Three New Polyprenylated Benzophenone Derivatives Isolated from Clusia burle-marxii.

Three new polyprenylated benzophenone derivatives named burlemarxione G-I (1-3) were isolated from C. burle-marxii trunks (compound 1) and leaves (compounds 2 and 3), along with the known compound burlemarxione F. Burlemarxione G (1) was isolated after methylation with diazomethane and it is the keto-enol tautomeric pair of burlemarxione F. Burlemarxione H (2) derives from burlemarxiones F and G, but it has additional rings due to cyclization of the prenyl group attached to C-5 that establishes new single bonds between C-1 and C-23, as well as, between C-24 and C-29. Burlemarxione I (3) has two additional cyclizations: the first encompasses the cyclization of the former isopentenyl group into an 11,11-dimethyl-six-membered ring, whereas the second produces additional rings due to the cyclization of the prenyl group attached to C-5 that establishes new single bonds between C-1 and C-23, as well as, between C-24 and C-29. All three compounds showed moderate anti-glioma activity. These results show that C. burle-marxii is an important source of sophisticated polyprenylated benzophenone derivatives.

2,4-Thiazolidinedione as Precursor to the Synthesis of Compounds with Anti-glioma Activities in C6 and GL261 Cells.

BACKGROUND: Thiazolidinediones (TZDs) represent an important class of heterocyclic compounds that have versatile biological activities, including anticancer activity. Glioma is one of the most common primary brain tumors, and it is responsible for most of the deaths caused by primary brain tumors. In the present work, 2,4-thiazolidinediones were synthesized via a multicomponent microwave one-pot procedure. The cytotoxicity of compounds was analyzed in vitro using rat (C6) and mouse (GL261) glioblastoma cell lines and primary cultures of astrocytes. OBJECTIVE: This study aims to synthesize and characterize 2,4-thiazolidinediones and evaluate their antitumor activity. METHODS: TZDs were synthesized from three components: 2,4-thiazolidinedione, arene-aldehydes, and aryl chlorides. The reactions were carried out inside a microwave and monitored using thinlayer chromatography (TLC). Compounds were identified and characterized using gas chromatography coupled to mass spectrometry (CG-MS) and hydrogen (1H-NMR) and carbon nuclear magnetic resonance spectroscopy (13C-NMR). The antitumor activity was analyzed using the 3-(4,5- dimethyl)-2,5-diphenyltetrazolium bromide (MTT) reduction test, in which cell viability was verified in the primary cultures of astrocytes and in rat and mouse glioblastoma cells exposed to the synthesized compounds. The cytotoxicity of all derivatives was analyzed at the 100 µM concentration, both in astrocytes and in the mouse and rat glioblastoma cell lines. The compounds that showed the best results, 4CI and 4DI, were also tested at concentrations 25, 50, 100, 175, and 250 µM to obtain the IC50. RESULTS: Seventeen TZD derivatives were easily obtained through one-pot reactions in 40 minutes with yields ranging from 12% to 49%. All compounds were cytotoxic to both glioblastoma cell lines without being toxic to the astrocyte primary cell line at 100 µM, thus demonstrating a selective activity. Compounds 4CI and 4DI showed the best results in the C6 cells: IC50 of 28.51 µM and 54.26 µM, respectively. CONCLUSION: The compounds were not cytotoxic in astrocyte culture, demonstrating selectivity for malignant cells. Changes in both rings are important for anti-glioma activity in the cell lines tested. TZD 4CI had the best anti-glioma activity.

Reverted effect of mesenchymal stem cells in glioblastoma treated with agathisflavone and its selective antitumoral effect on cell viability, migration, and differentiation via STAT3.

Glioblastoma is the most lethal tumor of the central nervous system, presenting a very poor prognostic, with a survival around 16 months. The interaction of mesenchymal stem cells and tumor cells has been studied, showing a bias in their role favoring or going against aggressiveness. Natural products such as flavonoids have showed their anticancer properties and the synergic potential with the activation of microenvironment cells to inhibit tumor progression. Agathisflavone is a flavonoid studied in neurodegenerative diseases and cancer. The present study investigated the effect of flavonoid in the viability of heterogeneous glioblastoma (GBM) cells considering a coculture or conditioned medium of mesenchymal stem cells (MSCs) effect, as well as the dose-dependent effect of this flavonoid in tumor migration and differentiation via STAT3. Agathisflavone (3-10 µM) induced dose-dependent toxicity to GL-15 and U373 human GBM cells, since 24 h after treatments. It was not toxic to human MSC but modified the pattern of interaction with GBM cells. Agathisflavone also inhibited migration and increased differentiation of human GBM cells, associated with the reduction on the expression of STAT3. These results demonstrate that the flavonoid agathisflavone had a direct anti-glioma effect. However, could be observed its effect in MSCs response that may have an impact in controlling GBM growth and aggressiveness, an important factor to consider for new therapies.