Epimeric 3,3′-dihydroxy-ε,ε-carotenes from the skin of the yellow Costa Rican frog, Atelopus chiriquiensis

Two epimeric 3,3′-dihydroxy-ε,ε-carotenes have been identified from the skins of the yellow Costa Rican frog, Atelopus chiriquiensis; both compounds have the (6R,6′R,3′S) stereochemistry but differ in absolute configuration at C-3.