HPLC-based activity profiling of Salvia miltiorrhiza for MAO A and iNOS inhibitory activities.

In the course of a screening of plant extracts for potential CNS and anti-inflammatory activities, a dichloromethane extract of Salvia miltiorrhiza showed a pronounced inhibitory effect on recombinant monoamine oxidase A (MAO A) and on inducible NO synthase (iNOS) induction in Raw 267.4 cells. With the aid of HPLC-based profiling techniques, activities could be linked, to a significant extent, to peaks of tanshinone-type diterpenoids, four of which were subsequently isolated. The IC50 of the most active compound, 15,16-dihydrotanshinone I, on human recombinant MAO A was at 23 microM, and 2.4 microM on lipopolysaccharide-mediated iNOS induction in Raw 267.4 cells.