8-Deoxylactucin

8-Deoxylactucin at a Glance

8-Deoxylactucin is a bitter guaianolide sesquiterpene lactone — one of the three principal lactones of chicory (Cichorium intybus) root, alongside lactucin and lactucopicrin. Structurally it is lactucin minus a single oxygen: the C-8 hydroxyl is absent, which is the whole of the difference and the reason for the name.

Its interest is unusual for a minor plant lactone. Across four independent research groups working on completely different endpoints — COX-2 suppression, nitric-oxide production, nematode paralysis, and a full anti-inflammatory structure–activity screen — bio-guided fractionation of chicory has repeatedly converged on 8-deoxylactucin as the most active compound in the extract ^{2,4,5,9Reference 2Zhou Y et al. · 2025Sesquiterpene lactones from Cichorium intybus exhibit potent anti-inflammatory and hepatoprotective effects by repression of NF-κB and enhancement of NRF2View study →Reference 4Cavin C et al. · 2005Inhibition of the expression and activity of cyclooxygenase-2 by chicory extractView study →Reference 5Valente AH et al. · 2021Identification of compounds responsible for the anthelmintic effects of chicory (Cichorium intybus) by molecular networking and bio-guided fractionationView study →Reference 9Harmatha J et al. · 2024Inhibitory effect of selected guaianolide and germacranolide sesquiterpene lactones on nitric oxide productionView study →}. That convergence, rather than any single dramatic result, is the case for taking it seriously.

It has a second life as an agricultural nuisance. Chicory is grown industrially for inulin, and these lactones are the reason the root tastes bitter; a substantial breeding and gene-editing literature exists on turning their production up or down ^{11,12,13Reference 11Cankar K et al. · 2023Lactucin synthase inactivation boosts the accumulation of anti-inflammatory 8-deoxylactucin and its derivatives in chicory (Cichorium intybus L.)View study →Reference 12Cankar K et al. · 2022CRISPR/Cas9 targeted inactivation of the kauniolide synthase in chicory results in accumulation of costunolide and its conjugates in taprootsView study →Reference 13Bogdanović M et al. · 2020Silencing of germacrene A synthase genes reduces guaianolide oxalate content in Cichorium intybus LView study →}. The same molecule is therefore simultaneously a wanted bioactive and an unwanted flavour defect.

There is no human data of any kind on the isolated compound, and — as the next section sets out — it is not a wild-lettuce molecule.

Is It Actually a Wild-Lettuce Compound?

This page was commissioned from a wild-lettuce (Lactuca virosa) research note. The attribution does not survive checking, and the honest answer is that 8-deoxylactucin is a chicory compound.

The check is simple enough to reproduce. As of 31 July 2026, PubMed returns 26 records for deoxylactucin and 21 records for "Lactuca virosa". The two sets do not intersect at a single record, and the direct query deoxylactucin AND virosa returns zero. Every paper in which the isolated molecule is assayed uses Cichorium intybus, Cichorium bottae, or Lactuca sativa — never L. virosa.

The likely origin of the mix-up is visible in the literature itself. The one study that frames these guaianolides as wild-lettuce compounds — Wesołowska and colleagues’ mouse analgesia work — describes its test compounds as “characteristic bitter sesquiterpene lactones of Lactuca virosa and Cichorium intybus” ^{19Reference 19Wesołowska A et al. · 2006AnimalAnalgesic and sedative activities of lactucin and some lactucin-like guaianolides in miceView study →}. But the three compounds it actually tested were lactucin, lactucopicrin and 11β,13-dihydrolactucin. 8-Deoxylactucin was not among them. It appears to have been absorbed into the wild-lettuce story by association with its better-studied siblings, which genuinely are shared between the two plants.

Two further cautions belong here, because this is exactly the kind of compound that attracts silent contamination:

• The genus is not the species. Deoxylactucin-type conjugates are documented from Lactuca latex — Sessa and colleagues profiled L. sativa cv. Diana and other Lactuca species and found oxalate and sulfate conjugates of lactucin, deoxylactucin and lactucopicrin ^{16Reference 16Sessa RA et al. · 2000Metabolite profiling of sesquiterpene lactones from Lactuca speciesView study →}. So the compound class is real in lettuce. That is not the same as a primary report placing 8-deoxylactucin in L. virosa, which the indexed record does not contain. A trace presence in wild lettuce is plausible; it is simply undocumented.
• The sulfate-conjugate names are not interchangeable. The lettuce literature reports both a 15-deoxylactucin-8-sulfate and an 8-deoxylactucin-15-sulfate ^{15,16Reference 15Chadwick M et al. · 2016Perception of bitterness, sweetness and liking of different genotypes of lettuceView study →Reference 16Sessa RA et al. · 2000Metabolite profiling of sesquiterpene lactones from Lactuca speciesView study →}. These cannot both be conjugates of the molecule here: 8-deoxylactucin has no oxygen at C-8 at all (its systematic name retains only the C-15 hydroxymethyl), so no 8-sulfate ester of it can exist. At least one of those names refers to a different isomer. Any figure quoted for a “deoxylactucin sulfate” in lettuce should be traced to its structure before it is attached to this compound.

