Identification of glutathione S-transferase inhibiting natural products from Caesalpinia bonduc, Nauclea latifolia and Ambrosia psilostachya
Bibliographic record
Abstract
For this thesis, ph¡ochemical studies on three medicinally important plants, Caesalpinia bonduc, Nauclea latifulia and, Ambrosia psilostachya, werecarried out in a bid to isolate glutathione S-transferase inhibitors.A summary of this research work is described below.1. Phytochemical studies on the crude extract of Caesalpinia bonduc resulted in the isolation of neocaesalpin o (40), 17-hydroxy-campesta-4,6-dien-3-one (41), caesaldekarin J (42), apigenin (43), pipataline (44), betulinic acid (45), 73,74-seco- stigmasta-5,14-dien-3o-ol (46) and 13,14-seco-stigmasta-9(11),14-dien-3a-ol (47).These compounds showed weak to moderate or no inhibitory activities against GST, an enzyme that has been implicated in resistances of cancer cells and parasitic organisms towards chemotherapeutic agents.An attempt to study the structure- activity relationships of compounds 43, 44, 46 and 47 resulted in the synthesis of compounds 57-61.These compounds were also assayed, and some showed weak but enhanced GST inhibition.2. The chemical constituents of the crude ethanolic extract of Nauclea tatifuha were also investigated.This resulted in the isolation of strictosamide (70), quinovic acid-3-O-û,- quinovosylpyranoside (95), quinovic acid-3-O-B-rhamnosylpyranoside (96), quinovic acid-3-O-o-rhamnosylpyranoside (97) and quinovic acid-3-O-B-fucosylpyranoside (98).These compounds also showed varying extents of GST inhibitory activities with strictosamide (70) showing the best activity.Bioactivity data of the triterpenoidal glycosides (95-98) indicated that the nature of the sugar molecules attached to the quinovic acid aglycone may have an effect in their GsT-inhibiting potentials.J. V Similarly, ph¡ochemical studies on Ambrosía psilostachya have resulted in the isolation of coronopilin (100), a pseudoguaianolide sesquiterpene lactone.Coronopilin (100) showed a concentration-dependent weak inhibition of the activity of GST and no activity in an antifungal assay against two strains of Candida albicans.The structures of these compounds were deciphered by spectroscopic studies.The structure of compound 100 was also conf,rrmed by X-ray crystallographic studies.vl
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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".