| Abstract: | 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 isolated from the hydrolyzed methanol extract of G. abyssinica seeds. Its methyl ester and the diacetate thereof, as well as the following structurally related compounds, 3-hydroxytyramine, 3,4-dihydroxybenzoic acid, 3,4-dihydroxyphenylethanolamine, and 4-hydroxy-3,5-dimethoxycinnamic acid, brought about similar pigmentation. However, 2,4-, 2,5-, 2,6-, and 3,5-dihydroxybenzoic acids, tyrosine, phenylalanine, cinnamic acid, 4-hydroxycinnamic acid, and 4-hydroxy-3-methoxycinnamic acid did not cause coloration in C. neoformans. |
