Structural characterization of polymeric polyphenols from different parts of Diospyros kaki L. cv. Mopan persimmons

Polymeric polyphenols in different parts (fruits, leaves and calyces) of persimmon ( Diospyros kaki L. cv. Mopan) were characterized via four different degradation methods, followed by HPLC/UPLC-UV/vis, HPLC/UPLC-Q-Exactive-Orbitrap/MS and UPLC-QqQ/MS to obtain comprehensive structural constituent unit information of polymeric polyphenols. The results indicated that persimmon polymeric polyphenols not only consisted of proanthocyanidins as terminal and extension units, but also contained anthocyanidins, flavonols and phenolic acids as terminal units. Among these different fragments detected, (−)-gallocatechin, (−)-gallocatechin-3- O -gallate, (+)-catechin and (+)-catechin-3 -O- gallate as extension units and (−)-epicatechin, (−)-gallocatechin, (−)-epigallocatechin, eight phenolic acids and four flavonols as terminal units were found for the first time in persimmon polymeric polyphenols. The molar percentages of constitutive units of persimmon polymeric polyphenols varied considerably. Compared to polymeric polyphenols in persimmon fruits and calyces, anthocyanidins, flavonols and phenolic acid units with the highest molar percentages were found in polymeric polyphenols in persimmon leaves. In contrast, the mean polymerization degrees of polymeric polyphenols in persimmon fruits, leaves and calyces were 26.45 ± 0.43, 6.23 ± 0.08 and 11.60 ± 0.07, respectively. These findings provide, for the first time, comprehensive structural information on persimmon polymeric polyphenols, and offer valuable insights into their composition and characteristics.