Perfil de separação de antocianinas em capim-elefante (Cenchrus purpureus Schum.)

Abstract

Pennisetum purpureum Schumach, (purple elephant grass, syn (Cenchrus purpureus (Schumach.) Morrone) has the characteristic color displayed by plants that have anthocyanins, a natural dye that has an effect against cardiovascular and neurodegenerative diseases, benefits the intestinal microbiota and can prevent cancer. This study aimed to obtain the profile of anthocyanin separation in elephant grass by chromatographic and spectroscopic techniques in order to optimize the extraction process and identify different anthocyanins in purple elephant grass focusing on the needs of industrial routines. The samples composed of purple-colored elephant grass leaves were analysed. The mixture design methodology tested different proportions of water, ethanol and methanol for anthocyanin extraction. The special cubic model determined solvent effects wiyh statistical significance by analysis of variance. Then, analysis was performed in Liquid Chromatography coupled to the Mass Analyzer (HPLC-MS) to identify the anthocyanins found. With the results of total anthocyanin content in each extract, it was possible to verify that, in relation to pure reagents, ethanol extracts anthocyanins more efficiently. Using two reagents, the high anthocyanin content was obtained by mixing water and ethanol (3:7), which is similar to the mixtures most used for other types of materials. The mixtures of three components are better for the extraction of anthocyanins in elephant grass, since the highest value found by the model was in the mixture of water:ethanol:methanol 4:4:2. It can be seen from the analysis in HPLC-MS that the binary mixtures and the ternary mixture are the most promising in terms of quantity of different anthocyanins in the same extract and the pure solvents demonstrate to have less power to extract different substances. From the identification of the separate substances, it can be inferred that pelargonidin 3-robinobioside and malvidin are more common in purple elephant grass extracts.