Drug and Herbal Research Centre, Faculty of Pharmacy, Universiti Kebangsaan Malaysia, Jalan Raja Muda Abdul Aziz, 50300 Kuala Lumpur, Malaysia.
Molecules. 2012 Apr 26;17(5):4824-35. doi: 10.3390/molecules17054824.
Acetylmelodorinol, chrysin and polycarpol, together with benzoic acid, benzoquinone and stigmasterol were isolated from the leaves of Mitrella kentii (Bl.) Miq. The compounds were evaluated for their ability to inhibit prostaglandin E₂ (PGE₂) and thromboxane B₂ (TXB₂) production in human whole blood using a radioimmunoassay technique. Their inhibitory effect on platelet activating factor (PAF) receptor binding to rabbit platelet was determined using ³H-PAF as a ligand. Among the compounds tested, chrysin showed a strong dose-dependent inhibitory activity on PGE(2) production (IC₅₀ value of 25.5 µM), which might be due to direct inhibition of cyclooxygenase-2 (COX-2) enzymatic activity. Polycarpol, acetylmelodorinol and stigmasterol exhibited significant and concentration-dependent inhibitory effects on TXB₂ production with IC₅₀ values of 15.6, 19.1 and 19.4 µM, respectively, suggesting that they strongly inhibited COX-1 activity. Polycarpol and acetylmelodorinol showed strong dose-dependent inhibitory effects on PAF receptor binding with IC₅₀ values of 24.3 and 24.5 µM, respectively.
从米仔兰（Mitrella kentii）（Bl.）Miq 的叶子中分离得到了乙酰基麦角醇、白杨素和多卡醇，以及苯甲酸、苯醌和豆甾醇。采用放射免疫测定技术，评估这些化合物抑制人全血中前列腺素 E₂（PGE₂）和血栓素 B₂（TXB₂）生成的能力。使用 ³H-PAF 作为配体，测定它们对血小板激活因子（PAF）受体与兔血小板结合的抑制作用。在所测试的化合物中，白杨素对 PGE（2）的产生具有很强的剂量依赖性抑制活性（IC₅₀ 值为 25.5 µM），这可能是由于直接抑制环加氧酶-2（COX-2）的酶活性。多卡醇、乙酰基麦角醇和豆甾醇对 TXB₂的产生具有显著的浓度依赖性抑制作用，IC₅₀ 值分别为 15.6、19.1 和 19.4 µM，表明它们强烈抑制 COX-1 活性。多卡醇和乙酰基麦角醇对 PAF 受体结合具有很强的剂量依赖性抑制作用，IC₅₀ 值分别为 24.3 和 24.5 µM。
