Determination of genotoxic, antigenotoxic and cytotoxic potential of the extract from lichen Cetraria aculeata (Schreb.) Fr. in vitro.

Naturally occurring compounds can have protective effects towards mutagens and carcinogens as shown by numerous studies. In the present study, the genotoxic/antigenotoxic activities of the extract from lichen Cetraria aculeata (Schreb.) Fr., which has been identified as an antibacterial agent in former studies, were investigated against known mutagens such as 4-nitro-o-phenylenediamine (4-NPD) and 2-aminofluorene (2-AF) in TA98 and TA100 strains of Salmonella typhimurium in the presence or absence of metabolic activity. Further genotoxicity/antigenotoxicity of the extract against mitomycin C for micronucleus formation was also evaluated in human lymphocytes. The cytotoxic effects of the extract on mammalian cells were investigated in three different cell line types by MTT assay. The results obtained show that the extract of C. aculeata has a significant antigenotoxic activity in bacterial systems, but not in mammalian cells and cytotoxic activity in some mammalian cancer cells. However, it was not mutagenic in all systems. The findings suggest that the lichen extract may have a possible therapeutic potential and therefore this must be further investigated by other multiple in vitro bioassays for the development of therapeutic agents.

The study on the synthesis and the effects on the intracellular calcium of some 9-substituted-phenanthrene derivatives.

Some 9-(substituted with heteroaryl)-phenanthrene compounds, polycyclic aromatic hydrocarbons (PAH), were obtained by two different methods. In the first method, 9-phenanthraldehyde was reacted with some dion compounds such as benzil, toluil, anisil, etc in the presence of ammonium acetate and glacial acetic acid. In the second method, 9-phenanthraldehyde was reacted with 5-substituted-1,2-phenylenediamine derivatives in the presence of NaHSO3 and ethanol. All of synthesized compounds by us were original and these compounds have not been studied in literature so far. The structures of compounds were confirmed by spectral data and elemental analyses results. The effects of compounds were studied on intracellular calcium level. All of the compounds were examined between the concentrations of 1 and 0.5 microg/mL.

Modification of intracellular free calcium in cultured F2408 embryo fibroblasts by 3-substituted-2-thiohydantoin derivatives.

3-substituted-2-thiohydantoin derivatives were synthesized and their structures elucidated by IR, 1H-NMR spectroscopy and elemental analysis. The cytotoxicity of the 2-thiohydantoin derivatives to rat embryo fibroblasts (F2408) in vitro was determined, and the effects of these compounds on intracellular free Ca2+, [Ca2+]i, were measured by spectrofluorophotometry. Cytotoxicity was determined by metabolic reduction of a tetrazolium salt to a formazan dye (MTT assay). Compounds 4 and 7 showed cytotoxic activity, with IC50 values in the range of 1-1.2 microM. Introduction of either chlorophenyl, metoxyphenyl, nitrophenyl or benzyl groups at C-3 resulted in concentration-dependent cytotoxic effects. Compounds 1-6 at 1 microM or more significantly increased [Ca2+]i in a dose-dependent manner in the cultured fibroblasts. This action may have been mediated through intracellular calcium stores.

Inhibition of DNA synthesis by carvacrol in mouse myoblast cells bearing a human N-RAS oncogene.

Monoterpenes are dietary components found in the essential oils of a wide variety of plants. A number of these monoterpenes have antitumor activity. We have investigated the effects of carvacrol obtained by fractional distillation of Origanum onites L. essential oil, on DNA synthesis of N-ras transformed myoblast cells, CO25. Incubation of the cells with different doses of carvacrol prevented DNA synthesis in the growth medium and ras-activating medium, which contains dexamethasone. This result demonstrates that carvacrol inhibits growth of myoblast cells even after activation of mutated N-ras oncogene, suggesting the possibility that carvacrol may find application in cancer therapy.