Malvidin is a biologically active plant pigment, O-methylated anthocyanidin, that may be studied in cell signaling as an inhibitor of 3′,5′-cyclic adenosine monophosphate (cAMP) phosphodiesterases (PDE) and certain cGMP-specific phosphodiesterases. Malvidin may be used as a reference material in the analysis of anthocyanidin glycosides.