A New Cytotoxic Carbazole Alkaloid Isolated from the Stem Bark of Malaysian Clausena excavata
Bibliographic record
Abstract
Abstract: Malaysia is one of the richest in its biodiversity in the world. There are not less than 12,000 plants species in its rain forest. The aim of this study is a continuous investigation for medicinal plants in Malaysia, especially the chemical constituents that are poses significant activities, i.e. anti-cancer. Clausena excavata (Rutaceae) has been known as a very rich in carbazole alkaloids, coumarins and limonoids species. In the present study, one new carbazole alkaloid, 1,8-dihydroxy-3-formyl-4-prenylcarbazole (Clausine–TH), and two other known compounds, Clausenarin (coumarin) and Clausine–K (carbazole alkaloid), were isolated from the methanol extract of the stem bark of Clausena excavata, collected from Kedah, Malaysia. Structures of these compounds were confirmed by various spectroscopic analyses including GC-MS, NMRs, and FTIR. All pure compounds isolated were tested for their cytotoxicity against CEM-SS cell lines, with the Clausine–TH and Clausine–K gave a very strong activity with an IC50 value of 2.1 µg/mL and 5.1 µg/mL, respectively.
Stored with the screening record, where it is evidence for the labels above.
How this classification was reachedexpand
The three-model screen
all 5,600 screened works →All three models called this out of scope.
Isolation of a cytotoxic alkaloid from a plant; natural-product chemistry.
The study isolates and tests plant compounds for cytotoxicity, not research itself.
Natural-product chemistry isolation of a cytotoxic alkaloid; domain biomedical chemistry.
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) | 0.002 | 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".