title: Anticancer effects of brominated indole alkaloid Eudistomin H from marine ascidian Eudistoma viride against cervical cancer cells (HeLa).
abstract: Marine invertebrates called ascidians are prolific producers of bioactive substances. The ascidian Eudistoma viride, distributed along the Southeast coast of India, was investigated for its in vitro cytotoxic activity against human cervical carcinoma (HeLa) cells by the MTT assay. The crude methanolic extract of E. viride, with an IC50 of 53 μg/ml, was dose-dependently cytotoxic. It was more potent at 100 μg/ml than cyclohexamide (1 μg/ml), reducing cell viability to 9.2%. Among nine fractions separated by chromatography, ECF-8 exhibited prominent cytoxic activity at 10 μg/ml. The HPLC fraction EHF-21 of ECF-8 was remarkably dose- and time-dependently cytotoxic, with 39.8% viable cells at 1 μg/ml compared to 51% in cyclohexamide-treated cells at the same concentration; the IC50 was 0.49 μg/ml. Hoechst staining of HeLa cells treated with EHF-21 at 0.5 μg/ml revealed apoptotic events such an cell shrinkage, membrane blebbing, chromatin condensation and formation of apoptotic bodies. Cell size and granularity study showed changes in light scatter, indicating the characteristic feature of cells dying by apoptosis. The cell-cycle analysis of HeLa cells treated with fraction EHF-21 at 1 μg/ml showed the marked arrest of cells in G0/G1, S and G2/M phases and an increase in the sub G0/G1 population indicated an increase in the apoptotic cell population. The statistical analysis of the sub-G1 region showed a dose-dependent induction of apoptosis. DNA fragmentation was also observed in HeLa cells treated with EHF-21. The active EHF-21 fraction, a brominated indole alkaloid Eudistomin H, led to apoptotic death of HeLa cells.
authors.affiliation: Molecular Biophysics Unit, Indian Institute of Science, Bangalore, India jeshran@gmail.com.
authors.forename: Rajaian Pushpabai
authors.initials: RP
authors.lastname: Rajesh
authors.affiliation: Marine Ecology and Conservation Lab, P.G. & Research Dept. of Zoology, V.O. Chidambaram College, Tuticorin, India.
authors.forename: Murugan
authors.initials: M
authors.lastname: Annappan
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000302:isolation & purification / Q000494:pharmacology*; D017209:Apoptosis; D002243:Carbolines / Q000302:isolation & purification / Q000494:pharmacology; D059447:Cell Cycle Checkpoints; D002470:Cell Survival / Q000187:drug effects; D003513:Cycloheximide / Q000494:pharmacology; D004249:DNA Damage; D004260:DNA Repair; D004354:Drug Screening Assays, Antitumor; D006367:HeLa Cells; D006801:Humans; D020128:Inhibitory Concentration 50; D014561:Urochordata / Q000737:chemistry
chemical_list: D000970:Antineoplastic Agents; D002243:Carbolines; C056221:eudistomin H; D003513:Cycloheximide
keywords: Ascidian; DNA fragmentation; Eudistoma viride; HeLa; apoptosis; cytotoxicity; flow cytometry