Disclosed is a sirtuin-modulating compound, or salt thereof, of formula III, wherein: R is -H or -CH3 R1 is a substituted or unsubstituted nitrogen-containing heterocyclylmethyl group R2 is -H or CH3 and R3 is an unsubstituted pyridyl group. Further disclosed is a pharmaceutical composition comprising a compound of formula III, and the use of a compound of formula III for use in the manufacture of a medicament for treating or preventing insulin resistance, a metabolic syndrome, diabetes, or complications thereof, or for increasing insulin sensitivity in a subject.