guizotia oleifera/tyrosine

Brown pigment(s) formed in Cryptococcus neoformans when grown on media containing extracts of the seeds of Guizotia abyssinica cannot be extracted by common organic solvents or by 6 n HCl or 2 n NaOH. A similar pigmentation was observed in C. neoformans when grown on a medium containing caffeic acid

When 2,3- or 3,4-dihydroxybenzoic acid, 3,4-dihydroxyphenylalanine, and 3,4-dihydroxycinnamic acid are added to growth media, they are converted to a characteristic brown pigment by Cryptococcus neoformans. This pigment formation has hitherto been encountered only when this microorganism was