Fig. 7: Overview of araloside structures and their biosynthesis in A. elata.

The light-yellow box indicates the cyclization of 2,3-oxidosqualene to β-amyrin and CYP-catalyzed hydroxylation of triterpenoids. The boxes in other colors represent the glycosylation of different triterpene backbones. Brown letters indicate hydroxylation reactions catalyzed by cytochrome P450 monooxygenases (P450s); blue letters indicate glycosylation reactions catalyzed by cellulose synthase-like glycosyltransferase (CSL); green letters indicate C28 glycosylation reactions catalyzed by UDP-dependent glycosyltransferases (UGTs); and purple letters indicate C3–2 glycosylation reactions catalyzed by UGTs. Reaction sites are indicated in the corresponding colors. Broken arrows indicate putative araloside biosynthesis steps.