Biosynthetic studies of lactucin derivatives in hairy root cultures of Lactuca floridana

Biosynthetic studies of the guaianolide-type sesquiterpene lactones 11βH,13-dihydrolactucin-8-O-acetate and 8-desoxylactucin were performed in Agrobacterium rhizogenes—transformed hairy root cultures of blue-flowered lettuce, Lactuca floridana. The ¹³C NMR spectra of the two guaianolides labelled by incorporation of [1-¹³C], [2-¹³C], [1,2-¹³C₂]acetate and [2-¹³C]mevalolactone showed patterns of enrichment consistent with a previously proposed biogenetic pathway for guaianolide-type sesquiterpene lactones via the acetate-mevalonate-germacradiene route.