Identification of antifungal compounds from the Root Bark of Cordia anisophylla J.S. Mill.

The dichloromethane extract of the root bark of the Panamanian plant Cordia anisophylla J.S. Mill. (Boraginaceae) presented antifungal activity against a susceptible strain of Candida albicans in a bioautography primary screening. The susceptible strain was used to detect minor active compounds that would not have been detected using a classical approach. In order to identify the antimicrobial compounds, the active extract was fractionated by semi-preparative high-performance liquid chromatography and the fractions were submitted to the antifungal bioassay. This procedure enabled a precise localization of the antifungal compounds directly in the chromatogram of the crude extract and allowed for an efficient, targeted isolation. Four compounds were isolated, one of which is a new natural product. The structures were elucidated using spectroscopic methods. Their antifungal properties were evaluated by determination of the minimum inhibitory quantity and concentration by bioautography and dilution assay against a wild type strain of C. albicans

Identification of Triterpenoids from Schefflera systyla, Odontadenia puncticulosa and Conostegia speciosa and In Depth Investigation of Their in vitro and in vivo Antifungal Activities

As a part of a broad screening of antifungal agents from plant origin, crude extracts from Panamanian plants having related types of constituents displayed significant activities in an agar overlay thin layer chromatography assay against a susceptible strain of Candida albicans. These were the methanolic extract of the leaves of Schefflera systyla and Odontadenia puncticulosa and of the stems of Conostegia speciosa, that are species not previously investigated from a phytochemical viewpoint. For all plants, high-performance liquid chromatography (HPLC) antifungal activity based profiling allowed the rapid localization of antifungal agents that were further obtained by targeted isolation procedure by semi-preparative HPLC or medium pressure liquid chromatography (MPLC) after LC gradient transfer. Different hederagenin saponins and one aglycone were found to be responsible for the antifungal activities of the extracts. Alpha-hederin was the antifungal of S. systyla, pulsatilla saponin D and 3 eta-O-[beta-D-xylopyranosyl-(1 -> 3)-alpha-L-rhamnopyranosyl-(1. 2)-[beta-D-glucopyranosyl-(1 -> 4)]-alpha-L-arabinopyranosylhederagenin of O. puncticulosa and arjunolic acid of C. speciosa. Their minimal inhibitory concentration (MIC) against planktonic and biofilm cells of C. albicans were determined. Alpha-hederin was the most potent compound with a MIC of 4 mu g mL(-1). Structurally related compounds (hederagenin, medicagenic acid 3-O-beta-D-glucopyranoside and medicagenic acid) were used as standards and tested for comparison purposes. In order to better estimate the potential of these triterpenoids as antifungal agents, their cytological effects on C. albicans were determined by transmission electron microscopy (TEM) and the in vivo activity of alpha-hederin, medicagenic acid 3-O-beta-D-glucopyranoside and medicagenic acid was evaluated for the first time in the Galleria mellonella larvae model

Anti-<i>Candida</i> Cassane-Type Diterpenoids from the Root Bark of <i>Swartzia simplex</i>

A dichloromethane extract of the roots from the Panamanian plant <i>Swartzia simplex</i> exhibited a strong antifungal activity in a bioautography assay against a genetically modified hypersusceptible strain of <i>Candida albicans</i>. At-line HPLC activity based profiling of the crude extract enabled a precise localization of the antifungal compounds, and dereplication by UHPLC-HRESIMS indicated the presence of potentially new metabolites. Transposition of the HPLC reversed-phase analytical conditions to medium-pressure liquid chromatography (MPLC) allowed an efficient isolation of the major constituents. Minor compounds of interest were isolated from the MPLC fractions using semipreparative HPLC. Using this strategy, 14 diterpenes (<b>1</b>–<b>14</b>) were isolated, with seven (<b>5</b>–<b>10</b>, <b>14</b>) being new antifungal natural products. The new structures were elucidated using NMR spectroscopy and HRESIMS analysis. The absolute configurations of some of the compounds were elucidated by electronic circular dichroism spectroscopy. The antifungal properties of these compounds were evaluated as their minimum inhibitory concentrations in a dilution assay against both hypersusceptible and wild-type strains of <i>C. albicans</i> and by assessment of their antibiofilm activities. The potential cytological effects on the ultrastructure of <i>C. albicans</i> of the antifungal compounds isolated were evaluated on thin sections by transmission electron microscopy