Abstract
Seven previously unreported cyclonerane derivatives, namely, 3,7,11-trihydroxycycloneran-10-one, cycloneran-3,7,10,11-tetraol, cycloneran-3,7,11-triol, 11,12,15-trinorcycloneran-3,7,10-triol, 7,10S-epoxycycloneran-3,15-diol, 7,10R-epoxycycloneran-3,15-diol, and (10Z)-15-acetoxy-10-cycloneren-3,7-diol, were isolated in addition to the known (10Z)-cyclonerotriol, (10E)-cyclonerotriol, catenioblin C, and chokol E from the culture of Trichoderma asperellum A-YMD-9-2, an endophytic fungus obtained from the marine red alga Gracilaria verrucosa. The structures of previously unreported compounds were established by spectroscopic techniques, including 1D/2D NMR, MS, and IR. The isolation of these new cyclonerane derivatives greatly adds to the structural diversity of unusual cyclonerane sesquiterpenes, and several isolates exhibit potent inhibition against some marine phytoplankton species.
Highlights
Trichoderma species have proven to be prolific sources of diterpenes and sesquiterpenes, especially some unusual terpene skeletons, such as harziane, proharziane, wickerane, citrinovirin, trichaspin, and cyclonerane [1,2,3,4,5,6,7,8]
30 cyclonerane sesquiterpenes have been characterized, and almost half of them occurred in Trichoderma species
Its 13 C NMR spectrum (Table 2) showed a close similarity to that of 2, except for the lack of the signal for an oxymethine group and the presence of the signal for a methylene group of C-10, which was supported by its HMBC correlations to H3 -12 and/or H3 -15
Summary
Trichoderma species have proven to be prolific sources of diterpenes and sesquiterpenes, especially some unusual terpene skeletons, such as harziane, proharziane, wickerane, citrinovirin, trichaspin, and cyclonerane [1,2,3,4,5,6,7,8]. Of the cyclonerane-type sesquiterpenes, cyclonerodiol and its analogs have been isolated from several species of Trichoderma [4,5,6,9,10,11,12,13,14]. 30 cyclonerane sesquiterpenes have been characterized, and almost half of them occurred in Trichoderma species. In our ongoing search for new and bioactive metabolites from marine algicolous fungi [15], an endophytic strain (A-YMD-9-2) of Trichoderma asperellum, isolated from the marine red alga Gracilaria verrucosa, was chemically examined.
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
