Picrocrocin is a monoterpene glycoside precursor of safranal. It is found in the spice saffron, which comes from the crocus flower. Picrocrocin has a bitter taste, and is the chemical most responsible for the taste of saffron.
During the drying process, picrocrocin liberates the aglycone (HTCC, C10H16O2) due to the action of the enzyme glucosidase. The aglycone is then transformed to safranal by dehydration. Picrocrocin is a degradation product of the carotenoid zeaxanthin.
Anthocyanidins are common plant pigments, the aglycones of anthocyanins. They are based on the flavylium cation, an oxonium ion, with various groups substituted for its hydrogen atoms. They generally change color from red through purple, blue, and bluish green as a function of pH.
Anthocyanidins are an important subclass of the polymethine dyes and flavonoids. The flavylium cation is a chromenylium cation with a phenyl group substituted in position 2; and chromenylium (also called benzopyrylium) is a bicyclic version of pyrylium. The positive charge can move around the molecule.