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Lactuca L. species belong to the Asteraceae family and these plants are traditionally used for therapeutic purposes around the world. The dried milky latex of L. serriola is known as &ldquo, lettuce oil&rdquo, and is used as a sedative in Turkey. This study aimed to evaluate the sedative effects and analyze the chemical compositions of latexes obtained from some Lactuca species growing in Turkey. The sedative effects were evaluated through various behavioral tests on mice. For this purpose, latexes were obtained from L. glareosa Boiss., L. viminea (L.) J. Presl and C. P, L. mulgedioides (Vis and Panćić) Boiss. and Kotschy ex. Boiss., L. saligna L., and L. serriola L. The latex from L. saligna showed the highest sedative effects, whilst L. serriola and L. viminea latexes also displayed significant sedative effects compared to the control group at a dose of 100 mg/kg. However, the latexes from L. glareosa and L. mulqedioides did not exhibit any sedative effects on mice. Characteristic sesquiterpene lactones (lactucin, lactucopicrin, 11,13&beta, dihydrolactucin, and 11,13&beta, dihydrolactucopicrin) were determined qualitatively and quantitatively by high-performance liquid chromatography (HPLC). Lactucin was identified as the main component.

Lettuce is an important annual leafy vegetable and bitterness is its potent flavor character. Lettuce germplasm differ their phenotypic characters and sesquiterpene lactones (SLs) contents which are important for consumer’s acceptance. This study was carried out to evaluate the phenotypic characters and SLs contents in one hundred lettuce germplasm in Jeonju, Korea. Twenty-three agro-morphological (16 qualitative and 7 quantitative) traits and two SLs (lactucin and lactucopicrin) contents were studied in these germplasm. Germplasm exhibited the variation in qualitative and quantitative characters. Average plant weight was 423.9 g with a range from 116.0 to 905.0 g. Lactucin content was varied from 19.7 (IT 294226) to 194.4 ㎍/g (IT 294298) with an average concentration of 84.7 ㎍/g. Lactucopicrin ranged from 82.5 (IT 300134) to 2228.6 ㎍/g (IT 294210) with an average concentration of 586.3 ㎍/g. Total SLs content was ranged from 120.1 (IT 300134) to 2286.6 (IT 294210) ㎍/g with the average concentration of 671.0 ㎍/g. Significant (p≤0.05) differences were found between crisp head and butter head germplasm for lactucin, lactucopicrin and total SLs content. Crisp head germplasm revealed the highest average lactucin (112.9 ㎍/g), lactucopicrin (734.8 ㎍/g) and total SLs content (847.7 ㎍/g). Crisp head and leafy type germplasm exhibited more total SLs content (847.7 and 744.7 ㎍/g, respectively) than cos (524.9 ㎍/g) and butter head type (519.4 ㎍/g). Principal component analyses of the quantitative traits indicated that the first principal component axis accounted more than 91% of the total variation. This study revealed the ample genetic variation in the agro-morphological traits and SLs contents to support the selection for improved lettuce varieties.

Scope Nuclear factor-κB (NF-κB) activation in macrophages aggravates atherosclerosis. Dietary plant secondary metabolites including sesquiterpene lactone lactucopicrin target multiple organs. This study was focused on the impact of lactucopicrin on NF-κB activation in inflammated macrophages and atherogenesis in a mouse model of atherosclerosis. Methods and results In LPS-stimulated mouse bone marrow-derived macrophages, lactucopicrin inhibited NF-κB activation and concomitantly repressed the expression of IL-1β, IL-6 and tumor necrosis factor alpha. This effect was not due to modulation of inhibitor of NF-κB kinases (IKK) α/β/γ and NF-κB inhibitor α, and NF-κB/p65 DNA binding activity. Instead, the lactucopicrin effect was reliant on the inhibition of cytoplasmic dynein-mediated p65 transportation, a prerequisite step for p65 nuclear translocation. In high-fat diet-fed apolipoprotein E-deficient mice, lactucopicrin consumption dose-dependently reduced plaque area, inhibited plaque macrophage accumulation, attenuated plaque macrophage NF-κB activation, and reduced both plaque and serum inflammatory burden. However, lactucopicrin consumption did not affect the levels of serum lipids and anti-inflammatory cytokines (IL-4, IL-10 and transforming growth factor beta). Conclusion Dietary lactucopicrin inhibits atherogenesis in mice likely by its anti-inflammatory property. These findings suggest that dietary supplementation with lactucopicrin is a promising strategy to inhibit atherosclerotic cardiovascular disease. This article is protected by copyright. All rights reserved.

