Changes in caffeic acid derivatives, alkamides/polyacetylenes and phenylalanine ammonia-lyase (PAL) activity in three Echinacea species in response to salinity stress
Bibliographic record
Abstract
Echinacea is a native North American medicinal plant widely used as a non-specific stimulant for the immune system [1]. Three species of Echinacea (E. purpurea, E. pallida and E. angustifolia) were exposed to 50, 75 and 100 mM NaCl under a hydroponic system to test the hypothesis that salinity stress will cause qualitative and quantitative changes in caffeic acid derivatives, alkamides/polyacetylenes, as well as the activity of phenylalanine ammonia-lyase. Hydrophilic and lipophilic compounds were extracted from the roots by Accelerated Solvent Extractor (ASE) then analysed simultaneously by HPLC. Cichoric acid was the main phenolic compound in E. purpurea (35.1mg g-1 dry weight), whereas echinacoside was the major phenolic in E. pallida and E. angustifolia (11.8 and 7.5mg g-1 dry weight, respectively). The lipophilic fraction contained mainly alkamide 8/9 in E. purpurea and E. angustifolia, while in E. pallida it was ketone 22 [2]. Low salinity stress increased caftaric acid and cynarin content in E. purpurea, and chlorogenic acid, caffeic acid, cynarin and alkamide 8/9 in E. angustifolia. However, high salinity stress diminished the content of cichoric acid, alkamides 2 and 8/9 in E. purpurea as well as echinacoside in E. angustifolia. In E. pallida, moderate and high salt concentrations significantly increased cichoric acid and ketones 20 and 21. HPLC-based assay of PAL activity revealed no significant changes in salt-stressed E. pallida or E. angustifolia, while in E. purpurea, the highest salt concentration significantly increased PAL's specific activity. These changes in marker compounds, in response to salinity stress, will affect the quality of Echinacea products.
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How this classification was reachedexpand
Full frame distilled prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. Learned from the 10,348 direct Codex labels and 10,348 direct Gemma labels. Candidate is the union of thresholded teacher heads; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels or direct frontier model labels.
Codex and Gemma teacher scores by category
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.002 | 0.006 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.001 | 0.000 |
| Bibliometrics | 0.001 | 0.001 |
| 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) | 0.000 | 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 teacher head, 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".