with or without propolis, against Streptococcus mutans, and the stability of the antiseptic solutions. The antibacterial activity of the extracts and the formulations against S. mutans ATCC 25175 was assessed by agar diffusion, with the same procedure being used to determine the stability of the antiseptic solutions under room temperature and refrigeration (8º - 10ºC) during a period of three months. The extracts containing guaco and propolis and the antiseptic solutions inhibited the growth of S. mutans. After the first month, except for the antiseptic solution with guaco 5%, all of them inhibited the microorganism tested. In the second month, only the antiseptic solution containing propolis produced the bacterial inhibition. In the last month, under room temperature, the solutions with propolis were active and stable. The results showed that the formulations containing guaco, with or without propolis, were active against S. mutans, but could lose stability depending on temperature. However, this report demonstrated that natural products could be an important alternative against oral infections, including tooth decay and dental plaque.