Fig. 2

a DAD spectrum of the chromatographic peak assigned to murexide in sample P.24 (“Murexide Cristallisée 1890”); b HPLC-DAD chromatogram of the DMSO extract acquired at 480 nm; c tandem mass spectrum (30 V) of the parent ion at m/z = 265.0, assigned to murexide in the HPLC-ESI-Q-ToF chromatogram showing the characteristic mass fragments of murexide. The structure of the crystallized murexide is provided in the inset