The antifungal properties of terpenoids from the endophytic fungus Bipolaris eleusines

Abstract

A series of terpenoids (1–17), comprising six new compounds designated bipolariterpenes A-F (1–6) and eleven recognized compounds (7–17), were isolated from the wheat culture of the potato endophytic fungus Bipolariseleusines. Their structures and stereochemistry were clarified by HRESIMS, NMR, DP4 + probability analyses, and computations for electronic circular dichroism (ECD). All compounds are made up of six meroterpenoids, four sesterterpenes and seven sesquiterpenes. Among them, four sesterterpenes (4, 5, 10, 11) were investigated for their antifungal, antibacterial and cytotoxic properties, and six meroterpenoids (1–3, 7–9) were evaluated for their antifungal properties. The compounds 7, 9, and 10 had substantial antifungal activity against Epidermophytonfloccosum at a concentration of 100 µM. No antibacterial and cytotoxic activities were observed. Graphical Abstract

Endophytic Fungi from the Four Staple Crops and Their Secondary Metabolites

“…Sixteen sativene-type sesquiterpenoids ( 54 – 69 ) ( Figure 3 ) as well as three seco-longifolene sesquiterpenoids ( 70 – 72 ) and one sesquiterpene dimer ( 73 ) were obtained from cultures of the potato endophytic fungus B. eleusines . Among them, compounds 61 and 63 inhibited LPS-induced nitric oxide production in RAW264.7 macrophages with IC 50 values of 23.8 and 17.5 μM, respectively, while none of the other compounds showed significant biological activity [ 100 , 101 , 102 ]. Eighteen trichothecene sesquiterpenoids, trichothecrotocins A–B ( 74 – 75 ) ( Figure 3 ), trichothecrotocins K–S ( 88 – 89 , 76 – 82 ) and compounds 83 – 87 , 90 – 91 were obtained from the liquid ferment of the potato endophyte fungus Trichothecium crotocinigenum [ 103 ].…”