Two new cytosporones from the culture of endophytic Phomopsis sp.

Abstract

Two new steroids, (14b,22E)-9,14-dihydroxyergosta-4,7,22-triene-3,6-dione (1) and (5a,6b,15b,22E)-6-ethoxy-5,15-dihydroxyergosta-7,22-dien-3-one (2), together with three known steroids, calvasterols A and B (3 and 4, resp.), and ganodermaside D (5), were isolated from the culture broth of an endophytic fungus Phomopsis sp. isolated from Aconitum carmichaeli. The structures of these compounds were elucidated on the basis of spectroscopic analysis, and their inhibitory activities against six pathogenic fungi were evaluated. Most of the compounds showed moderate or weak antifungal activities in a brothmicrodilution assay.Introduction. -Endophytic fungi of the genus Phomopsis are a rich source of bioactive secondary metabolites with diverse structures [1] [2]. In the course of our studies on chemical constituents of the endophytic fungi of medicinal plants, several new compounds had been obtained previously [3 -5], including two new tenmembered lactones from a Phomopsis strain. During our ongoing research on endophytic fungi, one strain of Phomopsis sp. was isolated from the traditional Chinese medicinal plant Aconitum carmichaeli Debx. The AcOEt extract of the culture broth of this strain showed potent antifungal activity. A follow-up fractionation led to the isolation of two new steroids, (14b,22E)-9,14-dihydroxyergosta-4,7,22-triene-3,6-dione (1) and (5a,6b,15b,22E)-6-ethoxy-5,15-dihydroxyergosta-7,22-dien-3-one (2), together with three known steroids, calvasterols A and B (3 and 4, resp.), and ganodermaside D (5). Several articles on chemical constituents, pharmaceutical uses, and toxicities of the Aconitum plants had been reported previously. However, few work has been conducted on the endophytic fungi of the plant. Here, we report the isolation and structure elucidation of the new compounds, as well as their antifungal activities. We describe the secondary metabolites from an endophytic fungi of the plant A. carmichaeli for the first time.

A cultured endophyte community is associated with the plant Clerodendrum inerme and antifungal activity

“…Fu (2011) isolated antifungal metabolites from Phomopsis sp By254, an endophytic fungus in Gossypium hirsutum, and identified them as epoxycytochalasin H (1), cytochalasin N (2), and cytochalasin H (3). According to Wu et al (2013), 2 new steroids and 3 known steroids were isolated from the culture broth of the endophytic fungus Phomopsis sp, which was isolated from Aconitum carmichaelii. Most of these compounds showed moderate or weak antifungal activities in a broth-microdilution assay.…”

Bioactive Secondary Metabolites of the Genus Diaporthe and Anamorph Phomopsis from Terrestrial and Marine Habitats and Endophytes: 2010–2019

“…The fungus Phomopsis sp. IFB-ZS1-S4 isolated from Scaevola hainanensis Hance extracted a known pestalotiopsone F ( 40 ), which showed moderate inhibition on neuraminidase in vitro with IC 50 value of 9.90 ± 0.42 μM [ 37 ]. Cultivation of Phomopsis sp.…”

“…The endophytic fungus Phomopsis sp. IFB-ZS1-S4 provided a known aspergillide C ( 222 ), which had moderate inhibitory effect on neuraminidase in vitro with IC 50 value of 5.59 μM [ 37 ]. Four highly oxygenated tenellone-macrolide conjugated dimers, lithocarpins A-D ( 223 – 226 ), were obtained from P .…”

Biosynthesis of Cytosporones in Leotiomycetous Filamentous Fungi

“…CS-52−56 and C. cassiicola JCM 23.3 (Figure 1), as well as other endophytic fungi. 15,19,38,39 We also detected the production of small amounts of cytosporone B (5) in our yeast heterologous production systems. Supplementation of the medium with 0.5 mM to 1.0 mM Cu 2+ promoted the formation of this congener for an unknown reason (SI Figure S18).…”