In vitro determination of the antimicrobial potential of homemade preparations based on medicinal plants used to treat infectious diseases

Abstract

The majority of the population in developing countries uses plants or plant preparations in their basic health care. Many plant species used nowadays in folk medicine have been proved to have antimicrobial properties. However, several factors, such as incorrect preparation of the plants, can interfere with the effectiveness of the treatment. The purpose of this study was to assess the use of homemade preparations of medicinal plants in the treatment of infectious diseases, by in vitro determination of their antimicrobial potential. Based on recipes elicited by questionnaires that were previously applied to a participant population, the samples were prepared in a similar manner and analyzed by the agar diffusion method. Members of 41 families, whose children attend a center of education that serves several needy communities in the city of Fortaleza (Ceará, Brazil), were interviewed; of these, 97.6% said they had used herbal therapy as a means to treat infectious diseases. In replies to a total of 39 questionnaires, 97 different homemade preparations of medicinal plants were cited. Out of 45 samples subjected to an in vitro assessment of antimicrobial activity, 25 (55.6%) had some inhibitory effect on the growth of at least one of the microorganisms used. Most of the plants with known antimicrobial properties and cited by respondents showed variations in their in vitro activity, according to the manner in which they were prepared.