日本語版

lactucopicrin

compound / compound-lactucopicrin

ラクチュコピクリン

Lactucopicrin is a sesquiterpene lactone found in chicory.

Photographs (captions in Japanese)

A photograph of a whole chicory plant with many blue-violet flowers in bloom

A whole flowering plant of chicory (Cichorium intybus). Lactucopicrin is a sesquiterpene lactone found in this plant, and this is a photograph of the source plant, not of the compound itself.

Raw materialShown: Cichorium intybus (chicory)Part / state: Whole plant in flower

Photo: NY State IPM Program at Cornell University from New York, USA / CC BY 2.0 / original image / ledger's original image

Scope and provenance of the photo

Identification: Identified as labelled in the source. A different file from the photographs used for ingredient-chicory and compound-lactucin (to avoid duplication).

Image shown: The full-size file from Wikimedia Commons. No cropping or color changes by NIGAMI LAB. For display, a WebP capped at 1200 px wide is served; the ledger's original image can be checked from the link above.

On this page (10 sections)
  1. Overview
  2. Sources for this overview (3)
  3. Topic hubs
  4. Follow the connections
  5. Related entries (10)
  6. Measured values (1)
  7. Composition and content (2)
  8. Sensory (3)
  9. Mechanism and receptors (2)
  10. How processing and cooking change it (1)
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Reading the bitterness

Lactucopicrin is a sesquiterpene lactone contained in the root of chicory (Cichorium intybus). It has been reported to exist at concentrations of 11.93±0.46 micromolar per gram in raw root, 10.66±0.94 micromolar in roasted chicory-substitute coffee powder, and 0.45±0.04 micromolar in its extract. It was not detected in roasted regular coffee.

Among the lactones derived from chicory that were compared in the same study, lactucopicrin elicited the strongest bitter-receptor response. It activated the human bitter receptor TAS2R43 at a threshold of 0.1 micromolar and an EC50 of 0.46±0.08 micromolar, and TAS2R46 at a threshold of 0.03 micromolar and an EC50 of 0.35±0.06 micromolar; the response to TAS2R14 was only minimal, with a threshold of 30 micromolar. However, TAS2R46 is a receptor that has been shown in separate research to respond broadly to sesquiterpene lactones in general, and this high potency does not necessarily indicate selective binding to lactucopicrin. Additionally, despite its lower concentration on a per-gram basis than lactucin, its effect on receptors was far stronger; the authors caution that reordering chicory's bitter compounds by concentration alone is misleading.

The lactucopicrin concentration in chicory extract (0.45 micromolar) exceeds the receptor threshold but remains near the EC50 level, and sensory testing is still needed to directly link it to the intensity of bitterness actually perceived. An independent research group also confirmed lactucopicrin as the major sesquiterpene lactone in fresh-cut witloof chicory immediately after processing, and reported that its composition changes with storage.

Sources for this overview

  1. Overlapping activation pattern of bitter taste receptors affect sensory adaptation and food perception

    Lang R; Lang T; Dunkel A; Ziegler F; Behrens M / 2022 / journal article / full text checked

    Checked for this overview: Concentrations in 3 forms—raw root, powder, and extract—and non-detection in roasted coffee. / Thresholds and EC50 values for TAS2R43, TAS2R46, and TAS2R14 activation; caution regarding the mismatch between concentration and potency. / Confirmation that extract concentration exceeds threshold but remains near EC50.

  2. Broad tuning of the human bitter taste receptor hTAS2R46 to various sesquiterpene lactones, clerodane and labdane diterpenoids, strychnine, and denatonium

    Brockhoff A; Behrens M; Massarotti A; Appendino G; Meyerhof W / 2007 / journal article / abstract checked

    Checked for this overview: Confirmation that TAS2R46 responds broadly to sesquiterpene lactones in general.

  3. Sesquiterpene lactone content and overall quality of fresh-cut witloof chicory (Cichorium intybus L. var. foliosum Hegi) as affected by different washing procedures

    Wulfkuehler S; Gras C; Carle R / 2013 / journal article / abstract checked

    Checked for this overview: Independent group's confirmation in fresh-cut witloof, and composition changes with storage.

