Copaiba oil and its constituent copalic acid as chemotherapeutic agents against dermatophytes

Abstract

Copaiba oil, an oleoresin extracted from Copaifera genus, has been widely used in popular medicine for the treatment of several diseases. The aim of this study was to investigate the antifungal activity of the copaiba oil and its isolated compounds caryophyllene oxide, copalic acid and acetoxycopalic acid against Trichophyton rubrum, Trichophyton mentagrophytes and Microsporum gypseum strains, using microdilution method and microscopy techniques. It was found that the copaiba oil and the copalic acid were active against dermatophytes by minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) tests. The MIC and MFC of copaiba oil against T. rubrum, T. mentagrophytes and M. gypseum were 125 μg mL-1 (250 μg mL-1), 500 μg mL-1 (500 μg mL-1) and 250 μg mL-1 (250 μg mL-1), respectively. For copalic acid, the MIC and MFC were 50 μg mL-1 (100 μg mL-1), 100 μg mL-1 (100 μg mL-1) and 50 μg mL-1 (100 μg mL-1), respectively. Fluorescence microscopy and scanning electronic microscopy were used to investigate inhibition on hyphal growth by compounds, copaiba oil and copalic acid, showing a strong inhibition and an irregular growth pattern. Cell wall, cytoplasmic membrane and intracellular contents were also damaged. In conclusion, copaiba oil and copalic acid showed great activity against dermatophytes, being potential compounds for the development of antifungal drugs.