1,3,5-Trihydroxy-4-prenylxanthone

1,3,5-Trihydroxy-4-prenylxanthone is a relatively potent inhibitor of phosphodiesterase type 5 (PDE5) with an IC50 of 3.0 ?M; it exhibits in vitro inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) with IC50 values of 56.3plusmn;0.4 and 46.0plusmn;0.3 M, respectively. It also inhibits LPS-induced NF-?B and AP-1 activations by interfering with the posttranslational modification (phosphorylation and/or ubiquitinylation) of IRAK-1, disrupting TAK1-mediated activation of IKK and MAPKs signal transduction.