Figure 1: C. asiatica sapogenins and in vivo functional analysis of C. asiatica CYP716s.

(a) Examples of oleanane- and ursane-type sapogenins found in C. asiatica. (b) Overlay of GC–MS total ion current chromatograms showing accumulation of standard compounds and triterpenoids produced in yeast strains expressing single C. asiatica CYP716s. (c) Overlay of GC–MS total ion current chromatograms showing accumulation of standard compounds and triterpenoids produced in yeast strains expressing C. asiatica CYP716s in combination with CYP716A83. Annotated triterpenoid peaks are indicated with numbers: (1) β-amyrin, (2) erythrodiol, (3) oleanolic acid, (4) oleanolic aldehyde (which co-elutes with a nonspecific peak), (5) 6β-hydroxy β-amyrin, (6) maslinic acid, (7) putative incompletely derivatized 6β-hydroxy oleanolic acid and (8) 6β-hydroxy maslinic acid. (d) Proposed biosynthetic pathway of sapogenins in C. asiatica. Arrows of higher weight reflect the preferred order of reactions in the biosynthetic pathway, as supported by the semi-quantitative analysis shown in Table 1.