Abstract 2888A: Prevention of MAPK pathway by Brazilian medicinal plant, Tabebuia avellanedae, on peroxynitrite induced carcinogenesis

Abstract

Abstract The present study was carried out to examine the chemopreventive activity of natural Brazilian medicinal plant, Tabebuia avellanedae ext. and its components on peroxynitrite(PN) induced carcinogenesis. Tabebuia avellanedae,(TA) which is a plant that has been used for herbal medicine in South America and from Brazil to northern Argentina, is well known in traditional folk medicne used for the treatment of various disease during five hundred years. The inner bark of this plant produced in Brazil is distributed in Asia as a herb tea and healthy purpose. On the fundamental findings, this substance was observed the inhibitory effects against chemical carcinogenesis induced tumor initiating and promoting activity using two-stage mouse skin model. In the course of these studies, female SENCAR mouse (6 weeks of age) were treated topically with single dose of PN solution, followed by TPA twice a weekly for 20 weeks. Tumor incidences were 100% with 6 to 7 paillomas per mouse at end of experiment as positive control group. TA powder were orally fed with drinking water for only 2 weeks, before and after initiation and following promoting treatment with drinking water only, as test compounds. In our observations, TA and its components treated group cause about 60-70 % reduction in the average number of tumors per mouse after 20 weeks of experiment, respectively. Topical administration of TA and its components had much influence against PN induced expression stage. We postulate that these data suggeste possible role of a regulatory mechanism of chemopreventive activity in PN induced carcinogenesis. Employing Western blot analysis studies, we found that H-Ras, MEK-2 and p38 levels observed the effects against PN induced activation, and more detail Western blot analysis indicated a active decrease in p38 expression in the skin after TA treatment. Summary of our findings, we suggest that one target of TA and its component effects in mouse skin is the modulation or regulation of the MAPK signaling. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 2888A.