Nothing else here is a wild-lettuce finding. Where wild lettuce is relevant, it is as the plant that does contain lactucin and lactucopicrin — see wild lettuce.

The α-Methylene-γ-Lactone Question

Most sesquiterpene lactones owe their reactivity to an exocyclic α-methylene group on the lactone ring, a Michael acceptor that alkylates cysteine thiols. Because that warhead hits NF-κB, iNOS, and a long list of other thiol-dependent targets, “inhibits NF-κB in vitro” is close to uninformative about any individual member of the class. So the first question about any sesquiterpene lactone is whether it has the group at all — several well-known ones do not.

8-Deoxylactucin does have it. Its structure carries the exocyclic methylene on the γ-lactone (systematic name: 3-methylidene-..-azuleno[4,5-b]furan-2,7-dione; C₁₅H₁₆O₄, MW 260.28), exactly as lactucin (C₁₅H₁₆O₅) does — the two differ only by the C-8 hydroxyl. The 11β,13-dihydro derivatives that also occur in chicory are the ones with the methylene saturated away ^{6,8Reference 6Peña-Espinoza M et al. · 2015In vitroSesquiterpene lactone containing extracts from two cultivars of forage chicory (Cichorium intybus) show distinctive chemical profiles and in vitro activity against Ostertagia ostertagiView study →Reference 8Mares D et al. · 2005Chicory extracts from Cichorium intybus L. as potential antifungalsView study →}. And the structure–activity analysis in the largest screen of chicory lactones to date confirmed the moiety is required for the anti-inflammatory effect across the series ^{2Reference 2Zhou Y et al. · 2025Sesquiterpene lactones from Cichorium intybus exhibit potent anti-inflammatory and hepatoprotective effects by repression of NF-κB and enhancement of NRF2View study →}.

So the default reading applies: most of what 8-deoxylactucin does in a cell is class reactivity, not a private property. Its NF-κB suppression, its iNOS and COX-2 effects, and its cytotoxicity toward parasites are all things a competent Michael acceptor does.

What is genuinely specific to this molecule is narrower, and more interesting: it consistently outperforms its own near-identical siblings. Lactucin and lactucopicrin carry the same warhead and co-occur in the same tissue, yet four unrelated groups found 8-deoxylactucin the stronger of them:

Study	Endpoint	Result
Zhou 2025 2Reference 2Zhou Y et al. · 2025Sesquiterpene lactones from Cichorium intybus exhibit potent anti-inflammatory and hepatoprotective effects by repression of NF-κB and enhancement of NRF2View study →	Anti-inflammatory screen of 18 chicory lactones	8-deoxylactucin the most potent component
Harmatha 2024 9Reference 9Harmatha J et al. · 2024Inhibitory effect of selected guaianolide and germacranolide sesquiterpene lactones on nitric oxide productionView study →	Nitric-oxide production, mouse peritoneal cells	8-deoxylactucin “the apparently most active substance”
Valente 2021 5Reference 5Valente AH et al. · 2021Identification of compounds responsible for the anthelmintic effects of chicory (Cichorium intybus) by molecular networking and bio-guided fractionationView study →	Anthelmintic bio-guided fractionation	8-DOL “most strongly associated with anti-parasitic activity”
Foster 2011 7Reference 7Foster JG et al. · 2011In vitroIn vitro analysis of the anthelmintic activity of forage chicory (Cichorium intybus L.) sesquiterpene lactones against a predominantly Haemonchus contortus egg populationView study →	Haemonchus contortus egg hatch	DOL-rich extract EC₅₀ 2.6 mg/mL vs lactucin-rich 6.4 mg/mL; “LAC has minimal effect”

A reasonable hypothesis is that removing the C-8 hydroxyl raises lipophilicity and membrane access without touching the warhead — but that is a hypothesis. No one has tested it directly, and the one endpoint where the ranking reverses is acetylcholinesterase, where lactucopicrin is twice as potent ^{1Reference 1Rollinger JM et al. · 2005Application of the in combo screening approach for the discovery of non-alkaloid acetylcholinesterase inhibitors from Cichorium intybusView study →}. The ordering is target-dependent, and should not be generalised into “8-deoxylactucin is the strong one.”

What It's Used For

All of it is preclinical. The anti-inflammatory work is the only strand with an animal result for the isolate; everything else is in vitro or extract-level.

