anthocyanidinsanthocyanins

Anthocyanidins and anthocyanins are related flavonoid pigments that give many plants their red, purple, and blue colors. Anthocyanidins are the aglycone (non-sugar) forms, while anthocyanins are glycosides in which a sugar moiety is bound to the anthocyanidin. The six most common anthocyanidins in nature are cyanidin, delphinidin, pelargonidin, peonidin, malvidin, and petunidin. Anthocyanins occur widely in fruits, vegetables, flowers, and grains, including berries, grapes, red cabbage, and purple corn.

Anthocyanins and their aglycones are water-soluble pigments stored in plant vacuoles. Their color is highly pH-dependent: they tend to appear red in acidic conditions and blue or purple as pH increases. Chemically, glycosylation and further modifications (methylation, acylation) generate a diverse range of anthocyanins; glycosylation enhances water solubility and stability in plants, while the aglycones are generally less stable in aqueous environments.

Biological and nutritional aspects are often studied for their potential antioxidant activity and effects on inflammation. In vitro assays show antioxidant properties, and some observational studies associate high intake of anthocyanin-rich foods with health benefits. However, evidence from human clinical trials is inconsistent, and bioavailability is influenced by metabolism, food matrix, and rapid elimination.

Applications include the use of anthocyanins as natural food colorants (approved in some jurisdictions as E163). They are sensitive to heat, light, pH shifts, and metal ions, which can alter color and potency during processing and storage.

In summary, anthocyanidins are the aglycone constituents of the anthocyanin pigments, while anthocyanins are their glycoside forms responsible for much of the red-to-blue coloration in plants.