Flavonoid in the context of "Medicago"

Anthocyanins (from Ancient Greek ἄνθος (ánthos) 'flower' and κυάνεος/κυανοῦς (kuáneos/kuanoûs) 'dark blue'), also called anthocyans, are water-soluble vacuolar pigments that, depending on their pH, may appear red, pink, purple, blue, or black. In 1835, the German pharmacist Ludwig Clamor Marquart named a chemical compound that gives flowers a blue color, Anthokyan, in his treatise "Die Farben der Blüthen" (English: The Colors of Flowers). Food plants rich in anthocyanins include the blueberry, raspberry, black rice, and black soybean, among many others that are red, pink, blue, purple, or black. Some of the colors of autumn leaves are derived from anthocyanins.

Anthocyanins belong to a parent class of molecules called flavonoids synthesized via the phenylpropanoid pathway. They can occur in all tissues of higher plants, including leaves, stems, roots, flowers, and fruits. Anthocyanins are derived from anthocyanidins by adding sugars. They are odorless and moderately astringent.

In biochemistry, naturally occurring phenols are natural products containing at least one phenol functional group. Phenolic compounds are produced by plants and microorganisms. Organisms sometimes synthesize phenolic compounds in response to ecological pressures such as pathogen and insect attack, UV radiation and wounding. As they are present in food consumed in human diets and in plants used in traditional medicine of several cultures, their role in human health and disease is a subject of research. Some phenols are germicidal and are used in formulating disinfectants.

Polyphenols (/ˌpɒliˈfiːnoʊl, -nɒl/) are a large family of naturally occurring phenols. They are abundant in plants and structurally diverse. Polyphenols include phenolic acids, flavonoids, tannic acid, and ellagitannin, some of which have been used historically as dyes and for tanning garments.

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.

Flavan-3-ols (sometimes referred to as flavanols) are a subgroup of flavonoids. They are derivatives of flavans that possess a 2-phenyl-3,4-dihydro-2H-chromen-3-ol skeleton. Flavan-3-ols are structurally diverse and include a range of compounds, such as catechin, epicatechin gallate, epigallocatechin, epigallocatechin gallate, proanthocyanidins, theaflavins, thearubigins. They play a part in plant defense and are present in the majority of plants.