Mycalosides B−I, Eight New Spermostatic Steroid Oligoglycosides from the Sponge Mycale laxissima

• Published in: Journal of natural products (Washington, D.C.) Vol. 66; no. 8; pp. 1082 - 1088
• Main Authors: Antonov, Alexandr S, Afiyatullov, Shamil Sh, Kalinovsky, Anatoly I, Ponomarenko, Ludmila P, Dmitrenok, Pavel S, Aminin, Dmitry L, Agafonova, Irina G, Stonik, Valentin A
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01-08-2003
• Subjects: animal products; Animals; arabinose; carbon; chemical structure; Cuba; Fertilization - drug effects; galactose; glucose; glycosides; Glycosides - chemistry; Glycosides - isolation & purification; Glycosides - pharmacology; glycosidic linkages; Male; Molecular Structure; Mycale laxissima; mycalosides; Nuclear Magnetic Resonance, Biomolecular; Porifera; Porifera - chemistry; protons; Sea Urchins - drug effects; spectral analysis; Spermatozoa - drug effects; stereochemistry; Stereoisomerism; steroids; Steroids - chemistry; Steroids - isolation & purification; Steroids - pharmacology; Strongylocentrotus nudus; tetraosides; Cuba
• ISSN: 0163-3864; 1520-6025
• DOI: 10.1021/np0300030

New steroidal oligoglycosides mycalosides B−I (2−9) have been isolated from the polar extract of the Carribean sponge Mycale laxissima, and their structures have been elucidated by 1D and 2D NMR (1H, 13C, DEPT, COSY-45, COSY-RCT, HSQC, HMBC, and NOESY spectra) and MALDI-TOF mass spectrometry. Mycalosides B (2) and C (3) were shown to be 27- and 28-nor derivatives of the previously known tetraoside mycaloside A (1). Mycaloside D (4) differs from 1 only in the presence of an additional acetyl group in the carbohydrate moiety. Mycaloside E (5) was structurally identified as a 28-nor-4-dehydroxy derivative of 1. Mycalosides F−H (6−8), differing from each other by the structures of their side chains and nonacetylated (7, 8) or acetylated (6) tetrasaccharide carbohydrate moieties, have new 5(6)-unsaturated 3β,4β,21-trihydroxy-15-keto-steroidal aglycons. Mycaloside I (9) is a tetraoside of a new 7,24(28)-diunsaturated 3β,15β,29-trihydroxystigmastane aglycon. It was established that the total fraction of the mycalosides as well as mycalosides A (1) and G (7) inhibit the fertilization of eggs by sperm of the sea urchin Strongylocentrotus nudus preincubated with these compounds.