A Biliviolin Metal Complex in Ox Bile

Abstract

AN ethyl acetate extract of fresh ox bile acidified to 5 per cent with concentrated hydrochloric acid yielded a dark green waxy solid on taking to dryness in vacuo. Chromatography of this substance from a 2 : 10 methanol–ether solution on a column consisting of a mixture of 12 gm. of acid-washed talc and 3 gm. ‘Hyflo’ filter-aid gave a single grey-green band which could be partly eluted with methanol. The absorption spectrum of the eluted substance (a green solid) in methanol and in methanolic hydrochloric acid is shown in the accompanying figure. Acidification changed the colour of the solution from green to violet and shifted the absorption maximum from 646 to 568 mμ A chloroform solution of the compound showed a strong red fluorescence in ultraviolet light. The pigment could not be extracted from chloroform solution with 1 per cent hydrochloric acid, demonstrating that it was biliviolin and not a bilipurpurin complex.