Antifungal compounds from the rhizome and roots of Ferula hermonis.

The antifungal activity of hexane, dichloromethane, methanol and aqueous extracts from the rhizome and root of Ferula hermonis was assayed in vitro by the agar disk diffusion method against a panel of human opportunistic and pathogenic fungi. Among them, the hexane and dichloromethane extracts showed the highest activity particularly against the dermatophytes Microsporum gypseum and Tricophyton mentagrophytes as well as the yeast Candida lactis-condensi. Activity-guided fractionation of both extracts using an agar overlay bioautographic method led to the isolation of two antifungal compounds which were identified as the daucane aryl esters jaeschkeanadiol p-hydroxybenzoate (ferutinin) and jaeschkeanadiol benzoate (teferidin). Determination of minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) values of both compounds evidenced a stronger antifungal activity for ferutinin than for teferidin. Particularly, T. mentagrophytes was the most sensitive strain with MIC and MFC values ranging from 8 to 256 µg/mL.

Composition and antifungal activity of the essential oil from the rhizome and roots of Ferula hermonis.

The analysis of the essential oil from rhizome and roots of Ferula hermonis Boiss. (Apiaceae) by GC-FID, GC-MS and ¹³C NMR allowed the identification of 79 constituents, more than 90% of the oil, the major one being α-pinene (43.3%), followed by α-bisabolol (11.1%) and the unusual acetylenic compound 3,5-nonadiyne (4.4%). The antifungal activity of the essential oil before and after fractionation was assayed against several yeasts and filamentous fungi. Purification of the active fractions afforded 3,5-nonadiyne, α-bisabolol, jaeschkeanadiol angelate, α-bisabolol oxide B and trans-verbenol, as well as two purified fractions, one of them (JB73) with 73% of jaeschkeanadiol benzoate and the other with 50% of spathulenol. Determination of MIC and MFC values of all these products evidenced strong antifungal activities for JB73 and 3,5-nonadiyne. Particularly, against the dermatophyte Tricophyton mentagrophytes, MIC and MFC values were 0.25 µg/ml for JB73, and 8 µg/ml for 3,5-nonadiyne, the former being more active than amphotericin B and nystatin.

Psilostachyin C: a natural compound with trypanocidal activity.

In this study, the antiprotozoal activity of the sesquiterpene lactone psilostachyin C was investigated. This natural compound was isolated from Ambrosia scabra by bioassay-guided fractionation and was identified by spectroscopic techniques. Psilostachyin C exerted in vitro trypanocidal activity against Trypanosoma cruzi epimastigotes, trypomastigotes and amastigotes, with 50% inhibitory concentration (IC(50)) values of 0.6, 3.5 and 0.9 µg/mL, respectively, and displayed less cytotoxicity against mammalian cells, with a 50% cytotoxic concentration (CC(50)) of 87.5 µg/mL. Interestingly, this compound induced ultrastructural alterations, as seen by transmission electron microscopy, in which vacuolisation and a structural appearance resembling multivesicular bodies were observed even at a concentration as low as 0.2 µg/mL. In an in vivo assay, a significant reduction in the number of circulating parasites was found in T. cruzi-infected mice treated with psilostachyin C for 5 days compared with untreated mice (7.4 ± 1.2 × 10(5)parasites/mL vs. 12.8 ± 2.0 × 10(5)parasites/mL) at the peak of parasitaemia. According to these results, psilostachyin C may be considered a promising template for the design of novel trypanocidal agents. In addition, psilostachyin C inhibited the growth of Leishmania mexicana and Leishmania amazonensis promastigotes (IC(50)=1.2 µg/mL and 1.5 µg/mL, respectively).

Trypanocidal and leishmanicidal activities of sesquiterpene lactones from Ambrosia tenuifolia Sprengel (Asteraceae).

Bioassay-guided fractionation of the organic extract of Ambrosia tenuifolia Sprengel (Asteraceae) led to the isolation of two bioactive sesquiterpene lactones with significant trypanocidal and leishmanicidal activities. By spectroscopic methods ((1)H- and (13)C-nuclear magnetic resonance, distortionless enhancement by polarization transfer, correlated spectroscopy, heteronuclear multiple-quantum coherence, electron impact-mass spectrometry, and infrared spectroscopy), these compounds were identified as psilostachyin and peruvin. Both compounds showed a marked in vitro trypanocidal activity against Trypanosoma cruzi epimastigotes with 50% inhibitory concentration (IC(50)) values of less than 2 microg/ml. Psilostachyin exerted a significant in vitro activity against the trypomastigote forms of T. cruzi (IC(50), 0.76 microg/ml) and was selected for in vivo testing. Psilostachyin-treated mice had a survival of 100% and lower parasitemia values than control mice. Both compounds were also tested on Leishmania sp. promastigotes: psilostachyin (IC(50), 0.12 microg/ml) and peruvin (IC(50), 0.39 microg/ml) exerted significant leishmanicidal activities. This is the first time that the trypanocidal and leishmanicidal activities of these compounds have been reported. The selectivity index (SI) was employed to evaluate the cytotoxic effect of lactones on T lymphocytes. Although the SIs of both compounds were high for T. cruzi epimastigotes, psilostachyin was more selective against trypomastigotes (SI, 33.8) while peruvin showed no specificity for this parasite. Both compounds presented high selectivity for Leishmania spp. The results shown herein suggest that psilostachyin and peruvin could be considered potential candidates for the development of new antiprotozoal agents against Chagas' disease and leishmaniasis.

Antifungal sesquiterpene from the root of Vernonanthura tweedieana.

The bioassay-guided fractionation of the antifungal dichloromethane extract from the roots of Vernonanthura tweedieana (Baker) H. Rob. (Asteraceae), using an agar overlay bioautographic method, allowed the isolation of one active sesquiterpene (1), identified as 6-cinnamoyloxy-1-hydroxyeudesm-4-en-3-one. Minimal inhibitory concentrations (MIC) and minimal fungicidal concentrations (MFC) of 1 showed Trichophyton mentagrophytes as the most sensitive strain, with the same MIC and MFC values (4 microg/ml).