Follow the connections

lactucopicrin →activates→ TAS2R46

lactucopicrin →contributes to→ bitterness →can be measured separately …→ astringency

chicory →contains→ lactucopicrin

Measured values (1)

KindCompoundTargetValueConditionsSource
receptor EC50lactucopicrinTAS2R460.35±0.06 µMHEK293 cell assayLang R, 2022

Values are the reported values of each source (with units and conditions). Thresholds and EC50 depend on the panel and method; they are not single true values.

Structured claims — open a section to read each claim's confidence, evidence and limits

Composition and content (2)

chicory contains lactucopicrinsupported

Scope: Chicory and chicory-based coffee substitute in the cited research

Note: Concentration varies with the material and preparation.

Lactucopicrin was quantified at 11.93 +/- 0.46 umol/g in fresh chicory (fresh weight; plant part not stated), 10.66 +/- 0.94 umol/g in roasted chicory coffee-substitute powder (per weight of dry powder), and 0.45 +/- 0.04 uM in the prepared coffee-substitute extract; it was not detected in roasted coffee.
Limitations: A single set of samples and a single processing route. Fresh chicory and the coffee-substitute powder are on different weight bases, and this is not a comparison of the same material before and after roasting. Whether its ranking relative to lactucin changes with product or process was not examined in this source (the ledger covers that in a separate evidence row).
Source: Overlapping activation pattern of bitter taste receptors affect sensory adaptation and food perception (Lang R; Lang T; Dunkel A; Ziegler F; Behrens M, 2022) · full text checked
An independent group that quantified sesquiterpene lactones in freshly-cut witloof chicory reports lactucopicrin as the major sesquiterpene lactone right after processing, confirming its presence in chicory outside the Lang 2022 dataset.
Limitations: Absolute concentrations are not captured from the abstract; this corroborates presence and relative ranking, not the Lang 2022 figures. It differs from Lang 2022's roasted chicory in plant part and product form (freshly-cut witloof).
Source: Sesquiterpene lactone content and overall quality of fresh-cut witloof chicory (Cichorium intybus L. var. foliosum Hegi) as affected by different washing procedures (Wulfkuehler S; Gras C; Carle R, 2013) · abstract checked
Show dataingredient-chicory —contains→ compound-lactucopicrin
claim: clm-chicory-contains-lactucopicrin / type: composition / updated: 2026-08-30
witloof chicory contains lactucopicrinsupported

Scope: Fresh-cut witloof chicory

Note: Reported as the major sesquiterpene lactone immediately after processing.

In fresh-cut witloof immediately after processing, lactucopicrin was the major sesquiterpene lactone.
Limitations: Only the abstract was checked; absolute concentrations were not obtained.
Source: Sesquiterpene lactone content and overall quality of fresh-cut witloof chicory (Cichorium intybus L. var. foliosum Hegi) as affected by different washing procedures (Wulfkuehler S; Gras C; Carle R, 2013) · abstract checked
Show dataingredient-witloof-chicory —contains→ compound-lactucopicrin
claim: clm-witloof-lactucopicrin / type: composition / updated: 2026-08-31

Sensory (3)

lactucopicrin contributes to bitternesssupported

Scope: Chicory and chicory-based coffee substitute in the cited research

Note: Receptor activation together with the concentration in the food forms perception.

Lactucopicrin is present at 11.93 +/- 0.46 umol/g in fresh chicory (fresh weight; Table 2 does not state the plant part, and the fresh chicory used in the sensory test was leaves), 10.66 +/- 0.94 umol/g in coffee-substitute powder, and 0.45 +/- 0.04 uM in the coffee-substitute extract, and is the most potent of the chicory lactones tested: TAS2R43 EC50 0.46 +/- 0.08 uM (threshold 0.1 uM), TAS2R46 EC50 0.35 +/- 0.06 uM (threshold 0.03 uM). It also showed a minimal response at TAS2R14, with a threshold of 30 uM.
Limitations: Its molar concentration is lower than lactucin's, but it is far more potent, so ranking chicory's bitter compounds by concentration alone is misleading. The extract concentration (0.45 uM) exceeds the receptor threshold and sits near the EC50, but extrapolating to perceived intensity still requires sensory data (this study's sensory test did not separately measure this compound's own contribution).
Source: Overlapping activation pattern of bitter taste receptors affect sensory adaptation and food perception (Lang R; Lang T; Dunkel A; Ziegler F; Behrens M, 2022) · full text checked
Show datacompound-lactucopicrin —contributes_to→ sensation-bitter
claim: clm-lactucopicrin-bitter / type: sensory / updated: 2026-08-30
curly endive — perceived bitterness is associated with: lactucopicrinsupported

Scope: Sensory evaluation (bitterness, astringency, herbaceous flavor, overall preference) and chemical analysis correlation study on a germplasm collection of Cichorium endivia var. crispum (curly endive) and var. latifolium (escarole).