Evidence by IndicationStrength of support · Beta

Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. Nothing here rises above preclinical, so read the ceilings rather than the ranks.

01Anti-inflammatory / hepatoprotectivePromising48%Isolate, mouse in vivo + three independent in-vitro labs; iNOS IC₅₀ 6.8 µM ^{2,3,4,9Reference 2Zhou Y et al. · 2025Sesquiterpene lactones from Cichorium intybus exhibit potent anti-inflammatory and hepatoprotective effects by repression of NF-κB and enhancement of NRF2View study →Reference 3Elbermawi A et al. · 2024Phytochemical analysis of Cichorium bottae root and anti-inflammatory potential assessment of isolatesView study →Reference 4Cavin C et al. · 2005Inhibition of the expression and activity of cyclooxygenase-2 by chicory extractView study →Reference 9Harmatha J et al. · 2024Inhibitory effect of selected guaianolide and germacranolide sesquiterpene lactones on nitric oxide productionView study →}

02Anthelmintic (livestock nematodes)Shaky38%Three in-vitro studies, bio-guided; extract-level EC₅₀s, explicitly synergistic ^{5,6,7Reference 5Valente AH et al. · 2021Identification of compounds responsible for the anthelmintic effects of chicory (Cichorium intybus) by molecular networking and bio-guided fractionationView study →Reference 6Peña-Espinoza M et al. · 2015In vitroSesquiterpene lactone containing extracts from two cultivars of forage chicory (Cichorium intybus) show distinctive chemical profiles and in vitro activity against Ostertagia ostertagiView study →Reference 7Foster JG et al. · 2011In vitroIn vitro analysis of the anthelmintic activity of forage chicory (Cichorium intybus L.) sesquiterpene lactones against a predominantly Haemonchus contortus egg populationView study →}

03Acetylcholinesterase inhibitionShaky18%One in-vitro chicory screen; IC₅₀ 308 µM — very weak, and weaker than lactucopicrin ^{1Reference 1Rollinger JM et al. · 2005Application of the in combo screening approach for the discovery of non-alkaloid acetylcholinesterase inhibitors from Cichorium intybusView study →}

04Antifungal (dermatophytes)Shaky14%One study; activity correlated with lactone content in extracts, not an isolate assay ^{8Reference 8Mares D et al. · 2005Chicory extracts from Cichorium intybus L. as potential antifungalsView study →}

Mechanisms

The load-bearing caveat: rows 1–5 are what any α-methylene sesquiterpene lactone does. The compound-specific finding is that 8-deoxylactucin sits at the potent end of its own structural series on inflammation and parasites, and at the weak end on cholinesterase.

Pharmacokinetics

There is no pharmacokinetic study of 8-deoxylactucin in any species. No absorption, oral bioavailability, Cmax, volume of distribution, protein binding, half-life, or CYP profile has been measured, and no validated bioanalytical method for it in plasma has been published. That absence is the page’s binding constraint: the anti-inflammatory figures are single-digit micromolar and the cholinesterase figure is 308 µM, and nothing establishes that either concentration is reachable in a human.

What does exist is gut-microbiota metabolism data for the class, which is directly relevant and mostly bad news for the parent compound. In vitro faecal fermentation and a human feeding study showed dietary sesquiterpene lactones from lettuce and escarole are extensively catabolised by gut bacteria, chiefly by dehydroxylation and double-bond hydrogenation; deoxylactucin was detected as one of the products of lactucopicrin metabolism, and phase-II glucuronide and sulfate conjugates of deoxylactucin and related metabolites appeared in volunteers’ urine with “large inter-subject variability” ^{17Reference 17García CJ et al. · 2020In vitroHuman gut microbiota metabolism of dietary sesquiterpene lactones: untargeted metabolomics study of lactucopicrin and lactucin conversion in vitro and in vivoView study →}. Two consequences follow. First, the double-bond hydrogenation reported there is precisely the reaction that would destroy the α-methylene warhead, converting the compound to its inactive dihydro form. Second, 8-deoxylactucin is not only an intake but a metabolite — a mouse study found faecal 8-deoxylactucin rose after probiotic administration ^{21Reference 21Dai W et al. · 2024AnimalBacteroides salyersiae is a candidate probiotic species with potential anti-colitis properties in the human colon: first evidence from an in vivo mouse modelView study →} — so its concentration in the gut is partly a microbiome variable rather than a dose variable.

Clinical Trials

None. 8-Deoxylactucin has never been administered to humans as an isolated compound, and no registered trial has studied it. There is no standardised chicory preparation that specifies its content — commercial chicory breeding runs in the opposite direction, selecting for less of it ^{13Reference 13Bogdanović M et al. · 2020Silencing of germacrene A synthase genes reduces guaianolide oxalate content in Cichorium intybus LView study →}.

