Three new seco-polycyclic polyprenylated acylphloroglucinols (PPAPs), ascyronones A-C (1-3), and a new biosynthetic precursor, ascyronone D (4), were isolated from Hypericum ascyron together with three known analogues (5-7). Compounds 1 and 2, sharing an unusual seven-membered carbon core fused with a gamma-lactone ring, could be derived from 1,9-seco-PPAPs via further rearrangement. A biomimetic transformation from 5 to 1 was performed by using base-driven retro-Claisen and rearrangement cascade reaction, which further confirmed the structure of 1 and shed light to its possible biosynthetic pathway. Interestingly, all these compounds are decorated with a methyl group at C-5 instead of a prenyl or geranyl group in many other PPAPs. The isolates were evaluated for their inhibitory activities against five human tumor cell lines. (C) 2017 Elsevier Ltd. All rights reserved.
1.Chinese Acad Sci, Kunming Inst Bot, State Key Lab Phytochem & Plant Resources West Ch, Kunming 650201, Peoples R China 2.Yunnan Key Lab Nat Med Chem, Kunming 650201, Peoples R China 3.Univ Chinese Acad Sci, Beijing 100049, Peoples R China 4.Kunming Med Univ, Sch Pharmaceut Sci, Kunming 650500, Peoples R China 5.Kunming Med Univ, Yunnan Key Lab Pharmacol Nat Prod, Kunming 650500, Peoples R China 6.COMSATS Inst Informat Technol, Dept Chem, Abbottabad 22060, Pakistan
Recommended Citation:
Kong, Ling-Mei,Long, Xian-Wen,Yang, Xing-Wei,et al. seco-Polycyclic polyprenylated acylphloroglucinols with unusual carbon skeletons from Hypericum ascyron[J]. TETRAHEDRON LETTERS,2017,58(22):2113-2117.
