The biosynthesis of iridoid glucosides from 8-epi-deoxyloganic acid

species. Similar findings have previously been reported for M. piperita (Bricout & Paupardin, 1975) and M. rotundifolia (Bricout et al., 1978). Many of the calluses accumulate only the early precursors of the monoterpenes (namely geraniol, linalol and lavandulol), but some species give rise to cultures that accumulate monoterpenes characteristic of the intact plant. For example, cell lines from M. spicata x suaueolens accumulate carvone (the major terpene component of both the intact plant and the parent M. spicata) and sesquiterpenes. Maximum accumulation occurs in late exponential phase cells, but accumulation is appreciably higher in liquid suspension cultures than in the corresponding calluses. Supplementation of the growth medium with citric, fumaric, malic or pyruvic acids leads to a general, but small, enhancement of monoterpene accumulation. In some instances,