Uncarialines A-E, new alkaloids from Uncaria rhynchophylla and their anticoagulant activity.

Uncarialines A-E (1-5), five undescribed monoterpene indole alkaloids, together with five known analogues were obtained from the stems of Uncaria rhynchophylla. Alkaloids 1-3 were unique 3,4-seco-tricyclic alkaloids with a 6/5/10 ring system, while 4 and 5 possessed a rare rearranged scaffold originated from corynantheine-type alkaloids with C-2/C-7 oxidation. Their structures were characterized by a comprehensive analysis of MS, NMR, and ECD.

New Monoterpenoid Indole Alkaloids from Inhibit -Amyloid42 Production and Phospho-Tau (Thr217).

Eleven monoterpenoid indole alkaloids, including three new ones, tabercrassines A-C (-), were isolated from the seeds of . Tabercrassine A () is an ibogan-ibogan-type bisindole alkaloid which is formed by the polymerization of two classic ibogan-type monomers through a C3 unit aliphatic chain. Their structures were established by extensive analysis of HRESIMS, NMR, and ECD spectra.