Betulin (Bet), the main component of birch tree bark, has been recently reported to exert anticancer activity in several cell lines; however the underlying mechanisms are only partially elucidated. The aims of the present work were to assess the in vivo effects of betulin administered as nanoemulsion (NE) in two experimental models: (i) the chicken embryo chorioallantoic membrane (CAM) assay for the study of anti-angiogenic effects and (ii) the two-stage model of skin carcinoma induced in mice for the study of anti-tumor and anti-inflammatory effects, respectively. On the CAM of the chicken betulin in nanoemulsion (BetNE) shows a good penetrability at extra-embryonic tissue level, affecting both the chorioallantoic membrane as well as the yolk sac by reducing the capillary density. In the animal model, the potential impact of local application of betulin on the respiratory function of isolated liver mitochondria was further assessed. Topical application of betulin nanoemulsion for 12 weeks together with DMBA (7,12-dimethylbenz[a]anthracene) and TPA (12-O-tetradecanoylphorbol 13-acetate), as tumor initiator and promoter, enhanced the active respiration of isolated liver mitochondria. Betulin also inhibit skin tumor apparition and promotion, proved by histological results and VEGF (vascular endothelial growth factor) expression correlated to non-invasive measurements. Betulin is active in nanoemulsion formulation as a potential inhibitory on the angiogenic process in CAM assay. BetNE can develop a potent anti-inflammatory and anti-carcinogenic activity with a low toxicity at skin level. It can also influence the penetration of carcinogens and reduce damage in main organs (e.g., liver).
Betulin, an important compound found in birch tree bark, can be converted to betulinic acid, an important pharmacological substance. Betulin has recently been reported as a cytotoxic agent for several tumor cell lines and as an apoptotic inductor. Angiogenesis is a key process involved in tumor metastasis and in developing tumor resistance to cytotoxic therapy. There are little data on betulin as an anti angiogenic agent. This preliminary study aimed to evaluate the cytotoxic effect of betulin on three cancer cell lines: HeLa (cervix adenocarcinoma), MCF7 (breast adenocarcinoma) and A431 (skin epidermoid carcinoma), and the apoptotic mechanism, as well as the implication in the capillary formation of the chicken embryo chorioallantoic membrane. The analysis consisted in the interpretation of the MTT assay and fluorescence double staining with Hoechst dye 33258 and propidium iodide, while the angiogenic effect was evaluated using morphological and immunohistochemical techniques. The antitumor activity is revealed by the double fluorescence staining, indicating that at higher concentrations, the cell membrane permeability is enhanced, while at lower concentrations there is evidence for nuclear fragmentation. In what concerns its effect on the process of blood vessel formation, betulin induced the reduction of newly formed capillaries, especially in the mesenchyme, possible through targeting the normal function of endothelial cells. In vitro results proved the superior specificity of betulin on cervical cancer cells, followed by skin cancer cells.
BackgroundThe isoflavonoid genistein represents the major active compound from soybean, the vegetal product from Glycine max (Fabaceae). The aim of this study is to prove that genistein was incorporated in two semisynthetic cyclodextrins, beta-cyclodextrin derivatives: hydroxypropyl-beta-cyclodextrin and randomly-methylated-beta-cyclodextrin as well as to compare the anti-inflammatory activity of genistein with that of genistein incorporated in these two types of semisynthetic cyclodextrins.ResultsThe animal studies were conducted on 8-week old C57BL/6 J female mice. Inflammation was induced in both ears of each mouse by topical application of 10 micrograms 12-O-tetradecanoylphorbol-3-acetate dissolved in 0.1 ml solvent (acetone : dimethylsulfoxide in a molar ratio 9:1). Thirty minutes later treatment was applied. The inflammatory reaction was correlated with increased values in ear thickness. Treatment with genistein and genistein incorporated in the two cyclodextrins led to decreased values for ear thickness. Better anti-inflammatory action was found for the complexes of genistein. Both haematoxylin-eosin analysis and CD45 marker expression are in agreement with these findings.ConclusionsResults allow concluding that genistein is an active anti-inflammatory phytocompound and its complexation with hydrophilic beta-cyclodextrin derivatives leads to a stronger anti-inflammatory activity.
Vascular endothelial growth factor-A (VEGF-A) and hepatocyte growth factor (HGF) are well known angiogenesis inductors and promoters in normal and pathologic conditions. Recent data showed that VEGF-A and HGF could also influence lymphangiogenesis but this matter has not been completely elucidated. Administration of VEGF-A and HGF in combination has been used to improve the angiogenic response in different experimental models, but their effects on lymphangiogenesis have not been investigated. The aim of this study was to characterize blood and lymphatic vascular response to VEGF-A/HGF administration. To this purpose, we built a pBlast VEGF-A/HGF combination suitable for in vivo research. By using as an experimental in vivo model the chick embryo chorioallantoic membrane (CAM) assay, we applied pBlast VEGF-A/HGF combination for 7 days. Results showed that VEGF-A/HGF combination was able to induce a strong angiogenic response and the expression of Prox-1 in the lymphatic endothelial cells of the CAM. The possible mechanisms involved have been speculated.
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