Biosynthetic relations between protoberberine-, benzo(C)phenanthridine- and B-secoprotoberberine type alkaloids in Corydalis incisa

The biosynthetic relations between protoberberine-, benzoC]phenanthridine- and B-secoprotoberberine type alkaloids were demonstrated by use of (±)-tetrahydrocoptisine-8,14-³H HCl, (±)-tetrahydrocorysamine-8,14-³H]HCl and corynoline-6-³H]HCl in Corydalis incisa, and the following results were presented. (±)-Tetrahydrocoptisine was converted to corynoline, corydalic acid methyl ester and corydamine hydrochloride. (±)-Tetrahydrocorysamine was converted to corynoline and corydalic acid methyl ester. Evidence that N-methyl-3-6′-(3′,4′-methylenedioxyphenethylalcohol)]-4-methyl-7,8-methylenedioxy-1,2,3,4-tetrahydroisoquinoline-α-³H] HCl was incorporated into corynoline-11-³H] indicates the occurrence of the ring fission at C₆-N followed by linking ofthe C₆ and C₁₃ positions in (±)-tetrahydrocoptisine and (±)-tetrahydrocorysamine, and suggests the participation of one of two possible intermediates in the biosynthesis of these alkaloids.