A phytochemical investigation to search for new nitric oxide (NO) inhibitors resulted in the isolation of seven previously undescribed daphnane diterpenoids, thyrsoidpenes A-G, from the leaves of Trigonostemon thyrsoideus. Their structures including absolute configurations were elucidated on the basis of extensive NMR spectroscopic data analysis and the time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. Thyrsoidpenes B-G feature rare polycyclic caged structures of daphnane diterpenoid orthoester. The NO inhibitory effects were examined and all of the compounds showed inhibitory activities toward LPS-induced NO production in murine microglial BV-2 cells. The possible mechanism of NO inhibition of some bioactive compounds was also investigated using molecular docking, which revealed the interactions of bioactive compounds with the iNOS protein.

中文翻译：

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具有一氧化氮抑制活性和与来自 Trigonostemon thyrsoideus 叶子的 iNOS 相互作用的达芬烷二萜

一项寻找新的一氧化氮 (NO) 抑制剂的植物化学研究导致从 Trigonostemon thyrsoideus 的叶子中分离出七种以前未描述的达芬烷二萜类化合物 thyrsoidpenes AG。基于广泛的 NMR 光谱数据分析和瞬态密度泛函理论 (TDDFT) 电子圆二色性 (ECD) 计算，阐明了它们的结构，包括绝对构型。Thyrsoidpenes BG 具有罕见的达芬烷二萜原酸酯多环笼状结构。检查了 NO 抑制作用，所有化合物都显示出对 LPS 诱导的小鼠小胶质细胞 BV-2 细胞中 NO 产生的抑制活性。还使用分子对接研究了 NO 抑制某些生物活性化合物的可能机制，