22种拉布丹型二萜,包括十对15个差向异构体和一对13个15个差向异构体,是从著名的药用植物益母草Houtt的地上部分获得的。虽然这些差向异构体通过手性HPLC分离,它们的结构主要通过光谱方法,特别是核磁共振,X射线晶体学和ECD技术。其中,17种化合物,包括三对溶剂分解产物,可能是由于使用乙醇作为提取溶剂,在当前工作中首次被报道。我们的初步抗炎筛选表明,七种二萜对LPS诱导的RAW264.7细胞中NO的产生具有显著的抑制作用。此外,促炎因子TNF-α的释放,IL-1β和IL-6,以及iNOS和COX-2蛋白的表达,也被未报道的15,16-环氧-6β-羟基-15α-甲氧基-7,16-二氧杂环戊烯-8,13-二烯抑制。对该化合物的初步抗炎机制的进一步研究表明,它可以阻断NF-κB信号通路的激活。
Twenty-two labdane-type diterpenoids, including ten pairs of 15-epimers and a pair of 13,15-epimers, were obtained from the aerial parts of a well-known medicinal plant Leonurus japonicus Houtt. While these epimers were separated by chiral HPLC, their structures were established mainly via spectroscopic methods especially NMR, X-ray crystallography and ECD techniques. Among them, seventeen compounds, encompassing three pairs of solvolysis artefacts likely due to the use of ethanol as extracting solvent, were reported for the first time in the current work. Our preliminary anti-inflammatory screening demonstrated that seven diterpenoids displayed noteworthy inhibitory effect on the NO production in LPS-induced RAW264.7 cells. In addition, the release of pro-inflammatory factors TNF-α, IL-1β and IL-6, as well as the expression of iNOS and COX-2 proteins, was also suppressed by the unreported 15,16-epoxy-6β-hydroxy-15α-methoxy-7,16-dioxolabd-8,13-diene. Further investigation into the preliminary anti-inflammatory mechanism of this compound indicated that it could block the activation of NF-κB signaling pathway.