Chemical and pharmacological evaluation of Hypericum perforatum extracts.
Bibliographic record
Abstract
AIM: To determine the concentrations of chemical characteristic to extracts of leaves and flowers of Hypericum perforatum (St John's wort) in a number of selected samples and, following chemical characterization, to investigate the effects of these extracts on several pharmacological properties including effects of the extracts on inhibition of 5-hydroxytryptamine (5-HT) uptake and on antioxidant properties. METHODS: The samples were analyzed for the presence of characteristic chemicals by high performance liquid chromatography (HPLC) directly coupled to ultraviolet wavelength absorbance and positive or negative mode electrospray mass spectrometric detection. The effects of extracts on 5-HT uptake were determined by quantifying 3H-5-HT incorporation into rat hippocampal prisms. Estimates of effects of extracts on free radical scavenging capacity were made using a dynamic assay based on the ability of compounds to prevent the initiation of a colored reaction produced by the horseradish peroxidase catalyzed formation of hydroxyl free radicals from hydrogen peroxide using 2',2'-azinobis (3-ethylbenzthiazoline-6-sulfonic acid) as the color indicator. RESULTS: The chemical profile of a number of extracts were determined and found to differ substantially from each other. Inhibition of 5-HT uptake was found to correlate with hyperforin content and free radical scavenging capacity was found to correlate with the content of several flavonoids including quercetin and hyperoside. CONCLUSION: Standardized extracts of H perforatum varied substantially in the concentration of several characteristic chemicals. The correlation between pharmacological activity and certain characteristic chemicals found in these extracts indicates that the medicinal benefit derived from selected extracts will vary considerably depending on their chemical composition.
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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 | 0.001 | 0.000 |
| Meta-epidemiology (narrow) | 0.000 | 0.000 |
| Meta-epidemiology (broad) | 0.000 | 0.000 |
| Bibliometrics | 0.000 | 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 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".