Two novel dimeric indole alkaloids from the leaves and twigs of Psychotria henryi.

Two novel dimeric indole alkaloids were isolated from the leaves and twigs of Psychotria henryi. Their structures were established by chemical and spectroscopic methods. Compound 1 was a novel dimeric tryptamine-related alkaloid that contained an unprecedented decacyclic ring system, and compound 2 featured a pyrido[3,4-b]indole moiety adjacent to a pyrrolidinoindole skeleton. The absolute configurations of compounds 1 and 2 were determined by calculation of electronic circular dichroism (ECD) using density functional theory (DFT).