A. F. Hess (New York) and A. Windaus (Gottingen, Germany) tested 30 different steroids with more than 1 double bond from various plant sources for antirachitic activity. Upon irradiation they found that ergosterol , a fungal steroid from ergot which when irradiated , was highly active in curing rats suffering from rickets14. In consultation with Rosenheim and Webster they also determined the ergosterol was the provitamin D which was convertible to vitamin D by UV irradiation15.
In 1931 Reerink et al. and Windaus and his co-workers purified and crystallized the irradiation product of ergosterol. It was then named D-2 or calciferol and when given (0.01 g/d) to rachitic rats for 2 months effected a complete cure16-18. After structurally identified and chemically synthesized from yeast, vitamin D was directly added to milk at a standard of 400 IU (1 IU= 25 ng) per …show more content…
The exact sequence of steps leading to the photoproduction of cholecalciferol in the skin was reported by Holick et al. in 1980.
Vitamin D exists in several forms like D1, D2 D3 D4, and D5. The two major forms are vitamin D2 or ergocalciferol and vitamin D3 cholecalciferol. Chemically, the various forms of vitamin D are secosteroids i.e. steroids in which one of the bonds in the steroid rings is broken. The structural difference between vitamin D2 and vitamin D3 is in their side chains25. The side chain of D2 contains a double bond between carbon 22 and 23, and a methyl group on carbon 24.
Vitamin D3 is produced by ultraviolet irradiation (UV) of its precursor 7-dehydocholesterol. This molecule occurs naturally in the skin of animal and milk. Vitamin D2 is a derivative of ergosterol, which is produced by some organisms of phytoplankton, invertebrates, yeast and higher fungi such as mushrooms. Vitamin D2 is not produced by land plants or vertebrate, since they lack the precursor
In 1931 Reerink et al. and Windaus and his co-workers purified and crystallized the irradiation product of ergosterol. It was then named D-2 or calciferol and when given (0.01 g/d) to rachitic rats for 2 months effected a complete cure16-18. After structurally identified and chemically synthesized from yeast, vitamin D was directly added to milk at a standard of 400 IU (1 IU= 25 ng) per …show more content…
The exact sequence of steps leading to the photoproduction of cholecalciferol in the skin was reported by Holick et al. in 1980.
Vitamin D exists in several forms like D1, D2 D3 D4, and D5. The two major forms are vitamin D2 or ergocalciferol and vitamin D3 cholecalciferol. Chemically, the various forms of vitamin D are secosteroids i.e. steroids in which one of the bonds in the steroid rings is broken. The structural difference between vitamin D2 and vitamin D3 is in their side chains25. The side chain of D2 contains a double bond between carbon 22 and 23, and a methyl group on carbon 24.
Vitamin D3 is produced by ultraviolet irradiation (UV) of its precursor 7-dehydocholesterol. This molecule occurs naturally in the skin of animal and milk. Vitamin D2 is a derivative of ergosterol, which is produced by some organisms of phytoplankton, invertebrates, yeast and higher fungi such as mushrooms. Vitamin D2 is not produced by land plants or vertebrate, since they lack the precursor