Abiesanol A, a novel biflavanol with unique six connective hexacyclic rings isolated from Abies georgei. - Yang,X.W.; Li,S.M.; Feng,L.; Shen,Y.H.; Tian,J.M.; Zeng,H.W.; Liu,X.H.; Shan,L.; Su,J.; Zhang,C.; Zhang,W.D. (Tetrahedron Lett, 2008)