Detection and Partial Structure Elucidation of Basic Taxoids from <i>Taxus wallichiana</i> by Electrospray Ionization Tandem Mass Spectrometry
Bibliographic record
Abstract
A sensitive method for the detection and characterization of basic taxoids from the ethyl acetate extract of Taxus wallichiana has been described. A combined analysis of the fragmentation spectra of 3 purified standard basic taxoids and the substructure analysis of 139 previously reported taxoids provided information on typical primary and secondary product ions that are generated by CID mass spectrometry of basic taxoids. Precursor-scan analysis of selected product ions allowed for the detection of 57 basic taxoids from the ethyl acetate extract of T. wallichiana, 45 of which have not been reported. The method describe in this paper provides a fast method for the "dereplication" of natural products. The mass spectrometric data derived by this method was sufficient for the partial structure elucidation of novel basic taxoids. The method presented in this paper can be easily adapted into a high-throughput screening protocol for the identification and characterization of bioactive natural products.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.000 | 0.000 |
| Meta-epidemiology (narrow) | 0.001 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.001 | 0.000 |
| Science and technology studies | 0.000 | 0.000 |
| Scholarly communication | 0.000 | 0.000 |
| Open science | 0.000 | 0.000 |
| Research integrity | 0.000 | 0.001 |
| Insufficient payload (model declined to judge) | 0.001 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".