Chan Agnes L-F, Huang Hui-Lin, Chien Hui-Chi, Chen Chi-Ming, Lin Chun-Nan, Ko Wun-Chang
Pharmacy Department, Chi Mei Medical Center, 901 Chung-Hwa Road, Tainan, 710, Taiwan.
Invest New Drugs. 2008 Oct;26(5):417-24. doi: 10.1007/s10637-008-9114-7. Epub 2008 Feb 9.
Rolipram has high (PDE4(H)) and low (PDE4(L)) affinities for phosphodiesterase (PDE)-4, respectively. In general, it is believed that inhibitions by PDE4(H) and PDE4(L) are respectively associated with an adverse response and with anti-inflammatory and bronchodilating effects. This has provided a rational basis for designing new compounds with high PDE4(H)/PDE4(L) ratios. In the present study, we attempted to determine the PDE4(H)/PDE4(L) ratios of quercetin (1), qercetin-3-O-methylether (3-MQ, 2), quercetin-3,7,4'-O-trimethylether (ayanin, 3), quercetin-3,7,3',4'-O- tetramethylether (QTME, 4), quercetin-3,5,7,3',4'-O-petamethylether (QPME, 5), quercetin-3,5,7,3',4'-O-pentaacetate (QPA, 6), and quercetin-3-O-methyl-5,7,3',4'-O-tetraacetate (QMTA, 7). The activities of PDE1 approximately 5, which were partially separated from homogenates of guinea pig lungs and hearts, were measured by a two-step procedure using adenosine 3',5'-cyclic monophosphate (cAMP) with [(3) H]-cAMP or guanosine 3',5'-cyclic monophosphate (cGMP) with [(3) H]-cGMP as substrates. The IC(50) values of all of these compounds except quercetin (1), 3-MQ (2), and QMTA (7) on PDE1 approximately 5 inhibition were determined. The anti-inflammatory effects of PDE4 inhibitors were reported to be associated with inhibition of PDE4 catalytic activity. Therefore, these IC(50) values for PDE4 inhibition were taken as the PDE4(L) values. The effective concentration (EC(50)), at which one half of the [(3) H]-rolipram bound to high-affinity rolipram binding sites (HARBSs) of brain cell membranes was replaced, was defined as the PDE4(H) value. In the present results, the PDE4(H)/PDE4(L) ratios of quercetin (1), ayanin (3), and QPME (5) were >30, >19, and 11, respectively (Table 1), which are higher than or equal to that of AWD12-281, the selective PDE4 inhibitor with the greatest potential currently undergoing clinical trials for treating asthma and chronic obstructive pulmonary disease.
咯利普兰对磷酸二酯酶（PDE）-4分别具有高亲和力（PDE4(H)）和低亲和力（PDE4(L)）。一般认为，PDE4(H)和PDE4(L)的抑制作用分别与不良反应以及抗炎和支气管扩张作用相关。这为设计具有高PDE4(H)/PDE4(L)比值的新化合物提供了合理依据。在本研究中，我们试图测定槲皮素（1）、槲皮素-3-O-甲基醚（3-MQ，2）、槲皮素-3,7,4'-O-三甲醚（白杨素，3）、槲皮素-3,7,3',4'-O-四甲醚（QTME，4）、槲皮素-3,5,7,3',4'-O-五甲醚（QPME，5）、槲皮素-3,5,7,3',4'-O-五乙酸酯（QPA，6）和槲皮素-3-O-甲基-5,7,3',4'-O-四乙酸酯（QMTA，7）的PDE4(H)/PDE4(L)比值。通过两步法，以腺苷3',5'-环磷酸（cAMP）与[³H]-cAMP或鸟苷3',5'-环磷酸（cGMP）与[³H]-cGMP为底物，测定从豚鼠肺和心脏匀浆中部分分离出的PDE1至5的活性。测定了除槲皮素（1）、3-MQ（2）和QMTA（7）之外的所有这些化合物对PDE1至5抑制作用的半数抑制浓度（IC₅₀）值。据报道，PDE4抑制剂的抗炎作用与抑制PDE4催化活性有关。因此，这些PDE4抑制的IC₅₀值被视为PDE4(L)值。将使与脑细胞膜高亲和力咯利普兰结合位点（HARBSs）结合的[³H]-咯利普兰半数被取代时的有效浓度（EC₅₀）定义为PDE4(H)值。在本研究结果中，槲皮素（1）、白杨素（3）和QPME（5）的PDE4(H)/PDE4(L)比值分别>30、>19和11（表1），高于或等于目前正在进行治疗哮喘和慢性阻塞性肺疾病临床试验的最具潜力的选择性PDE4抑制剂AWD12 - 281的该比值。
