Abstract
Cell extracts from photoautrophic cultures of two cyanobacterial Calothrix isolates inhibited the growth in vitro of a chloroquine-resistant strain of the malaria parasite, Plasmodium falciparum, and of human HeLa cancer cells, in a dose-dependent manner. Bioassay-directed fractionation of the extracts led to the isolation and structural characterization of calothrixins A (1) and B (2), pentacyclic metabolites with an indolo[3,2- j]phenanthridine ring system unique amongst natural products, which exert their growth-inhibitory effects at nanomolar concentrations.
Original language | English |
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Pages (from-to) | 13513-13520 |
Number of pages | 8 |
Journal | Tetrahedron |
Volume | 55 |
Issue number | 47 |
DOIs | |
Publication status | Published - 19 Nov 1999 |