Niacin (vitamin B3)

Though niacin or nicotinic acid has been known  to the organic chemists  since  1867 and Funk isolated  it from yeast and rice polishing in order to identify  the anti-beriberi vitamin  in  1913, it was finally  isolated  as nicotinamide from  liver by Elvehjem  and his co-workers  in  1937. This was actually after  the discovery by Rum  and Smith  in 1934 that  the crude extract of  liver was  effective against pellagra (you might know that  pellagra  is  the disease condition caused  due to the deficiency of niacin  in  the body)