Administration of an aqueous extract of the calcinogenic plant Solanum malacoxylon (S.m.) to vitamin D-deficient or strontium fed chicks produces significant plasma 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) activity within 6 hr. (via radioreceptor assay) and subsequently elicits the appearance of immunoreactive intestinal calcium binding protein. Studies of a purified aqueous extract of S.m. show that it does not compete effectively with radioactive 1,25-(OH)2D3 for binding to the sterol's intestinal receptor. However, treatment of the extract with β-glucosidase releases a biologically active substance which is soluble in organic solvents and efficiently competes with labeled sterol for the receptor. This factor migrates exactly with tritiated 1,25-(OH)2D3 on high resolution Celite liquid-liquid partition columns. Thus, S.m. contains a molecule very similar or identical to 1,25-(OH)2D3 which is combined with one or more carbohydrate moieties in the native plant. This glycoside is probably cleaved in vivo before biological activity is attained.
|Original language||English (US)|
|Number of pages||8|
|Journal||Biochemical and Biophysical Research Communications|
|State||Published - Jun 7 1976|
ASJC Scopus subject areas
- Molecular Biology
- Cell Biology