Bisbenzylisoquinoline (BBIQ) alkaloids occupy a special place among isoquinoline dimers with an ether bridge that have been isolated from plants.
BBIQ alkaloids have been observed in 27 species of plants from six genera of the families Berberidaceae, Magnoliaceae, Menispermaceae, and Ranunculaceae. The majority of 34 BBIQ found in the studied plants have been isolated from representatives of the genus Thalictrum. They all are dimers with two ether bridges. They include alkaloids with a fully aromatized isoquinoline moiety and partially hydrogenated ones. Quaternary BBIQ and N-oxides have also been observed.
Berbamunine, dauricine, magnoline, and magnolamine, being ditertiary bisbenzyltetrahydroisoquinolines with one ether bridge, have been observed in plants of the genera Berberis, Menispermum, and Magnolia, respectively.
Dimers with two ether bridges belong to the berbamine, thalicberine, hydroxyacanthine, thalmine, thalidasine, talphinine, or talphine types. The berbamine group...