Inhibition of pancreatic lipase by black tea theaflavins: Comparative enzymology and in silico modeling studies

• Theaflavins inhibit pancreatic lipase (PL) at physiological concentrations.
• Theaflavin-3,3′-digallate (TFdiG) is the most potent inhibitor.
• TFdiG inhibits PL in a non-competitive manner with regard to substrate.
• An in silico model predicts that TFdiG binds adjacent to the PL active site.
• The model predicts that TFdiG perturbs His264, the key catalytic amino acid.

Few studies have examined the effect of black tea (Camellia sinensis) theaflavins on obesity-related targets. Pancreatic lipase (PL) plays a central role in fat metabolism and is a validated target for weight loss. We compared the inhibitory efficacy of individual theaflavins and explored the underlying mechanism. Theaflavin-3,3′-digallate (TFdiG), theaflavin-3′-gallate, theaflavin-3-gallate, and theaflavin inhibited PL with IC50 of 1.9, 4.2, 3.0, and >10 μmol/L. The presence and location of the galloyl ester moiety were essential for inhibitory potency. TFdiG exhibited mixed inhibition with respect to substrate concentration. In silico modeling showed that theaflavins bind to Asn263 and Asp206, which form a pocket adjacent to the active site, and galloyl-containing theaflavins are then predicted to perturb the protonation of His264. These data provide a putative mechanism to explain the anti-obesity effects of tea.