UPLC-Q-TOF-MS/MS Analysis of -Sativene Sesquiterpenoids to Detect New and Bioactive Analogues From Plant Pathogen .

-sativene sesquiterpenoids are an important member of phytotoxins and plant growth regulators isolated from a narrow spectrum of fungi. In this report, eight -sativene sesquiterpenoids (-) were first analyzed using the UPLC-Q-TOF-MS/MS technique in positive mode, from which their mass fragmentation pathways were suggested. McLafferty rearrangement, 1,3-rearrangement, and neutral losses were considered to be the main fragmentation patterns for the [M+1] ions of -. According to the structural features (of different substitutes at C-1, C-2, and C-13) in compounds -, five subtypes (A-E) of -sativene were suggested, from which subtypes A, B/D, and E possessed the diagnostic daughter ions at / 175, 189, and 203, respectively, whereas subtype C had the characteristic daughter ion at / 187 in the UPLC-Q-TOF-MS/MS profiles. Based on the fragmentation patterns of -, several known compounds (-) and two new analogues ( and ) were detected in the extract of plant pathogen fungus based on UPLC-Q-TOF-MS/MS analysis, of which , , , and were then isolated and elucidated by NMR spectra. The UPLC-Q-TOF-MS/MS spectra of these two new compounds ( and ) were consistent with the fragmentation mechanisms of -. Compound displayed moderate antioxidant activities with IC of 0.90 and 1.97 mM for DPPH and ABTS scavenging capacity, respectively. The results demonstrated that -sativene sesquiterpenoids with the same subtypes possessed the same diagnostic daughter ions in the UPLC-Q-TOF-MS/MS profiles, which could contribute to structural characterization of -sativene sesquiterpenoids. Our results also further supported that UPLC-Q-TOF-MS/MS is a powerful and sensitive tool for dereplication and detection of new analogues from crude extracts of different biological origins.