In recent years we initiated extensive studies on the characterization of the population structure of wild Lactuca relatives (WLRs) originating from their center of origin and diversity in Southwest Asia. A comparative phytochemical study of nine sesquiterpene lactones in natural populations of the wild lettuce L. altaica Fisch. & C.A. Mey. (Asteraceae) was performed, based on 22 plants, representing seven original individual seed samples derived from three localities representing three regions in Armenia. The compounds were profiled and quantified in leaves and roots of the plants, grown in a controlled glasshouse. The contents of major sesquiterpene lactones, that including the following eight guaianolides: cichorioside B, lactucin, 11β,13-dihydrolactucin, crepidiaside B, 8-deoxylactucin, jacquinelin, lactucopicrin/11β,13-dihydrolactucopicrin, as well as the germacranolide glucoside – lactuside A, were estimated by HPLC/PDA. The L. altaica plants could be characterized by the occurrence of lactuside A in their roots, and the mixture of lactucopicrin/11β,13-dihydrolactucopicrin in both their roots and leaves by relatively high amounts, similarly to results obtained for three commercial cultivars of L. sativa. The total content of sesquiterpene lactones in the roots was significantly higher than that in the leaves. This study is likely the first report of detailed screening of L. altaica natural populations and individuals, even by low sample size, for any trait. Species within the primary lettuce gene pool, should be considered as an attractive source of germplasm in further research and improvement of cultivated lettuce, Lactuca sativa L. While using interspecific hybridization in order to elevate the sesquiterpene levels in cultivated lettuces, the lactones quality (profile) and quantity, as well as the cross-ability level of the wild Lactuca spp. with the crop and fertility of the obtained offspring should be considered.

Fresh-cut chicory was produced by four different processing lines testing cold and warm water (4/45 °C, 120 s) and cold water containing cysteine (0.5 mM) against an unwashed control. Levels of sesquiterpene lactones (SLs), sensory, and color attributes as well as O2 and CO2 levels in the modified atmosphere of the fresh-cut produce stored in consumer-sized bags (4 °C, 10 days) were monitored. All washing procedures applied significantly reduced the SL contents and bitterness in fresh-cut chicory. Warm water washing was most effective, reducing the total SL levels by 60.9-64.5%. Sensory and color attributes were also retained best by warm water washing, suggesting such treatments to be suitable measures to improve the quality and reduce the bitterness of fresh-cut chicory. SL profiles changed substantially in all samples during storage, revealing lactucopicrin to be the major SL directly after processing, whereas 11(S),13-dihydrolactuin prevailed at the end of storage.

The anthelmintic activity of chicory (Cichorium intybus L.) herbage has been attributed to sesquiterpene lactones. Chicory leaves contain significant amounts of lactucin (LAC), 8-deoxylactucin (DOL), and lactucopicrin (LPIC), but the proportions of these three sesquiterpene lactones vary among forage chicory cultivars. To determine whether the individual compounds differ in anthelmintic activity, we prepared sesquiterpene lactone-enriched extracts from leaves of two forage chicory cultivars, 'Grasslands Puna' (Puna) and 'Forage Feast', and tested their effects on the hatching of a predominantly Haemonchus contortus egg population. The dominant constituents in the Puna and Forage Feast extracts were DOL and LAC, respectively; LPIC concentrations in the two extracts were similar. Extracts from both cultivars inhibited egg hatching at all concentrations tested (P

Palatability and anthelmintic activity of chicory (Cichorium intybus L.) forage are influenced by the sesquiterpene lactones lactucin (LAC), 8-deoxylactucin (DOL) and lactucopicrin. Therefore, the objective of this study was to determine how sesquiterpene lactone concentration and composition vary during the growing season. Three forage chicory cultivars (Puna, Forage Feast and Lacerta) grown in West Virginia and Pennsylvania (USA) were managed during two consecutive years to maintain plants in the vegetative stage, and sesquiterpene lactones in leaves were quantified after each growth interval. Cultivars differed in the total concentration of sesquiterpene lactones and in the proportions of LAC and DOL. Total sesquiterpene lactone concentration generally decreased or remained constant during the season, but the specific response depended on the cultivar. Differences in seasonal patterns between years corresponded with unusual climatic conditions. The three cultivars had similar concentrations of DOL in the spring. Forage Feast provided a dramatically lower concentration of DOL during the summer. Uniformly high concentrations of DOL across the growing season in Puna and Lacerta make these cultivars attractive for use in bioactive pastures for control of Haemonchus contortus. Changes in both sesquiterpene lactone concentration and composition during the season result in large variations in forage bitterness.

