With an analytical method and authentic standards for the 7S stereoisomers in hand, the product profile of CrISY was assigned. In addition to cis–trans nepetalactols and cis—trans iridodials, the expected on-pathway intermediates for iridoid biosynthesis in Catharanthus, a number of other nepetalactol and iridodial diastereomers were observed. According to integrals of GC-MS peaks, combined cis–trans, trans–trans, trans—cis, and cis–cis species make up ∼69%, 21%, 5%, and 5% of the cyclized reaction products, respectively, under these in vitro assay conditions (Fig. 3b). Additionally, a substantial percentage of the entire product mix is reduced, non-cyclized S-8-oxocitronellal, as reported earlier (23%) (11).