Determination of Сatharanthus flower anthocyanins [Определение видового состава антоцианов цветков Сatharanthus]

Using the reversed phase high performance liquid chromatography with diode-array and mass-spectrometric (in ESI mode) detection, a composition of Catharanthus roseum petals was established. After the acid hydrolysis, all five anthocyanidins were found to be different comparing to the ordinary anthocyanidins from Vitis vinifera fruits. The anthocyanins were elucidated to be 7-O-methyl derivatives of delphinidin, cyanidin, petunidin, peonidin and malvidin by the analysis of retention in RP HPLC, mass- and UV-visible spectra. The anthocyanins were characterized with UV-visible spectra, having the same fixtures as the set of non-methylated (in position 7) anthocyanin with hypsochromic (4 nm) of spectral maxima. The absorption bands for 7-methylcyanidin and 7-methylpeonidin aglycons and derivatives were indistinguishable while for the set of 7-methydelphinidin, 7-methypetunidin and 7-methylmalvidine (hirsutidin) a consecutive shift of absorption maxima by approximately 1 - 1.5 nm was found. The same was true for non-methylates at position 7 derivatives. The analysis of retention of anthocyanins of the flowers including the comparison with the retention of Mangifera indica skin anthocyanins, mass- and UV-visible spectra indicated that a minor set of anthocyanins included two sets of derivatives. The minor compounds were found to be 3-galactosides for samples under investigation, while the set of the major anthocyanins was represented by 3-rhamnosylgalactosides. Indeed, though through mass-spectra it was not possible to differentiate 3-rhamnosylgalatosides and 3-(p-coumaroylgalactosides) because of m/z coincidence, the retention difference between the two found anthocyanins sets as well as UV-visible spectra excluded the latter type of derivatives. © 2019 Ural Federal University. All rights reserved.