Two new sesquiterpene lactones, namely 8-O-methylsenecioylaustricin (1) and epi-8 alpha-angeloyloxy-cichoralexin (2), as well as a new triterpene glycoside (taraxasterol 3-O-beta-D-glucoside, 3), together with the three known sesquiterpene lactones lactucin (4), lactucopicrin (5), and 11 beta,13-dihydrolactucin (6), were isolated from the stems of Cichorium glandulosum BOISS. FT HUET. The chemical structures were elucidated on the basis of spectroscopic methods.

none 3 no In the present study, curly endive (Cichorium endivia L. var. crispum) and escarole (Cichorium endivia L. var. latifolium) accessions were investigated for their sensory characters (bitterness, astringency and herbaceous flavour) and acceptance in relation to sesquiterpene lactone and phenolic content. Different facets of the perception of these sensory traits in relation to lactones and phenolics were brought out. Lactucopicrin and kaempferol malonyl glucoside were consistently related to bitterness, astringency and herbaceous flavour perceptions. Overall acceptance was significantly and inversely related mainly to bitterness. The generic statement that sesquiterpene lactones and phenolic compounds are determinants of bitterness and other related sensory characters does not seem to be fully consistent with our data, that indicated how the balance of different compounds affects these traits individually, in a rather complex manner, with a prevailing negative impact of phenolics. Bitter, astringent, and herbaceous perceptions were significantly affected by variety, with curly endive showing on average higher scores in comparison to escarole, with particular respect to bitterness. D'Antuono, L. Filippo; Ferioli, Federico; Manco, Manuela Agata D'Antuono, L. Filippo; Ferioli, Federico; Manco, Manuela Agata

The forage potential of chicory (Cichorium intybus L.) has not been realized in southern West Virginia (WV) because ruminants are reluctant to consume the herbage. Chicory contains bitter sesquiterpene lactones that can adversely impact palatability. This study was undertaken to determine whether sesquiterpene lactone concentrations in chicory grown in southern WV differ from those in chicory grown in central Pennsylvania (PA) where chicory is grazed readily. Herbage was collected in 1997 and 1998 from cultivars Grasslands Puna (Puna), INIA le Lacerta (Lacerta), and Forage Feast established at research sites near State College, PA, and Beckley, WV. The total concentration of sesquiterpene lactones in WV-grown cultivars was 0.58% (dry matter basis) in Puna, 0.59% in Lacerta, and 0.79% in Forage Feast in 1997 and ranged from 1.03 (Lacerta) to 1.52% (Forage Feast) in 1998. In PA-grown cultivars, sesquiterpene lactones represented 0.16 (Puna), 0.18 (Lacerta), and 0.27% (Forage Feast) of the forage dry matter in 1997 and ranged from 0.32 (Lacerta) to 0.55% (Forage Feast) in 1998. Concentrations of lactucin, lactucopicrin, and total sesquiterpene lactones in Forage Feast exceeded those in the other cultivars grown at the same site. The lowest concentrations of lactucopicrin and total sesquiterpene lactones observed among WV-grown cultivars were higher (2-fold or more) than the highest concentrations present in cultivars grown the same year in PA. Mineral analyses of soils from the two cultivation sites indicate that P availability may influence sesquiterpene lactone composition of chicory herbage. Results provide a foundation for future studies of environmental effects on sesquiterpene lactone composition and palatability of chicory herbage.

A transformed root culture of Cichorium intybus L. (Asteraceae) was found to produce sesquiterpene lactones of guaiane and germacrane type. Lactucopicrin, 8-desoxylactucin and three sesquiterpene lactone glycosides: crepidiaside B, sonchuside A and ixerisoside D were isolated from the roots. The yield of 8-desoxylactucin reached 0.03 g l-1 at the early stationary phase of the culture.

