AUTHOR=Fei Dong-Qing , Li Hui-Hong , Chen Xiao-Han , Cui Wen-Bo , Zhang Zong-Ping , Zhan Xiao-Qing , Wang Mei-Jie , Qi Feng-Ming , Zhang Zhan-Xin , Li Er-Wei 

TITLE=Caesalpinbondin A, a Novel Diterpenoid Lactone With an Unprecedented Carbon Skeleton from the Seeds of Caesalpinia bonduc

JOURNAL=Frontiers in Chemistry

VOLUME=Volume 10 - 2022

YEAR=2022

URL=https://www.frontiersin.org/journals/chemistry/articles/10.3389/fchem.2022.911543

DOI=10.3389/fchem.2022.911543

ISSN=2296-2646

ABSTRACT=One novel diterpenoid lactone named caesalpinbondin A (1) that possesses an unprecedented tetracyclic ring system in which a 6/6/5-fused tricyclic ring and a 4,5-dimethyldihydrofuran-2(3H)-one was connected by a C-C single bond comprising a 5-(naphtho[2,3-b]furan-7-yl)dihydrofuran-2(3H)-one moiety was isolated from the seeds of Caesalpinia bonduc. Its chemical structure was established by extensive spectroscopic methods, and its absolute configuration was further determined by single-crystal X-ray diffraction analysis and electronic circular dichroism (ECD) calculation. Biological evaluation suggested that compound 1 demonstrated potent anti-Alzheimer’s disease (AD) bioactivity, which could delay paralysis of transgenic AD Caenorhabditis elegans. A possible biogenetic pathway of 1 was also proposed.