A New Cytotoxic Steroidal Glycoalkaloid from the Methanol Extract of Blumea lacera Leaves
Bibliographic record
Abstract
PURPOSE: Blumea lacera (B. lacera) (Asteraceae) is a well-known Bangladeshi medicinal plant. This study aimed to identify and characterize constituents associated with the significant cytotoxic activity of this plant that we reported previously. Here, we describe the isolation and characterization of a new steroidal glycoalkaloid (SGA) 1, the evaluation of its cytotoxic activity, apoptotic potential, and effect on cell cycle in comparison to analogous steroidal glycoalkaloids (SGAs). METHODS: SGA 1 was isolated using C18 SPE and HPLC, and subsequently structurally characterized using 1D and 2D NMR, MS and other spectroscopic methods, along with a comparative inspection of the literature. Cytotoxic activity of 1 and seven SGA analogues and steroidal alkaloids (SAs), (β-solamarine, α-solanine, β-solamargine, α-solasonine, khasianine, solasodine, tomatidine HCl) were evaluated for their cytotoxicity against two healthy (NIH3T3 and VERO) and four human cancer (AGS, HT-29, MCF-7 and MDA-MB-231) cell lines using the MTT assay. Cytotoxic SGAs were further evaluated for apoptosis-inducing potential and cell cycle arresting ability against breast cancer cells (MCF-7) using the FITC Annexin V and propidium iodide (PI) assay. RESULTS: Bioactivity guided fractionation of the methanol extract of B. lacera led to isolation of compound 1: (25R)-3β-{O-β-D-glucopyranosyl-(1 → 4)-O-α-L-rhamnopyranosyl-(1 → 4)-[O-α-L-rhamnopyranosyl-(1 → 2)]-α-L-rhamnopyranosyl}-22αN-spirosol-5-ene. SGA 1 was the most cytotoxic compound against a number of human cancer cell lines with an IC50 of 2.62 µM against MCF-7 cells. It displayed the highest apoptotic potential (32% AV+/PI-) on MCF-7 cells compared to other cytotoxic SGA analogues and a slight, but significant cell cycle arresting effect. CONCLUSIONS: A new SGA 1 was isolated from B. lacera and its cytotoxic activity, as well as that of other SAGs, was evaluated. SAR investigations on SGA 1, in relation to SGA analogues, show that the number and nature of sugar moieties along with the linkages of the sugar to the aglycone are crucial for cytotoxic and apoptotic activity. This article is open to POST-PUBLICATION REVIEW. Registered readers (see "For Readers") may comment by clicking on ABSTRACT on the issue's contents page.
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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".