Yerba mate contains a variety of polyphenols such as the flavonoids quercetin and rutin. Two flavonoids, quercetin and rutin, have also been implicated as thiamine antagonists. Some versions include calcium, glucosamine, quercetin or lycopene. Quercitrin is a glycoside formed from the flavonoid quercetin and the deoxy sugar rhamnose. Its main active ingredients are lapachol, quercetin, and other flavonoids. In muscadine skins, ellagic acid, myricetin, quercetin, kaempferol, and trans-resveratrol are major phenolics. Quercetin is a flavonoid widely distributed in nature. The plant also contains flavonoids, such as quercetin, isorhamnetin, and kaempferol. Other components include three kinds of flavonoids, known as kaempferol, quercetin, and myricetin. The main constituents of chamomile flowers are polyphenol compounds, including apigenin, quercetin, patuletin, and luteolin. Flavonols, the original bioflavonoids such as quercetin, are also found ubiquitously, but in lesser quantities. Other flavonoids present in "P. incarnata" include chrysin, apigenin, luteolin, quercetin, kaempferol, and isovitexin. Other compounds detected in Bignoniaceae include verbascosides, cornoside, quercetin, ursolic acid, and saponins. This enzyme hydrolyzes the glycoside quercitrin to release quercetin and -rhamnose. Minor UV blockers include quercetin 7-"O"-glycoside, quercetin itself, kaempferol glycoside, and feruloyl ester.