Related Experiment Video
Updated: Jul 7, 2026

System for Efficacy and Cytotoxicity Screening of Inhibitors Targeting Intracellular Mycobacterium tuberculosis
Published on: April 5, 2017
Spin-labeled rifamycin: biological activity
Z Z Raykov1, K Vassilev, G Grigorova
1German Cancer Research Center, Heidelberg, Germany.
Abstract:
3-[(2,2,6,6-Tetramethylpiperidine-4-ylimino)methyl]rifamycin (4) and spin-labeled rifamycin-3-[(2,2,6,6- tetramethyl-1-oxyl-piperidine-4-ylimino)methyl]rifamycin (1) were prepared. The structures of these compounds were determined by IR, UV, MS and 1H NMR of 4. The ESR-spectrum of 1 is a symmetric triplet signal, characteristic of nitroxyl radicals, g = 2.0025. An in vitro comparative study of the cytotoxicity and antitumor activity of 1, 4 and the initial 3-formyl-rifamycin was carried out in concentrations from 0.1 to 0.001 mM on cells before and after oxidative stress (preliminary irradiation 7Gy) on MH3924A-hepatoma rat cells, 293 transformed human fibroblasts, NBK transformed human fibroblasts and HT 1080 human fibrosarcoma. The compounds showed a cytostatic effect to 85%, with 1 being less toxic in the hepatoma cell line. In human melanoma cell lines 1 showed a higher toxicity than 4. All the derivatives (1 and 4) have in vitro antibacterial activity comparable with that of rifampicin.
Insights
New spin-labeled rifamycin derivatives (1 and 4) exhibit significant antitumor and antibacterial activity. Compound 1 showed differential toxicity in cancer cell lines, with potential applications in cancer therapy and infectious diseases.
Area of Science:
- Medicinal Chemistry
- Pharmacology
- Biochemistry
Background:
- Rifamycin derivatives are explored for their therapeutic potential.
- Spin-labeling and structural modification can alter drug properties.
- Understanding cytotoxicity and antitumor activity is crucial for drug development.
Purpose of the Study:
- To synthesize and characterize novel spin-labeled rifamycin derivatives.
- To evaluate the in vitro cytotoxicity and antitumor activity of these derivatives.
- To compare their efficacy against initial rifamycin and against each other in various cell lines.
Main Methods:
- Synthesis of 3-[(2,2,6,6-Tetramethylpiperidine-4-ylimino)methyl]rifamycin (4) and spin-labeled rifamycin-3-[(2,2,6,6-tetramethyl-1-oxyl-piperidine-4-ylimino)methyl]rifamycin (1).
- Structural elucidation using IR, UV, MS, and 1H NMR.
- Electron spin resonance (ESR) spectroscopy for spin-labeled compound.
- In vitro cytotoxicity and antitumor assays on rat hepatoma and human fibroblast/fibrosarcoma cell lines, with and without oxidative stress.
Main Results:
- Compounds 1 and 4 demonstrated a cytostatic effect of up to 85%.
- Compound 1 exhibited lower toxicity in the hepatoma cell line compared to compound 4.
- In human melanoma cell lines, compound 1 showed higher toxicity than compound 4.
- Both derivatives displayed in vitro antibacterial activity comparable to rifampicin.
Conclusions:
- The novel spin-labeled rifamycin derivatives possess significant in vitro antitumor and antibacterial properties.
- Compound 1 demonstrates potential for targeted cancer therapy due to differential toxicity.
- These findings support further investigation of these rifamycin derivatives as therapeutic agents.
Related Concept Videos
Inhibitors of Bacterial Protein Synthesis
Inhibitors of Viral Protein Synthesis
