Fig. 3: Sea cucumbers synthesize diverse triterpene saponins and unusual sterols.
From: Biosynthesis of saponin defensive compounds in sea cucumbers

Roles of PS, LDS and C7D in the biosynthesis of unusual sterols (Δ7(8) and Δ9(11)) and triterpene saponins (Δ7(8) and Δ9(11)). The different colored arrows represent taxa-specific sterol- or saponin-biosynthetic routes. Solid and dashed arrows represent single and multi-step reactions, respectively.