Inhibition of catechol-O-methyltransferase (COMT) by some plant-derived alkaloids and phenolics
Articles > Article · 2010
Authors: Dilek Yalcin, Oğuz BAYRAKTAR
JOURNAL OF MOLECULAR CATALYSIS B-ENZYMATIC, Journal Indexed in SCI Expanded, International, WoS, 2010, vol 64, pp 162-166
DOI: 10.1016/j.molcatb.2009.04.014
Summary
In this study, as an alternative to the medicines, natural compounds extracted from plant species (Peganum harmala, Cistus parviflorus and Vitex agnus-cactus) were investigated in order to inhibit the catechol-O-metyhltranferase (COMT) activity. In fluorometric enzyme assay, S-adenosylmethionine (SAM) and aesculetin (ES) were used as methyl donor and acceptor substrates, respectively. Their K-m, values were determined as 3.5 +/- 0.3 mu M and 6.4 +/- 0.4 mu M in absence of inhibitor. Inhibition performances of the plant-derived polyphenolics and alkaloids were determined. Inhibitory effect of alkaloids extracted from P. harmala seeds was found the highest among the plant extracts; however, it was lower than that of 3,5-DNC. In case of inhibition mechanism, mixed type inhibition was observed for alkaloid extract whereas uncompetitive inhibition was observed for 3,5-DNC. In case of polyphenolic extracts obtained from C. parviflorus and V. agnus-cactus leaves, mechanism were also explained as mixed type inhibition and their alpha K-i values were calculated as 1.99 +/- 0.35 mu g/ml and 9.48 +/- 0.58 mu g/ml, respectively. (C) 2009 Elsevier B.V. All rights reserved.