Abstract
Analysis of the Philippine marine sponge Xestospongia ashmorica afforded four new manzamine congeners 1-4 and four known compounds 5 and 7-9. Compound 1 is the 6-deoxy derivative of manzamine X, while 2-4 are the N-oxides of manzamine J (5), 3,4-dihydromanzamine A (6), and manzamine A (7), respectively. The structures of the new compounds were unambiguously established on the basis of NMR spectroscopic (1H, 13C, COSY, 1H-detected direct, and long-range 13C-1H correlations) and mass spectrometric (EI, FAB-MS, and electrospray ionization) data. Alkaloid N-oxide structures were confirmed by conversion to the corresponding tertiary bases by reduction with Zn/HCl. This is the first report of the occurrence of bioactive manzamine N-oxides in marine sponges. Compound 7 exhibited insecticidal activity toward neonate larvae of the polyphagous pest insect Spodoptera littoralis (with an ED50 of 35 ppm) when incorporated in artificial diet and offered to larvae in a chronic feeding bioassay. Compound 7 was also active against the Gram-positive bacteria Bacillus subtilis and Staphylococcus aureus. Cytotoxicity was studied in vitro using L1578y mouse lymphoma cells. From the alkaloids studied, the N-oxides 3 and 4 were the most active (ED50 = 1.6 micrograms/mL) followed by compound 7 (ED50 = 1.8 micrograms/mL).
Original language | English |
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Pages (from-to) | 1056-1060 |
Number of pages | 5 |
Journal | Journal of Natural Products |
Volume | 59 |
Issue number | 11 |
Early online date | 22 Nov 1996 |
DOIs | |
Publication status | Published - Nov 1996 |
Keywords
- alkaloids
- animals
- anti-bacterial agents
- antineoplastic agents
- drug screening assays, antitumor
- insecticides
- magnetic resonance spectroscopy
- mice
- microbial sensitivity tests
- philippines
- porifera
- spectrometry, mass, fast atom bombardment
- spectrophotometry, infrared
- tumor cells, cultured