Catechol-O-Methyltransferase Inhibitors Isolated From Thai Propolis

Abstract

Propolis is an aggregate of functional components found in plant resins and has been reported to exhibit a variety of valuable biological activities. This study investigated the inhibitory properties of propolis from Thailand toward human catechol-O-methyltransferase (COMT), a key neurotransmitter involved in Parkinson's disease and depression. Samples collected from Chanthaburi and Chiang Mai exhibited relatively high inhibitory activity against COMT. γ-Mangostin (1) and 6-prenyleriodictyol (3) were identified as COMT inhibitors with IC50 values of 62 and 75 μM, respectively. In an enzyme inhibition assay, 1 exhibited mixed inhibition toward COMT. The results suggest that both 1 and propolis have potential applications in the prevention and treatment of psychological illness.