The water soluble calcinogenic factor present in the plant Solanum malacoxylon is partially purified by selective extraction and chromatography on silicic acid and then hydrolyzed with a mixed preparation of glycosidases from the sea worm, Charonia lampus. Hydrolysis produces a chloroform soluble factor with biologic characteristics of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3), the hormonal form of vitamin D. Purification of this factor is accomplished by chromatography on Sephadex LH-20, silicic acid, and Celite columns, yielding 3 μg of active material. During the isolation, bioactivity (as assessed by the ability of fractions to compete with labeled 1,25-(OH)2D3 for binding to a specific intestinal receptor protein) migrates exactly with authentic tritiated 1,25-(OH)2D3. The purified factor has an ultraviolet absorption spectrum identical to that of 1,25-(OH)2D3 and analysis via direct probe mass spectrometry yields a parent molecular ion of m/e 416 and a fragmentation pattern indistinguishable from synthetic 1,25-(OH)2D3 hormone. We therefore conclude that the vitamin D-like principle in Solanum malacoxylon is a sterol-glycoside which contains the 1,25-(OH)2D3 molecule as its active sterol component.
ASJC Scopus subject areas
- Biochemistry, Genetics and Molecular Biology(all)
- Pharmacology, Toxicology and Pharmaceutics(all)