Strychnan and secoangustilobine A type alkaloids from Alstonia spatulata. Revision of the C-20 configuration of scholaricine

  • J Nat Prod. 2010 Nov 29;73(11):1891-7. doi: 10.1021/np100552b.
Shin-Jowl Tan  1 ,  Yun-Yee Low ,  Yeun-Mun Choo ,  Zanariah Abdullah ,  Tadahiro Etoh ,  Masahiko Hayashi ,  Kanki Komiyama ,  Toh-Seok Kam
Affiliations
  • 1. Department of Chemistry, University of Malaya, 50603 Kuala Lumpur, Malaysia.
PMID: 21043460 DOI: 10.1021/np100552b
Abstract

A total of 25 Alkaloids were isolated from the leaf and stem-bark extracts of Alstonia spatulata, of which five are new Alkaloids of the strychnan type (alstolucines A-E, 1-5) and the Other, a new alkaloid of the secoangustilobine A type (alstolobine A, 6). The structures of these Alkaloids were established using NMR and MS analysis and, in the case of alstolucine B (2), also confirmed by X-ray diffraction analysis. A reinvestigation of the stereochemical assignment of scholaricine (13) by NMR and X-ray analyses indicated that the configuration at C-20 required revision. Alkaloids 1, 2, 6, 7, 9, 10, and 13 reversed multidrug resistance in vincristine-resistant KB cells.

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