Inhibitory activity of Conyza bonariensis (L.) Cronquist tincture against fungi and bacteria causing superficial infections

MUSSIN, JAVIER; MANZANO, PATRICIA; MANGIATERRA, MAGDALENA; GIUSIANO, GUSTAVO

Revista Cubana de Plantas Medicinales

Editorial Ciencias Médicas

Año: 2017 vol. 22

1028-4796

Introduction: Conyza bonariensis (L.) Cronquist is a worldwide distributed herbaceous plant forming part of the weeds group. In traditional medicine, it is used to treat various skin conditions. Objective: To evaluate the in vitro inhibitory activity of the tincture of C. bonariensis leaves against fungi and bacteria causing superficial infections. Materials and methods: The tincture was obtained by alcoholic maceration of C. bonariensis dry leaves. The minimum inhibitory concentration (MIC) of the tincture was determined against 53 isolates from patients with superficial lesions and 6 reference strains; 20 Malassezia (7 M. sympodialis, 7 M. furfur, 6 M. globosa), 16 Candida (8 C. albicans, 8 C. parapsilosis), 17 dermatophytes (6 Trichophyton rubrum, 6 Trichophyton mentagrophytes, 5 Microsporum canis) and 6 Staphylococcus aureus. Results: At low concentration of C. bonariensis tincture strong reduction of viability of most microorganisms evaluated was obtained (less than 10% v/v). Conclusions: The results allowed us to conclude that C. bonariensis tincture has antibacterial activity against Staphylococcus aureus and antifungal activity against the main fungi causing superficial infections, such as dermatophytes, Candida and Malassezia. MICs variations were observed intergenus and interspecies, but no MICs variations were observed among intraspecies isolates. These results contribute to the scientific explanation of the empirical use of C. bonariensis extract in treating several skin infections and with the revaluation of the traditional ethnomedical knowledge.