Two new coumarins (1 and 2), together with six known compounds (3–8), were isolated from the stem bark of Fraxinus rhynchophylla. The structures of these compounds were established by extensive spectroscopic studies and chemical evidence. The inhibitory activities of the isolated compounds (1–8) against human neutrophil elastase (HNE) were evaluated in vitro; all compounds tested exhibited inhibitory effects against HNE activity, with IC₅₀ values ranging from 3.6–74.3 μM. Among the compounds tested, compounds 2 and 8 exhibited considerable HNE inhibitory activity, with IC₅₀ values of 3.6 and 9.6 μM, respectively. The mechanism by which the two active compounds (2 and 8) inhibited HNE was noncompetitive inhibition, with inhibition constant (K_i) values of 2.2 and 6.8 μM, respectively. Furthermore, compounds 2 and 8 dose-dependently inhibited LPS-induced NO production in RAW 264.7 cells. Consistent with these findings, they also suppressed LPS-induced expression of iNOS and COX-2 at the protein level in RAW 264.7 cells.

两个新的香豆素（1和2），加上6种已知化合物（3 - 8），从茎树皮中分离大叶白蜡。这些化合物的结构是通过广泛的光谱研究和化学证据确定的。在分离的化合物（的抑制活性1 - 8）对人嗜中性粒细胞弹性蛋白酶（HNE）体外进行评价; 所有测试的化合物均显示出对HNE活性的抑制作用，IC ₅₀值为3.6–74.3μM。在测试的化合物中，化合物2和8表现出可观的HNE抑制活性，具有IC_50个值分别为3.6和9.6μM。两种活性化合物（2和8）抑制HNE的机制是非竞争性抑制，抑制常数（K _i）值分别为2.2和6.8μM。此外，化合物2和8剂量依赖性地抑制了LPS诱导的RAW 264.7细胞中NO的产生。与这些发现一致的是，他们还抑制了RAW 264.7细胞中LPS诱导的iNOS和COX-2蛋白的表达。