Combined effect of flavonoids-pectin ternary complexes on in vitro pancreatic lipase activity

Nowadays, natural options to inhibit pancreatic lipase (PL) as part of obesity treatments have been studied, where vegetables’ bioactive compounds, such as flavonoids, represent an option. However, other compounds like pectin (PEC) can also be found in these products. Due to the scarce studies that analyze the effect of combined inhibitory effect of flavonoids (Catechin, CAT; Epicatechin, EPI; and Naringenin, NAR) both in presence and absence of PEC, this work was carried out. Combination index (CI) values and isobolograms on PL activity were determined. The enzymatic activity was measured using UV-Vis spectroscopy. Six different flavonoids’ combinations, alone and in conjunction with PEC were evaluated. Without PEC, IC50 values for individual flavonoids were similar, and they exhibited an uncompetitive inhibition mode. According to the CI values and the isobolograms, synergistic effects (CI < 0.90) were predominantly observed for flavonoids combinations, regardless of the presence of PEC. It appeared to enhance the inhibitory capacity of the flavonoid-flavonoid combinations, contributing to a stronger synergistic effect on PL activity. Notably, the EPI-NAR combination in both the presence and absence of PEC demonstrated the most significant synergistic inhibitory effect, with CI values of 0.58 ± 0.02 and 0.68 ± 0.00, respectively.