The oxidative depolymerization of proteracacinidins yields the anthocyanidin melacacinidin.
References
^L Bennie; E Malan; J Coetzee & D Ferreira (2000). "Structure and synthesis of ether-linked proteracacinidin and promelacacinidin proanthocyanidins from Acacia caffra". Phytochemistry. 53 (7): 785–793. doi:10.1016/S0031-9422(99)00618-4. PMID10783984.