Baccinum undatum

The provitamins are more abundant in nature than the pure vitamins. Ergosterol is found in plants and yeast. 7-Dehydrocholesterol is the provitamin of man it is also found in animal skins. The most concentrated source, however, is in the snail Baccinum undatum, which contains about 27 percent 7-dehydrocholesterol in its dry weight. The D-vitamins themselves are not very widely distributed in nature. The richest sources are fish-liver oils, milk, and bird eggs. In consequence, the main source of the vitamins D2 and D3 is by irradiation of the corresponding pro-... 

Chloro-5 -bromotyrosine (42) was identified from hydrolysates of a sclero-protein constituting the operculum of the gastropod mollusk Baccinum undatum in 1971 34). A,A,iV-Trimethyl halogenated tyrosines, 43, 44, 45, and 46 were isolated from the Caribbean sponge Pseudoceratina crassa by Fattorusso s group 35). The absolute stereochemistries of 43 and 44 were determined to be L by Gao and Hamann 36). 

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See also in sourсe #XX -- [ ]

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