Novel Antibacterial, Antifungal and Antiparasitic Activities of <i>Quassia amara</i> Wood Extract

Abstract

Quassia amara is a plant of the family Simaroubaceae of Northern Brazilian origin.Its use in folk medicine is widespread, especially as an antiparasitic, antifungal and antibacterial agent. Our purpose was testing a Quassia amara ethanol wood extract (QWE) on various parasites, fungi and bacteria which had not been previously screened for this ingredient. QWE was found to have a strong antiparasitic effect on Demodex spp by counting the number of mites extracted from biopsies of pustules of patients with erythematotelangiectatic and papulopustular subtypes of rosacea along a topical treatment with 4% QWE, these numbers reaching their physiological value after a 42-day course.In Vitrotesting of this extract on cultures of Trichomonas vaginalis collected from symptomatic patients showed a rapid inhibition of the growth of the trophozoites after 48 hours of contact. QWE also showed a marked antifungal activity on Candida spp (namely C. albicans, C. parapsilosis, C. glabrata and C. krusei, the latest at a lesser extent, and Malassezia furfur isolated from samples of infected patients, inhibiting the growth of fungi in both a time- and dose-dependent manner.The antibacterial activity of QWE was demonstrated in cultures of P. acnes and coagulase- positive Staphylococci where the growth of the bacteria was reduced in a significant manner (p<0.05) and at a lesser extent in cultures of coagulase-negative Staphylococci where the growth inhibition was not statistically significant. Contrarily, QWE had no effect on the growth of Chlamydia trachomatis, but uniquely altered the morphology and quantity of chlamydial inclusions.To the best of our knowledge, this is the first time that QWE is shown to have antiparasitic activity on Trichomonas vaginalis and Demodex spp, an antifungal activity on Malassezia furfur and Candida spp and an antibacterial activity on P. acnes