One of the quality parameters of chicory (Cichorium intybus L.) is its slightly bitter taste which is caused by sesquiterpene lactones. As the quality of chicons is highly dependent on the quality of the roots, the effects of the cultivation conditions of the roots on the levels of sesquiterpene lactones in chicons were investigated. Roots from a collection of 11 commercially available and 2 experimental chicory cultivars were grown at five different locations with two nitrogen manuring levels to evaluate the differences in sesquiterpene lactone levels as measured with enzyme-linked immunosorbent assays (ELISAs). There were significant differences (P

The bitter taste of chicory is caused by sesquiterpene lactones. The levels of lactucopicrin and lactucin-like sesquiterpene lactones, i.e. lactucin, 8-deoxylactucin and their 11β,13-dihydro derivatives, in chicons from four different chicory cultivars (Cichorium intybus L.) were determined by ELISA. Data were used to determine the sample size needed for the statistically reliable determination of the levels of sesquiterpene lactones in chicory. The sample size varied from 6 to 12 chicons. No relation between the weight of chicons and the sesquiterpene lactone levels was found. The distribution of sesquiterpene lactones in chicons from two cultivars, i.e. cv. Focus and cv. Monitor, was studied with ELISA. In both cultivars the central axis contained the major part of the sesquiterpene lactones as compared to the proximal and distal parts of the leaves. Storage at 2 °C and 10 °C for up to 13 days had no effect on the level of lactucin-like sesquiterpene lactones in the chicons. After 7 days of storage a slight increase of lactucopicrin content was observed as compared with chicons analysed after 1 and 13 days of storage.

Polyclonal antisera against lactucin and lactucopicrin, two bitter-tasting principles of chicory (Cichorium intybus L.), were obtained after immunization of rabbits with KLH−lactucin and KLH−lactucopicrin conjugates, respectively. In competitive ELISA, the sera from KLH−lactucopicrin-immunized rabbits showed a very low cross-reactivity with other sesquiterpene lactones containing a guaiane skeleton, 0.5% with lactucin, 1% with a mixture of lactucin and 11β,13-dihydrolactucin, and 5% with 8-deoxylactucin and 11β,13-dihydro-8-deoxylactucin. The sera from rabbits immunized with KLH−lactucin showed 50% cross-reaction with 8-deoxylactucin and its 11β,13-dihydro derivative and only 0.4% cross-reaction with lactucopicrin. In competitive ELISAs, chicory extracts spiked with free sesquiterpene lactones showed an expected increase in inhibition level. These ELISAs seem useful in the assessment of chicory bitterness. Keywords: Sesquiterpene lactones; chicory (Cichorium intybus); lactucin; lactucopicrin; bitter taste...

Five known and one new sesquiterpene lactones were isolated from fresh chicory roots (Cichorium intybus). The new compound 11(S),13-dihydrolactucopicrin was identified by UV, 1 H NMR, 13 C NMR, and mass spectroscopy. The extraction procedure and HPLC analysis of sesquiterpene lactones in chicory were improved. The bitterness detection thresholds of all compounds were individually determined by triangle testing

Samples of red-coloured lettuce and chicory were assessed for bitterness by sensory analysis and compared with conventional green-coloured varieties. The amounts of the sesquiterpene lactones lactucin, 8-deoxylactucin and lactucopicrin and their glycosides were determined using enzyme hydrolysis and high performance liquid chromatography. The level of each of these compounds was compared with the bitterness score found for each sample, and the resulting correlation data suggested that the increasing level of one of these compounds, lactucin glycoside, was closely related to the increase in bitterness.

Because of the skeletal complexity and similarity of the polarity, little research was reported on the isolation of sesquiterpene lactones by high-speed counter-current chromatography (HSCCC). Herein, three sesquiterpene lactones were successfully purified from the ethyl acetate extract of the roots of the traditional Uyghur medicinal plant Cichorium glandulosum Boiss. et Huet. by HSCCC. The separation was performed in two steps with two solvent systems: n-hexane-ethyl acetate-methanol-water (1.5:5:2.75:5, v/v/v/v) and ethyl acetate-methanol-water (20:1:20, v/v/v). From 166 mg of the ethyl acetate extract, 19 mg of lactucopicrin was isolated with the first solvent system and 10 mg of 11beta,13-dihydrolactucin and 16 mg of lactucin were obtained with the second solvent system. All purified compounds were over 94% purity as determined by HPLC analysis, and these chemical structures were confirmed by (1)H NMR and (13)C NMR.

