RESUMO
The tendency of using herbs extracts or natural compounds extracted from herbs for preventing or treating different illnesses, including cancer, continues to be an alternative to drug use. Many studies of plant compounds aimed at finding substances with selective cytotoxicity on abnormal cells. Phenolic compounds, as important secondary metabolites from plants, are one of them. In this review, the recent literature data from the past five years about anticancer/antitumor effect of flavonoids and tannins extracted from medicinal plants are surveyed. The cytostatic/antitumor effects of the individual compounds extracted from plants and/or of the plants' polyphenolic extracts are considered, in order to point out the most significant constituents or plants with anticancer potential. The most important results concerning these compounds and their derivatives in cancer prevention and treatment, the importance of their chemical structure, their mechanism of action in vitro and in vivo, and some bioavailability aspects are discussed.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Flavonoides/farmacologia , Neoplasias/tratamento farmacológico , Extratos Vegetais/farmacologia , Plantas Medicinais/química , Taninos/farmacologia , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/isolamento & purificação , Proliferação de Células/efeitos dos fármacos , Ensaios de Seleção de Medicamentos Antitumorais , Flavonoides/química , Flavonoides/isolamento & purificação , Humanos , Estrutura Molecular , Neoplasias/patologia , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Taninos/química , Taninos/isolamento & purificaçãoRESUMO
We report the experimental results that refer to a Fourier transform Raman (FT-Raman) survey of thermally altered Baltic and Romanian amber and the related statistical interpretation of data using principal component analysis (PCA). Although FT-Raman spectra show several small changes in the characteristic features of the investigated amber samples which may be used for discrimination, their visual recognition is relatively difficult, especially when interpreting data from archeological samples, and thus multivariate data analysis may be the solution to more accurately assign the geological origin based on overall characteristic spectral features. The two categories of amber have different behavior in terms of degradation during the experimental alteration, and Romanian amber is more susceptible to physico-chemical transformations by the aggressive environment when compared with Baltic amber. The obtained data were in accordance with the Fourier transform infrared (FT-IR) remarks published previously in a dedicated journal. The Raman technique is an alternative method that requires little to no sample preparation, water does not cause interference, and the spectra can be collected from a small volume (1-50 µm in diameter).