No abstract

Several resveratrol analogues have been designed to improve bioactivity: among these polymethoxystilbenes appear to be particularly promising. The present study was set up to investigate the biological functions of polymethoxystilbenes 2 and 3, recently found in our lab as antiangiogenic agents, on a well-defined swine granulosa cell model. Proliferative activity and effects on steroidogenesis were evaluated, as well as the effect on granulosa cell vascular endothelial growth factor (VEGF) production, since these cells in basic conditions synthesize the main proangiogenic peptide. Moreover, we considered the effect of these two resveratrol analogues on granulosa cell redox status. Analogue 3 inhibited granulosa cell growth, while it stimulated steroidogenesis. A similar effect was displayed by 2 on estradiol 17beta production and cell proliferation at the highest concentration tested. On the other hand, at the same dosage 2 decreased progesterone levels. Both analogues inhibited VEGF output. Granulosa cell redox status was unaffected by resveratrol analogue 2 while the highest concentration of 3 stimulated free radicals generation and scavenging enzyme activities. The overall results indicate that analogue 3 is the more powerful compound, thus suggesting that a slight modification in the structure markedly increases effectiveness. These data could be useful to develop more active resveratrol analogues for therapeutic use.

No abstract

Angiogenesis is normally a highly regulated process that occurs during development, reproduction, and wound repair. However, angiogenesis can also become a fundamental pathogenic process in cancer and several other diseases. To date, the synthesis of angiogenesis inhibitors has been researched in several ways also starting from bioactive plant compounds. In the present study, we tested both in an angiogenesis bioassay and in ovarian cell culture, the potential antiangiogenic effect of a natural-derived benzo[k,l]xanthene lignan (5). This unusual compound was synthesized through the biomimetic dimerization of CAPE (caffeic acid phenethyl ester), a bioactive component of honeybee propolis. The lignan showed a significant, dose-related inhibitory effect on new vessel growth in the angiogenesis bioassay and it inhibited Vascular Endothelial Growth Factor secretion in ovarian cell culture. Therefore, we indicate the natural-derived benzo[k,l]xanthene lignan 5 as a potential new angiogenesis inhibitor.

A mild treatment of the resveratrol analogue 3,5,4'-trimethoxystilbene 2 with m-CPBA afforded two hydroxylated methoxystilbenes 5 and 6 by direct aromatic hydroxylation. A similar protocol was applied to other stilbenes bearing a 3,5-dimethoxy moiety, namely tetramethoxystilbenes 7 and 10 to obtain respectively the hydroxylated analogues 8, 9 and 11, 12. The substrate 2 and the new compounds 5, 8 and 11 were evaluated as anti-angiogenic agents and proved significantly active in the range 1-100 μM.