FIGURE 3.

The biosynthetic pathway for phenols in Dendrobium officinale. The biosynthesis for main phenols includes anthocyanidins, isoflavonoids, flavones, flavonols and bibenzyls from phenylalanine. 4CL, 4-coumarate-CoA ligase; ANR, anthocyanidin reductase; ANS, anthocyanidin synthase; AT, acyltransferase; BBS, bibenzyl synthase; C3′H, 5-O-(4-coumaroyl)-D-quinate 3′-monooxygenase; C4H, cinnamate 4-hydroxylase; CCoAOMT, caffeoyl-CoA O-methyltransferase; CHI, chalcone isomerase; CHS, chalcone synthase; CYP450, cytochrome P450-dependent monooxygenase; DFR, dihydroflavonol-4-reductase; F3′5′H, flavonoid 3′,5′-hydroxylase; F3′H, flavonoid 3′-monooxygenase; F3H, flavonoid 3-hydroxylase; FLS, flavonol synthase; GT, glycosyltransferase; HCT, quinate O-hydroxycinnamoyltransferase; HI4OMT, hydroxy-isoflavanone-4- O-methyltransferases; HIDH, tri-hydroxy-isoflavanone dehydratase; LAR, leucoanthocyanidin dioxygenase; MT, methyltransferase; PAL, phenylalanine ammonia lyase.