Cytotoxic vobasine, tacaman, and corynanthe-tryptamine bisindole alkaloids from Tabernaemontana and structure revision of tronoharine

  • J Nat Prod. 2014 Nov 26;77(11):2504-12. doi: 10.1021/np500589u.
Dawn Su-Yin Sim  1 ,  Kam-Weng Chong ,  Choy-Eng Nge ,  Yun-Yee Low ,  Kae-Shin Sim ,  Toh-Seok Kam
Affiliations
  • 1. Department of Chemistry and ‡Institute of Biological Sciences, University of Malaya , 50603 Kuala Lumpur, Malaysia.
PMID: 25333996 DOI: 10.1021/np500589u
Abstract

Seven new Indole Alkaloids (1-7) comprising four vobasine, two tacaman, and one corynanthe-tryptamine bisindole alkaloid were isolated from the stem-bark extract of a Malayan Tabernaemontana. Two of the new vobasine Alkaloids (1, 3), as well as 16-epivobasine (15) and 16-epivobasenal (17), showed appreciable cytotoxicity toward KB cells (IC50 CA. 5 μg/mL). The structure of the known Tabernaemontana alkaloid tronoharine (8) was revised based on newly acquired NMR data, as well as X-ray diffraction analysis.