Natural triterpenes exhibit a wide range of biological activities. Since this group of secondary metabolites is structurally diverse, effects may vary due to distinct biochemical interactions within biological systems. In this work, we investigated the anticancer-related activities of the quinone-methide triterpene maytenin and its derivative compound 22-β-hydroxymaytenin, obtained from Maytenus ilicifolia roots cultivated in vitro. Their antiproliferative and pro-apoptotic activities were evaluated in monolayer and three-dimensional cultures of immortalized cell lines. Additionally, we investigated the toxicity of maytenin in SCID mice harboring tumors derived from a squamous cell carcinoma cell line. Both isolated molecules presented pronounced pro-apoptotic activities in four cell lines derived from head and neck squamous cell carcinomas, including a metastasis-derived cell line. The molecules also induced reactive oxygen species (ROS) and down-regulated microRNA-27a and microRNA-20a/miR-17-5p, corroborating with the literature data for triterpenoids. Intraperitoneal administration of maytenin to tumor-bearing mice did not lead to pronounced histopathological changes in kidney tissue, suggesting low nephrotoxicity. The wide-ranging activity of maytenin and 22-β-hydroxymaytenin in head and neck cancer cells indicates that these molecules should be further explored in plant biochemistry and biotechnology for therapeutic applications.
SILVA, B. L. The effect of triterpenoids quinonamethide on the regulation of microRNAs associated with proliferation and apoptosis in head and neck cancer. 2016. 86 p. Dissertation (Master thesis in Biotechnology)-Instituto de Ciências Biomédicas,
The fragmentation of the Atlantic Forest is one of the main causes of habitat loss in this important global biodiversity hotspot. Amphibians are an integral part of this biodiversity and are the most threatened group of vertebrates on the planet, with some species declining mainly due to habitat loss; therefore, they are an important parameter to understand the effects of fragmentation. One of the least known aspects of this process is how the surrounding matrix fragments influence frog diversity and gene flow among these forest remnants. Moreover, few studies have analyzed genetic variability of
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