8-Acetyl-9-hydroxy-3-methoxy-7-methyl-1-phenalenon

Anti-Complementary Components of Helicteres angustifolia.[Pubmed:27834928]

Molecules. 2016 Nov 10;21(11):1506.

A first phenalenon derivative with an acetyl side chain at C-8, 8-Acetyl-9-hydroxy-3-methoxy-7-methyl-1-phenalenon (compound 1), and a pair of new sesquilignan epimers at C-7'' of hedyotol C and hedyotol D analogs, hedyotol C 7''-O-beta-d-glucopyranoside (compound 2) and hedyotol D 7''-O-beta-d-glucopyranoside (compound 3) were isolated from the aerial parts of Helicteres angustifolia together with nine known compounds (4-12). Their structures were elucidated on the basis of spectroscopic methods, including mass spectroscopy, and 1D and 2D nuclear magnetic resonance. Eleven isolates exhibited anti-complementary activity. In particular, compounds 4 and 5 exhibited potent anti-complementary activities against the classical and alternative pathways with CH(50) values of 0.040 +/- 0.009 and 0.009 +/- 0.002 mM, and AP(50) values of 0.105 +/- 0.015 and 0.021 +/- 0.003 mM, respectively. The targets of compounds 4 and 5 in the complement activation cascade were also identified. In conclusion, the anti-complementary components of H. angustifolia possessed chemical diversity and consisted mostly of flavonoids and lignans in this study.