Combined analysis of <i>Xylopia rubescens</i> Oliv. leaf oil using gas chromatography with flame ionization detection, gas chromatography with mass spectrometry and <sup>13</sup>C nuclear magnetic resonance: structure elucidation of new compounds
Bibliographic record
Abstract
ABSTRACT Phytochemicals have been isolated from extracts of various Xylopia species (Annonaceae) growing wild in the African rainforest. In contrast, no phytochemical investigations have been reported to date on Xylopia rubescens Oliv. The aim of the present work was to describe the composition of X. rubescens leaf oil. Analysis of the leaf oil has been undertaken by a combination of chromatographic and spectroscopic techniques. Three new compounds have been isolated and their structures elucidated as furanoguaia‐1,4‐diene, furanoguaia‐1,3‐diene and (8Z,11Z,14Z)‐8,11,14‐heptadecatrien‐2‐ol. One other compound is reported for the first time as a natural compound. The oil composition was dominated by both furanoguaiadienes (34.2% and 11.4%, respectively) and by (8Z,11Z,14Z)‐8,11,14‐heptadecatrien‐2‐one (12.8%). The composition of X. rubescens leaf oil varied dramatically from those of the essential oils isolated from other Xylopia species. Copyright © 2013 John Wiley & Sons, Ltd.
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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) | 0.000 | 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 | 0.000 |
| 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".