Note: According to the abstract, 2 compounds—lactucopicrin and kaempferol malonyl glucoside—were consistently related to perceptions of bitterness, astringency, and herbaceous flavor. Overall preference showed a significant negative correlation primarily with bitterness. Significant differences in bitterness, astringency, and herbaceous flavor were found among varieties, with curly endive scoring on average higher than escarole, particularly notably so for bitterness. The abstract also notes that the general statement 『セスキテルペンラクトンとフェノールが苦味等の決定要因』 (in translation: "sesquiterpene lactones and phenolics are determinants of bitterness and the like") is not fully consistent with the data, and that the balance of compounds has a complex effect (with a dominant negative contribution from phenolics).

The paper reports that lactucopicrin and kaempferol malonyl glucoside were consistently related to perceptions of bitterness, astringency, and herbaceous flavour. Bitter, astringent, and herbaceous perceptions were significantly affected by variety, with curly endive showing on average higher scores than escarole, particularly for bitterness.
Limitations: Only the abstract was checked (full text not confirmed). Specific correlation coefficients, statistical values, and panel size are not in the abstract.
Source: The impact of sesquiterpene lactones and phenolics on sensory attributes: An investigation of a curly endive and escarole germplasm collection (Filippo D'Antuono, L.; Ferioli, F.; Manco, M. A., 2016) · abstract checked
Show dataingredient-endive —has_perceived_bitterness_associated_with→ compound-lactucopicrin
claim: clm-w40-endive-escarole-bitterness-sensory / type: sensory / updated: 2026-09-02
lactucopicrin has a reported human taste threshold of 0.5 ppm (cited from an earlier report). The precursor lactucopicrin 15-oxalate (LO) was perceived as equally bitter at roughly 10 times the concentration of L, and its threshold was estimated to be higher than 5 ppm (because the authentic standard of LO contains 5% L, its precise threshold could not be measured, and it is also possible that L formed from LO in the mouth)preliminary

Scope: Horie 2011, the 「lactucopicrins の苦味強度」 (in translation: "Bitterness intensity of lactucopicrins") section. A sensory comparison of authentic standards (the number of panelists and the scale are not given)

Note: The authors infer that LO's own bitterness is extremely weak compared to L. The 0.5 ppm threshold is cited from reference 3 and is not a measurement from this paper.

L's threshold has been reported as 0.5 ppm (reference 3). The authentic standard of LO was perceived as equally bitter at roughly 10 times the concentration of L, and LO's threshold was estimated to be a higher concentration than 5 ppm. Because the authentic standard of LO contains 5% L, and there is a strong possibility that L formed in the mouth during the threshold evaluation, the authors judged that measuring LO's own threshold is extremely difficult.
Limitations: The number of panelists, the scale, and statistics are not given. LO's threshold is an estimate.
Source: ドレッシングの使用がキク科野菜の苦味を緩和する (堀江 秀樹, 2011) · full text checked
Show datacompound-lactucopicrin —has_reported_human_taste_threshold_of→ (the claim sentence above)
claim: clm-w176-lactucopicrin-oxalate-weaker-bitterness / type: sensory / updated: 2026-09-26

Mechanism and receptors (2)

lactucopicrin activates TAS2R46supported

Scope: Receptor assay in a cultured-cell system, in the cited study

Note: The same paper also reports overlapping receptor activation by other chicory lactones.

