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Ten vobasinyl-ibogan type bisindole alkaloids, including three new ones, tabercorines A-C (1-3), and a new natural product, 17-acetyl-tabernaecorymbosine A (4), were isolated from the twigs and leaves of Tabernaemontana corymbosa. Their structures were elucidated on the basis of spectroscopic data, and the NMR data of 17-acetyl-tabernaecorymbosine A (4) was assigned and reported for the first time. The absolute configurations of 1-4 were determined by CD exciton chirality method. All new compounds were evaluated for in vitro cytotoxicity against various human cancer cell lines. Compounds 1 and 4 showed significant inhibitory effects with IC50 values comparable to those of cisplatin., (Copyright © 2014 Elsevier B.V. All rights reserved.)

The investigation of the seeds of Strychnos nux-vomica led to the isolation of two novel indole alkaloids, strynuxlines A (1) and B (2), with an unprecedented 6/5/9/6/7/6 hexacyclic ring system. Their structures and absolute configurations were elucidated on the basis of their MS, NMR, and ECD data. A plausible biosynthesis pathway of 1 and 2 is also proposed.

Ten new yuzurine-type Daphniphyllum alkaloids, daphmacromines A-J (1-10), along with seven known alkaloids were isolated from the leaves and stems of Daphniphyllum macropodum. Their structures were elucidated by extensive spectroscopic techniques, including 2D NMR spectroscopy and mass spectrometry, and the structure of 1 was confirmed by single-crystal X-ray diffraction. The pesticidal and cytotoxic activities of the isolated alkaloids were evaluated in vitro against brine shrimp (Artemia salina) and five human cancer cell lines (HL-60, SMMC-7721, A-549, MCF-7, and SW480), respectively. This study also suggested structural revisions of oxodaphnigracine, oxodaphnigraciline, and epioxodaphnigraciline.