Lactuca saligna and Lactuca virosa are two wild lettuce species that show multiple virus resistance, and both have been successfully used in breeding programs for the introduction of virus resistance into commercial lettuce, Lactuca sativa. These two wild Lactuca species contained three major sesquiterpene lactones, i.e. lactucin, 8-deoxylactucin, and lactucopicrin, as measured by gradient RP-HPLC. L. saligna contained 103, 372, and 79 μg/g, respectively, and L. virosa contained 257, 173, and 1733 μg/g, respectively, of these three lactones that are present in both free and glycoside bound forms. The commercial lettuce varieties Montello (L. sativa) and Saladcrisp, derived from L. sativa×L. saligna, had very low levels of lactucin and lactucopicrin and were devoid of 8-deoxylactucin. Five breeding lines of lettuce, bred from the same interspecies cross as var. Saladcrisp, were also devoid of 8-deoxylactucin and contained between 0 and 60% as much lactucin or lactucopicrin as their parent strains. One lettuce breeding line, 93-426, contained only 18 μg/g of lactucin and was devoid of both lactucopicrin and 8-deoxylactucin, but this line is resistant to three viruses. This suggests that the level and types of these sesquiterpenene lactones present in lettuce have little effect on virus resistance. Nevertheless, lettuce breeders using wild Lactuca as resistant parents should be cognizant of their high levels of sesquiterpene lactones

One new alkylresorcinol derivative, cichoriol B, and a mixture of three other ones, cichoriols A, C, and D, were isolated from the dichloromethane extract of Cichorium spinosum, a plant that is used traditionally in the Cretan diet. The methanol extract afforded one new sesquiterpene lactone, (4R)-3,4-dihydrolactucopicrin. The structures of the new compounds were determined by spectroscopic methods, mainly by the concerted application of 1D and 2D NMR techniques (HMQC, HMBC, NOESY).

Wounding leaves or stems of Lactuca species releases a milky latex onto the plant surface. We have examined the constituents of latex from Lactuca sativa (lettuce) cv. Diana. The major components were shown to be novel 15-oxalyl and 8-sulfate conjugates of the guaianolide sesquiterpene lactones, lactucin, deoxylactucin, and lactucopicrin. The oxalates were unstable, reverting to the parent sesquiterpene lactone on hydrolysis. Oxalyl derivatives have been reported rarely from natural sources. The sulfates were stable and are the first reported sesquiterpene sulfates from plants. Unusual tannins based on 4-hydroxyphenylacetyl conjugates of glucose were also identified. Significant qualitative and quantitative variation was found in sesquiterpene lactone profiles in different lettuce varieties and in other Lactuca spp. The proportions of each conjugate in latex also changed depending on the stage of plant development. A similar profile was found in chicory, in which oxalyl conjugates were identified, but the 8-sulfate conjugates were notably absent. The presence of the constitutive sesquiterpene lactones was not correlated with resistance to pathogens but may have a significant bearing on the molecular basis of the bitter taste of lettuce and related species. The induced sesquiterpene lactone phytoalexin, lettucenin A, was found in the Lactuca spp. but not in chicory.

The solubility of lactucin, 8-deoxylactucin and lactucopicrin, all sesquiterpene lactones of chicory roots, was determined as a function of pH (pH 1–10) in the presence and absence of polysaccharides. The stability of the sesquiterpene lactones, when dissolved in water, decreased under influence of daylight as a function of pH. Enzymatic hydrolysis of lactucopicrin by commercial enzyme preparations, used for liquefaction of chicory roots into lactucin and p-hydroxyphenylacetic acid, was not found.

The release of lactucin, 8-deoxylactucin and lactucopicrin, all sesquiterpene lactones, which are bitter constituents of chicory, has been studied during enzymatic liquefaction of chicory roots with commercial pectolytic and cellulolytic enzymes at 40 °C for 24 h. After 5–8 h most of these bitter compounds are found in the liquid phase (supernatant) and not in the sediment (residue), except for lactucopicrin, which ist hardly soluble in aqueous solution.

8-Deoxylactucin, lactucin and lactupicrin were isolated from Cichorium intybus . 8-Deoxylactucin and jacquilenin were isolated from Leontodon autumnalis and were found in particular abundance in flowers of the latter species. Flowers of L. autumnalis do not produce pentacyclic triterpenoid diols. Thus this species is the first noted exception to the Zimmermann rule, which correlates the co-occurrence of triterpenoid diols and carotenoids in flowers of Compositae plants.

Four new sesquiterpene lactones, cichoriolide A and cichoriosides A, B and C, have been isolated from Cichorium endivia L. and C. intybus L., together with nine known sesquiterpene lactones. The structures of the new compounds were established on the basis of chemical and spectral data. Further, the cytotoxic activities of related glycosides and the aglycones were compared in the L-5178Y cultured cell system.