A new Antifungal and Antiprotozoal Depside from the Andean Lichen Protousnea poepigii

GUILLERMO SCHMEDA-HIRSCHMANN; ALEJANDRO TAPIA; BEATRIZ LIMA; MARIANO PERTINO,; MAXIMILIANO SORTINO; SUSANA ZACCHINO; ANTONIETA ROJAS DE ARIAS; GABRIELA EGLY FERESIN

PHYTOTHERAPY RESEARCH

John Wiley & Sons, Ltd. Wiley Intercienscience

Lugar: London UK; Año: 2008 vol. 22 p. 349 - 355

0951-418X

Extracts from the Andean lichens Protousnea poeppigii and Usnea florida displayed antimicrobial activity against the pathogenic fungi Microsporum gypseum, Trichophyton mentagrophytes and T. rubrum with MIC values between 50 and 100 µg/mL. From the active extracts, four main metabolites were isolated and identified as the new depside, isodivaricatic acid, and the known metabolites 5-propylresorcinol, divaricatinic acid and usnic acid. Isodivaricatic acid and divaricatinic acid presented antifungal effect towards M. gypseum with a MIC of 50 µg/mL and against T. mentagrophytes and T. rubrum and with MIC values of 50 and 100 µg/mL, respectively. The new isodivaricatic acid was active towards Leishmania amazonensis, Leishmania brasiliensis and Leishmania infantum promastigotes with 100% lysis at 100 µg/mL. The activity of the new compound decreased on acetylation of the hydroxy groups as well as on methylation of the acid function. The structures were elucidated by spectroscopic means. The spectroscopic data of isodivaricatic acid are presented here for the first time. Copyright © 2007 John Wiley & Sons, Ltd.