Lactucopicrin activated TAS2R46 with a threshold of 0.03 uM and an EC50 of 0.35 +/- 0.06 uM, the most sensitive receptor-compound pair reported in this study; lactucin activated the same receptor with a threshold of 1 uM and an EC50 of 8.85 +/- 1.17 uM. 11beta,13-dihydrolactucin had a threshold of 30 uM, and no EC50 was determined within the concentration range tested.
Limitations: The EC50 values are based on Table 1, not on statements in the body text. This receptor responded to all 3 compounds tested in this study (lactucopicrin, lactucin and 11beta,13-dihydrolactucin), so its high sensitivity to lactucopicrin is not evidence of selectivity for that compound alone.
Source: Overlapping activation pattern of bitter taste receptors affect sensory adaptation and food perception (Lang R; Lang T; Dunkel A; Ziegler F; Behrens M, 2022) · full text checked
Context: Independently characterizes hTAS2R46 as a receptor that responds broadly not only to sesquiterpene lactones but also to clerodane- and labdane-type diterpenoids, strychnine, and denatonium; its first deorphanization was with the sesquiterpene lactone herbolide D. Because lactucopicrin belongs to the sesquiterpene lactones, the Lang 2022 result falls within an agonist class already established for this receptor.
Limitations: Lactucopicrin and lactucin themselves are not named in the abstract, nor are they shown to have been tested; this is class-level corroboration, not a direct replication. Broad tuning also cuts the other way: a receptor that responds to many sesquiterpene lactones is weaker evidence of selectivity for lactucopicrin specifically. Abstract-level extraction, with no potency figures.
Source: Broad tuning of the human bitter taste receptor hTAS2R46 to various sesquiterpene lactones, clerodane and labdane diterpenoids, strychnine, and denatonium (Brockhoff A; Behrens M; Massarotti A; Appendino G; Meyerhof W, 2007) · abstract checked
Show datacompound-lactucopicrin —activates→ receptor-tas2r46
claim: clm-chicory-tas2r46 / type: mechanism / updated: 2026-08-30
lactucopicrin is derived from Breakdown of lactucopicrin 15-oxalate (LO). When endive leaves were blended and extracted in buffers at pH 5.5, 6.5, and 7.5, the proportion of L in the L+LO total was 1% or less, 4%, and 9%; at pH 7.5, LO decreased and L increased over time after extraction. This suggested that formation of L from LO is promoted under neutral to weakly alkaline conditions (the authors' wording)preliminary

Scope: Horie 2011, Figure 1. Endive leaves blended and extracted for 3 minutes with 9 times their weight of 0.1 M phosphate buffer, n=3

Note: When the latex of lettuce and endive is analyzed quickly, L is 1% or less of the total (endive 0.9%, lettuce 0.6%), and the authors caution that L can also form from LO during sample preparation for analysis. (2026-10-21, expansion stage N5 stage C batch 5: Codex's check against the source confirmed that the authors stop at calling formation from LO "suggested" on the basis of observations in buffer (n=3); lowered from supported to preliminary.)

The proportion of L (L/(L+LO)) in the extracts obtained with buffers at pH 5.5, 6.5, and 7.5 was 1% or less, 4%, and 9%. At pH 7.5, a decrease in LO and an increase in L were observed over time after extraction, suggesting that the formation of L from LO is promoted under weakly alkaline conditions.
Limitations: This is a result in buffer, and does not include oral conditions (temperature, saliva components).
Source: ドレッシングの使用がキク科野菜の苦味を緩和する (堀江 秀樹, 2011) · full text checked
Show datacompound-lactucopicrin —is_derived_from→ (the claim sentence above)
claim: clm-w176-lactucopicrin-formed-from-oxalate-ph-dependent / type: mechanism / updated: 2026-10-21

How processing and cooking change it (1)

witloof chicory forcing increases lactucopicrinsupported

Scope: Residual root-stock (FR) tissue following forcing; cv. Sweet Lady; 12 months storage.

Note: Same as above.

In residual root-stock (FR) tissue following forcing, lactucopicrin increased from 31.5±9.5 to 75.8±1.5 μg/g DW.
Limitations: Same as above.
Source: Effect of Root Storage and Forcing on the Carbohydrate and Secondary Metabolite Composition of Belgian Endive (Cichorium intybus L. Var. foliosum) (van Arkel J; Twarogowska A; Cornelis Y; De Marez T; Engel J; Maenhout P; de Vos RCH; Beekwilder J; Van Droogenbroeck B; Cankar K, 2022) · full text checked
Show dataprocess-witloof-forcing —increases→ compound-lactucopicrin
claim: clm-w37c-witloof-forcing-increases-lactucopicrin / type: processing / updated: 2026-09-02

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