A new antifungal and antiprotozoal depside from the Andean lichen Protousnea poeppigii.
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 microg/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 microg/mL and against T. mentagrophytes and T. rubrum and with MIC values of 50 and 100 microg/mL, respectively. The new isodivaricatic acid was active towards Leishmania amazonensis, Leishmania brasiliensis and Leishmania infantum promastigotes with 100% lysis at 100 microg/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.
Laboratorio de Química de Productos Naturales, Instituto de Química de Recursos Naturales, Universidad de Talca, Casilla 747, Talca, Chile. schmeda@utalca.cl
Guillermo
G
Schmeda-Hirschmann
Alejandro
A
Tapia
Beatriz
B
Lima
Mariano
M
Pertino
Maximiliano
M
Sortino
Susana
S
Zacchino
Antonieta Rojas de
AR
Arias
Gabriela Egly
GE
Feresin
D000818:Animals; D000890:Anti-Infective Agents / Q000737:chemistry / Q000302:isolation & purification / Q000494:pharmacology*; D001203:Ascomycota / Q000737:chemistry; D001419:Bacteria / Q000187:drug effects*; D053630:Depsides / Q000737:chemistry / Q000494:pharmacology*; D004353:Drug Evaluation, Preclinical / Q000379:methods; D007891:Leishmania / Q000187:drug effects*; D008011:Lichens / Q000737:chemistry*; D009682:Magnetic Resonance Spectroscopy; D008826:Microbial Sensitivity Tests; D003904:Mitosporic Fungi / Q000187:drug effects*; D012459:Salicylates / Q000494:pharmacology; D020949:Usnea / Q000737:chemistry
D000890:Anti-Infective Agents; D053630:Depsides; D012459:Salicylates; C533494:isodivaricatic acid