Antifungal activity of Heterothalamus alienus metabolites

Abstract

The chemical study of Heterothalamus alienus gave rutin, spathulenol (1), (1R,7S)-germacra-4(15),5,10(14)-trien-1beta-ol (2), sakuranetin (3), padmatin 3-acetate (4), (2R,3R)-dihydroquercetin-7,3',4'-trimethyl ether (5), (2R,3R)-dihydroquercetin-7,4'-dimethyl ether (6), (2R,3R)-3-acetoxy-5,7,4'-trihydroxyflavanone (7), as the main components of an antifungal extract of the aerial parts of the plant. Compound 2 showed moderate activity, with Epidermophyton floccosum being the most susceptible species (MIC = 100 microg/mL); compound 3 showed the best antifungal behavior having a broad spectrum of action and the lowest MICs. This flavanone along with flavanolol 5 showed very good activity against standardized (MIC = 31.2 microg/mL) as well as clinical isolates of Trichophyton rubrum and T. mentagrophytes (MIC ranges 31.2-62.5 microg/mL and 31.2-125 microg/mL, respectively) and demonstrated not only fungistatic but also fungicide properties. Flavanolol 6 was active against all the dermatophytes tested with MICs of 62.5-250 microg/mL. Rutin, spathulenol (1) and the 3-acetylated flavanones 4 and 7 were inactive or marginally active against the fungal panel.

Structural Crystalline Characterization of Sakuranetin — An Antimicrobial Flavanone from Twigs of Baccharis retusa (Asteraceae)

“…The antifungal activity of sakuranetin was previously reported against phytopathogenic Cladosporium sp. [22] and against clinical strains of Trichophyton rubrum and T. mentagrophytes [23]. In this work, purified sakuranetin displayed also a good potential as antifungal agents for opportunistic pathogenic yeasts.…”

A Review on Sources and Pharmacological Aspects of Sakuranetin

“…Previously, the antifungal activity of sakuranetin was also observed for the phytopathogenic strain Cladosporium sp. [65] and for the clinical strains Trichophyton rubrum and T. mentagrophytes [66].…”

Value of the ethnomedical information for the discovery of plants with antifungal properties. A survey among seven Latin American countries

“…Plants provide unlimited opportunities for the isolation of new antifungal compounds because of the unmatched availability of chemical diversity (Cos et al, 2006;Maregesi et al, 2008); in fact, numerous antifungal compounds have been isolated from them (Rosemary et al, 1982;Agrawal et al, 2000;Escalante et al, 2002;Danelutte et al, 2003;Malheiros et al, 2005;Stein et al, 2006;Agüero et al, 2007;Pacciaroni et al, 2008). But the first important concern within a program of discovery of new plants with antifungal properties is the selection of species to be submitted to biological evaluation.…”