The dynamic variations of flavonoid metabolites in flower buds for Zingiber mioga at different developmental stages

Zingiber mioga Roscoe, a perennial herb, is favoured by consumers for its unique flavor and purplish-red appearance. Studies have shown flavonoids, such as anthocyanins, procyanidins, flavonols and flavones, have a great influence on its appearance quality, flavor formation and physiological function. The production and accumulation of those metabolites are particularly closely related to the appearance formation of Z. mioga flower buds. Therefore, the changes in the relative content of anthocyanins, procyanidins and other flavonoids in flower buds of Z. mioga during the whole developmental stage were studied. More importantly, we depicted the association landscape between anthocyanins and procyanidins as well as other flavonoids such as flavones, flavonols and flavanols, which were natural plant compounds that affected the appearance quality and nutritional value of Z. mioga. The results showed that the total anthocyanins and most anthocyanins and procyanidins, as well as the other flavonoids, all reached the highest value at the maturity stage. Among these secondary metabolites, the quercetin-3-O-(2''-O-rhamnosyl) galactoside, quercetin-4′-O-glucuronide, quercetin-3-O-neohesperidoside and sexangularetin-3-O-glucoside-7-O-rhamnoside in flavonoids, the delphinidin-3-O-glucoside, petunidin-3-O-rutinoside, delphinidin-3-O-(6''-O-p-coumaroyl) glucoside and petunidin-3-O-(6''-O-p-coumaroyl) glucoside in anthocyanins, and procyanidin B2 in procyanidins played a major role in these changes in the enhancement of appearance quality and physiological function during its growth. Furthermore, anthocyanins might synergize with procyanidins and other flavonoids to jointly affect the color formation of flower buds in Z. mioga at the development and maturity stages.