Tropane alkaloids from Erythroxylum caatingae Plowman.

Three tropane alkaloids, 1-3, were isolated from Erythroxylum caatingae, i.e., 6ß-benzoyloxy-3α-[(4-hydroxy-3,5-dimethoxybenzoyl)oxy]tropane (1), a new tropane alkaloid, along with the known alkaloids 3α,6ß-dibenzoyloxytropane (2) and 6ß-benzoyloxy-3α-[(3,4,5-trimethoxybenzoyl)oxy]tropane (catuabine B; 3). Their structures were determined by 2D- ((1) H and (13) C) NMR. By LC/ESI-MS/MS analysis of the fractions of alkaloids 1-3, it was possible to detect five more alkaloids, 4-8, two of these, 4 and 8, possibly being new natural products. X-Ray crystallography of the chloride derivate of 1, i.e., 6ß-benzoyloxy-3α-(4-hydroxy-3,5-dimethoxybenzoyloxy)tropane hydrochloride (1a) confirmed the structure of 1. Cytotoxicity was tested against the cell lines HEp-2, NCI-H292, and KB for the MeOH extract and alkaloid 3, and antitumor activity was tested against Sarcoma 180 only for the MeOH extract.

Selective cytotoxic and genotoxic activities of 5-(2-bromo-5-methoxybenzylidene)-thiazolidine-2,4-dione against NCI-H292 human lung carcinoma cells.

BACKGROUND: Thiazolidine-2,4-dione ring system is used as a pharmacophore to build various heterocyclic compounds aimed to interact with biological targets. In the present study, benzylidene-2,4-thiazolidinedione derivatives (compounds 2-5) were synthesized and screened against cancer cell lines and the genotoxicity and cytotoxicity of the most active compound (5) was investigated on normal and lung cancer cell line. METHODS: For in vitro cytotoxic screening, the MTT assay was used for HL60 and K562 (leukemia), MCF-7 (breast adenocarcinoma), HT29 (colon adenocarcinoma), HEp-2 (cervix carcinoma) and NCI-H292 (lung carcinoma) tumor cell lines and Alamar-blue assay was used for non-tumor cells (PBMC, human peripheral blood mononuclear cells) were used. Cell morphology was visualized after Giemsa-May-Grunwald staining. DNA content, phosphatidylserine externalization and mitochondrial depolarization were measured by flow cytometry. Genotoxicity was assessed by Comet assay. RESULTS: 5-(2-Bromo-5-methoxybenzylidene)-thiazolidine-2,4-dione (5) presented the most potent cytotoxicity, especially against NCI-H292 lung cancer cell line, with IC50 value of 1.26µg/mL after 72h incubation. None of the compounds were cytotoxic to PBMC. After 48h incubation, externalization of phosphatidylserine, mitochondrial depolarization, internucleosomal DNA fragmentation and morphological alterations consistent with apoptosis were observed in NCI-H292 cells treated with compound (5). In addition, compound (5) also induced genotoxicity in NCI-H292 cells (2.8-fold increase in damage index compared to the negative control), but not in PBMC. CONCLUSION: Compound 5 presented selective cytotoxic and genotoxic activity against pulmonary carcinoma (NCI-H292 cells).

Synthesis and cytotoxic profile of glycosyl-triazole linked to 1,2,4-oxadiazole moiety at C-5 through a straight-chain carbon and oxygen atoms.

The convergent synthesis of an unusual (but simple) class of compounds 5a-g has been achieved by the copper-catalyzed [3+2] cycloaddition reaction of 2,3,4,6-tetra-O-acetyl-beta-D-glucopyranosyl azide 4 with propynyl 3-[3-(aryl)-1,2,4-oxadiazol-5-yl] propionates 3a-g. The formerly known azide 4 has been prepared according to the literature procedure; however, the synthesis of esters 3a-g is being reported for the first time. The infrared as well as (1)H NMR spectra of all new products are in agreement with their proposed structures. By carrying out the nOe experiment of one of the final compounds 5a, we have been able to establish that only the 1,4-regioisomers have been formed in the cycloaddition reaction. All final products presented weak cytotoxic activity, but 5e and 5g had somewhat better behaviour showing 22-25% cell growth inhibition against two cell strains: NCI-H(292) (lung carcinoma) and HEp-2 (larynx carcinoma).

Synthesis, antimicrobial and cytotoxic activities of some 5-arylidene-4-thioxo-thiazolidine-2-ones.

Several 5-arylidene-4-thioxo-thiazolidine-2-ones (3a-n) were synthesized and evaluated as antimicrobial agents against representative strains, including multidrug-resistant strains of clinical isolates. Also, the antiproliferative activity was evaluated against two human carcinoma cell lines (NCI-H292 and HEp-2). The compounds containing the 5-arylidene subunit presented greater antimicrobial activities against Gram positive bacteria, including the multidrug-resistant clinical isolates, than the 4-thioxo-thiazolidine-2-one. Important SAR information was also gathered, such as the contribution of thiocarbonyl attached at 4-position on the thiazolidine heterocyclic for antimicrobial properties. None of the derivatives exhibited significant antiproliferative activity against the human carcinoma cell lines.