NMR spectroscopicsearch module for Spektraris an online resource for plant natural product identification – taxane diterpenoids from Taxus × media cell suspension cultures as a case study

摘要

Development and testing of Spektraris-NMR an online spectral resource, is reported for the NMR-based structural identification of plant natural products (PNPs). Spektraris-NMRallows users to search with multiple spectra at once and returns a table with alist of hits arranged according to the goodness of fit between query data and database entries. For each hit, a link to a tabulated alignment of ¹H-NMR and ¹³C-NMR spectroscopic peaks (query versus database entry) is provided. Furthermore, full spectroscopic records and experimental meta information about each database entry can be accessed online. To test the utility of Spektraris-NMR for PNP identification, the database was populated with NMR data (total of 466 spectra) for ∼250 taxanes, which are structurally complex diterpenoids (including the anticancer drug taxol) commonly found in the genus Taxus. NMR data generated used was then generated with metabolites purified from Taxus cell suspension cultures to search Spektraris-NMR, and were able to identify eight taxanes with high confidence. A ninth isolated metabolite could be assigned, based on spectral searches, to a taxane skeletal class, but no high confidence hit was produced. Using various spectroscopic methods, this metabolite was characterized as the taxane 2-deacetylbaccatin IV, a novel taxane. These results indicate that Spektraris-NMR is a valuable resource for rapid and reliable identification of known metabolites and has the potential to contribute to de-replication efforts in the search for novel PNPs.