Subcutaneous antifungal screening of Latin American plant extracts against Sporothrix schenckii and Fonsecaea pedrosoi

Abstract

Context: Subcutaneous mycoses are chronic infections caused by slow growing environmental fungi. Latin American plants are used in folk medicine to treat these afflictions. Moreover, the potential of the rich Latin American biodiversity for this purpose has not been fully explored.

Objectives: The aim of the study was to screen Latin American plant extracts against two species of subcutaneous fungi: Sporothrix schenckii and Fonsecaea pedrosoi.

Materials and methods: One hundred ninety-five organic extracts from 151 Latin American plants were screened against two subcutaneous fungi by the agar dilution method at a concentration of 100 µg/mL, and minimum inhibitory concentrations (MICs) of active extracts were determined. Positive (amphothericin B) and negative (50% ethanol) controls were used.

Results and discussion: Twenty eight extracts showed activity at ≤100 µg/mL. Of these, four extracts from Gnaphalium gaudichaudianum DC (Asteraceae), Plumeria rubra L (Apocynaceae), Tecoma stans (L.) Juss. ex Kunth. (Bignoniaceae), and Trichostigma octandum (L.), H. Walter showed activity against F. pedrosoi at MIC 12.5 µg/mL; and, four extracts from Bourreria huanita (Lex.) Hemsl. (Boraginaceae), Phytolacca bogotensis Kunth (Phytolaccaceae), Monnina xalapensis Kunth (Polygalaceae) and Crataegus pubescens (C. Presl) C. Presl (Rosaceae) against S. schenckii. This is the first report on antifungal activity of the Latin American plants against these two subcutaneous fungi.

Conclusion: S. schenkii and F. pedrosoi were inhibited by B. huanita (MIC: 12.5 and 25 µg/mL), G. gaudichaudianum (MIC: 50 and 12.5 µg/mL) and T. triflora (MIC: 25 µg/mL).

Keywords::

• Bourreria huanita
• Fonsecaea pedrosoi
• Gnaphalium gaudichaudianum
• Sporothix schenkii
• Terminalia triflora