Abstract
The methanol-acetone (1:1) extract of the marine sponge Axinyssa ambrosia, collected along the Colombian Caribbean coast, yielded a mixture of 5α,8α-epidioxysterols, exhibiting cytotoxicity against cancer cells. The major compound identified was 5α,8α-epidioxi-(24R)-methylcholesta-6,22-dien-3β-ol 6, followed by 5α,8α-epidioxy[(24R)+(24S)]-ethylcholesta-6,22-dien-3β-ol 7, 5α,8α-epidioxy-(22E,24S)-methylcholesta-6,22,25(27)-trien-3β-ol 2, 5α,8α-epidioxycholesta-6,22-dien-3β-ol 3, 5α,8α-epidioxy-(22E,24R)-methylcholesta-6,9(11),22)-trien-3β-ol 4, and 5α,8α-epidioxy-(22E,24S)-ethylcholesta-6,22,25(27)-trien-3β-ol 5. The structures of compounds 1-7 were established using spectral methods (IR, MS, and NMR). The absolute stereochemistry at C-24 of compound 5, ambrosinosterol, was determined by comparing its spectral data with synthetic analogs. This is the first report of compound 5, ambrosinosterol, being isolated from nature. Additionally, previously unpublished spectral data for the synthetic compound (22E,24R)-ethylcholesta-5,22,25-trien-3β-ol 8 are also provided.
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References
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