Effect of Constituent Units, Type of Interflavan Bond, and Conformation on the Antioxidant Properties of Procyanidin Dimers: A Computational Outlook

Table 4

Fukui indices of the procyanidin dimers calculated by the M05-2X/6- DFT method using the Hirshfeld charge population analysis in an aqueous medium (SMD model).

Procyanidin dimer	Atom/unit	Nucleophilic attack	Atom/unit	Electrophilic attack
PB3 Com	C4′ EU	0.095	O5 TU	0.085
PB3 Ext	C4′ TU	0.097	O4′ EU	0.104
PB4 Com	C4′ EU	0.095	O5 TU	0.088
PB4 Ext	C4′ TU	0.098	O5 TU	0.083
PB5	C4′ EU	0.105	O3′ EU	0.116
PB6	C4′ EU	0.096	O7 TU	0.056
PB7	C4′ EU	0.095	O7 TU	0.099
PB8	C4′ EU	0.097	O4′ EU	0.049

PB3 (C4α–C8, catechin); PB4 (C4α–C8, catechin-epicatechin); PB5 (C4β–C6, epicatechin); PB6 (C4α–C6, catechin); PB7 (C4β–C6, epicatechin-catechin); PB8 (C4α–C6, catechin-epicatechin).
EU: extension unit; TU: terminal unit.