Identification and characterization of melatonin in medicinal plants : Feverfew, Huang-qin and St. John's Wort
Bibliographic record
Abstract
Medicinal plants are valued for their unique complement of bioactive molecules. However in most medicinal plant species, the bioactive compounds have not been completely characterized and the use of these plants as phytopharmaceuticals is based largely on anecdotal evidence. The principle finding of this study was the discovery of melatonin, a neural hormone secreted by the pineal gland in mammals, in three medicinal plants viz. feverfew, Huang-qin and St. John's wort. 'In vitro' regeneration protocols were developed to minimize the potential for the contamination of the plants with indoleamines produced by fungi or bacteria. Plantlets formed via 'de novo' shoot organogenesis induced on intact seedlings, petiole or etiolated hypocotyl explants in response to thidiazuron supplementation of the culture medium. Histological examination of the cultures revealed that the regenerants were primarily 'de novo' developed shoots in all three species. The most prolific regeneration was observed in cultures of St. John's wort and this species was selected for further analyses. For biochemical characterizations, 2-month-old sterile plantlets were excised from the cultures and exposed to 14C-tryptophan in liquid medium. Radiolabel from 14C-tryptophan was recovered as 14C-indoleacetic acid, 14C-hydroxytryptophan, 14C-serotonin and 14C-melatonin. These data suggested several new possibilities for investigation of the metabolism and function of serotonin and melatonin in plant tissues. These possibilities were investigated with inhibitors of auxin and indoleamine metabolism, viz. 2,3,5-triiodobenzoic acid (TIBA), p-chlorophenoxyisobutyric acid (PCIB), p-chlorophenylalanine (p-CPA), d-amphetamine, fluoxetine (Prozac) and methylphenidate (Ritalin). ' In vitro' morphogenesis was found to be significantly affected by relative ratio of serotonin to melatonin thereby poviding the first indication of a role for indoleamine hormones in the regulation of plant morphogenesis.
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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 | 0.000 | 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 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".