Monoamine Oxidase Inhibitory Coumarins from the Aerial Parts of Dictamnus albus

• Published in: Archives of pharmacal research 2006, Vol.29 (12), p.1119-1124
• Main Authors: Jeong, Seon-Hwa, Han, Xiang Hua, Hong, Seong-Su, Hwang, Ji-Sang, Hwang, Ji-Hye, Lee, Dong-Ho, Lee, Myung-Koo, Ro,, Jai-Seup, Hwang, Bang-Yeon
• Format: Article
• Language: Korean
• ISSN: 0253-6269; 1976-3786

The methanol extract from the aerial parts of Dictamnus albus was active in inhibiting monoamine oxidase (MAO) from the mouse brain. Activity-guided fractionation led to the isolation of four known coumarins, 7-(6'R-hydroxy-3', 7'-dimethyl-2'E, 7'-octadienyloxy) coumarin (1), auraptene (2), umbelliferone (3), and xanthotoxin (4), as active compounds along with an inactive alkaloid, skimmianine (5). Compounds 1 and 2 inhibited MAO activity in a concentration-dependent manner with $IC_{50}$ values of 0.7 and $1.7\;{\mu}M$, respectively. Compounds 1 and 2 showed a slight and potently selective inhibitory effect against MAO-B ($IC_{50}\;0.5\;and\;0.6\;{\mu}M,\;respectively$) compared to MAO-A ($IC_{50}\;1.3\;and\;34.6\;{\mu}M,\;respectively$). According to kinetic analyses derived by Lineweaver-Burk reciprocal plots, compounds 1 and 2 exhibited a competitive inhibition to MAO-B.