Variation of Sesquiterpene Lactones Content in Lactuca and Cichorium Species

Abstract

Lettuce (Lactuca spp.) and chicory (Cichorium spp.) are known as traditional medicinal plants with several pharmaceutical effects attributed to the sesquiterpene lactones (SLs) present in their latex. Genetic variations of SL concns. in lettuce and chicory were investigated using HPLC from the perspective of lettuce breeding to obtain higher SL concns. Lettuce cultivars (L. sativa L.) showed lower SL concns. than wild Lactuca species and cultivated Cichorium species. It is assumed that breeding efforts for better taste with little bitterness in cultivated lettuce resulted in low SLs concns. because SLs are primary components of bitterness in Lactuca and Cichorium. Intraspecific variation of SL concns. among 3 morphol. types of cultivated lettuce was obsd. and lines of crisp-head type, a most popular head formation type, showed a lower SL concn. than those of the leaf-type and cos-type. A few lines with high SL concns. found in this expt. are available to breed lettuce with a high SL concn. [on SciFinder(R)]