However, the calculated dipole moments in the gas phase and in water (μV and μW, respectively) indicate that Bn is slightly more polar than iBn, a fact that would explain the higher retention times under reversed-phase conditions of the latter. The deconvolution of absorption spectra using a mixed-function approach results in good fitting of experimental spectra for samples containing betanin and different amounts of other substances. Determination of the concentration of the mixture of betanin/isobetanin by corrected spectrophotometry is in agreement with quantitative chromatographic data when the amount of impurities
absorbing at 400–480 nm and at around ISRIB purchase 530 nm is small. Processed samples containing betanin have higher amounts of its epimer isobetanin
than fresh extract. Comparison of methods for the purification of betanin indicates that ion-exchange chromatography is very efficient and is able to resolve the betanin/isobetanin mixture. However, this method is time-consuming and the amount of salt in the purified fractions results in high specific conductance. Consequently, both RP-HPLC and RP column chromatography methods provide the best balance between SCR7 order speed and efficiency. The longer retention time of isobetanin when compared to betanin, under reversed-phase conditions, results from higher interaction of the former with the non-polar stationary phase, as implied by the dipole moment calculated for these substances in the gas-phase and in water. We thank Prof. Dr. Antonio de Miranda (UNIFESP), Prof. Dr. Etelvino J.H. Bechara (IQ-USP/UNIFESP-Diadema)
and Prof. Dr. Nilson Antonio de Assunção (UNIFESP-Diadema) for their help in the early stages of this work, Prof. Ernani Pinto Junior (FCF-USP) and the Instituto Nacional de Ciência e Tecnologia de Análise Integrada do Risco Ambiental (INAIRA) for allowing us to use the HPLC-MS/MS equipment in his laboratory, and Prof. Frank H. Quina Selleckchem Ixazomib for a critical reading of the manuscript. Betanin in dextrin and lyophilised beetroot samples were kindly provided by Prof. Dr. Rainer Beckert and PD. Dr. Dieter Weiss (FSU-Jena, Germany). This work was partially supported by FAPESP (JP #07/00684-6, DD #07/59407-1), CAPES (PE/2007) and UFABC; ELB thanks the CNPq for a research productivity fellowship (#304887/2010-2). “
“The name of A. Heshmati was included in the authorship group of this article in error, and A. Heshmati was assigned as corresponding author by A. Yavari without notification. The correct author line appears above. “
“Paullinia cupana, which is known as guarana, is a climbing plant that is native to the central Amazon basin and cultivated exclusively in Brazil ( CEPLAC, 2011 and Kuri, 2008). The seeds contain 3.2–7.