Last checked: July 2026.

Isolate vs. Plant Studies

This molecule sits in an unusually clean position on the isolate question, and it is worth stating precisely because the surrounding literature is full of whole-extract claims.

The anti-inflammatory strand is genuine isolate work. The compound was purified and assayed as a single substance in all four supporting papers, and the mouse hepatitis experiment dosed the isolate ^{2,3,4,9Reference 2Zhou Y et al. · 2025Sesquiterpene lactones from Cichorium intybus exhibit potent anti-inflammatory and hepatoprotective effects by repression of NF-κB and enhancement of NRF2View study →Reference 3Elbermawi A et al. · 2024Phytochemical analysis of Cichorium bottae root and anti-inflammatory potential assessment of isolatesView study →Reference 4Cavin C et al. · 2005Inhibition of the expression and activity of cyclooxygenase-2 by chicory extractView study →Reference 9Harmatha J et al. · 2024Inhibitory effect of selected guaianolide and germacranolide sesquiterpene lactones on nitric oxide productionView study →}. That is a real strength, and it is why this application scores highest.

The anthelmintic strand is not. Despite being framed as compound identification, every potency number belongs to a cultivar extract characterised by its lactone profile ^{6,7Reference 6Peña-Espinoza M et al. · 2015In vitroSesquiterpene lactone containing extracts from two cultivars of forage chicory (Cichorium intybus) show distinctive chemical profiles and in vitro activity against Ostertagia ostertagiView study →Reference 7Foster JG et al. · 2011In vitroIn vitro analysis of the anthelmintic activity of forage chicory (Cichorium intybus L.) sesquiterpene lactones against a predominantly Haemonchus contortus egg populationView study →}; the one paper that did proper bio-guided fractionation concluded 8-DOL works synergistically with other sesquiterpene lactones rather than alone ^{5Reference 5Valente AH et al. · 2021Identification of compounds responsible for the anthelmintic effects of chicory (Cichorium intybus) by molecular networking and bio-guided fractionationView study →}. Any statement of the form “8-deoxylactucin is an anthelmintic at X concentration” is currently unsupported.

The antifungal strand is extract-only ^{8Reference 8Mares D et al. · 2005Chicory extracts from Cichorium intybus L. as potential antifungalsView study →}, and the acetylcholinesterase result, while isolate-based, is a single unreplicated in-vitro screen at a concentration with no physiological meaning ^{1Reference 1Rollinger JM et al. · 2005Application of the in combo screening approach for the discovery of non-alkaloid acetylcholinesterase inhibitors from Cichorium intybusView study →}.

Two further disciplines matter for this compound specifically. Species discipline: the pharmacology is chicory pharmacology, and importing it into a wild-lettuce context is the error to correct — see above. Sibling discipline: 8-deoxylactucin, lactucin and lactucopicrin are almost always reported as a set, and their numbers are easily transposed. The figures here belong to 8-deoxylactucin alone; where a comparison is made, the sibling’s figure is given alongside it.

Finally, one published result has been withdrawn. A 2019 paper reporting antitumour effects of 8-deoxylactucin in RB355 retinoblastoma cells was retracted in 2021 for non-original and manipulated figures ^{23Reference 23Retraction · 2021Retracted: antitumor effects of 8-deoxylactucin in RB355 human retinoblastoma cells are mediated via apoptosis induction, reactive oxygen species production, and cell cycle arrestView study →}. It is excluded from the evidence above and should not be cited.

Bitterness & The Chicory Breeding Problem

Chicory’s economic value is inulin, a dietary fibre and sugar substitute extracted from the taproot — and 8-deoxylactucin is one of the reasons that root tastes bitter. The compound therefore has a substantial applied-genetics literature written from the perspective of wanting less of it.

In the root the lactones are mostly not free: NMR profiling of sugarloaf chicory confirmed that the major root lactones — lactucin, 8-deoxylactucin and lactucopicrin — occur as 15-oxalate conjugates, which are markedly more water-soluble than the parent compounds and therefore follow the inulin into the extract ^{20Reference 20Scioli G et al. · 2026Metabolic profiling of sugarloaf chicory roots: structural assignment of sesquiterpene lactone conjugates and response to reduced irrigationView study →}. The same study found all three conjugates fell by 39–50% under reduced irrigation, so bitterness is also an environmental variable, not only a genetic one ^{20Reference 20Scioli G et al. · 2026Metabolic profiling of sugarloaf chicory roots: structural assignment of sesquiterpene lactone conjugates and response to reduced irrigationView study →}.

The genetic work has run in both directions, and it is the clearest demonstration of where this molecule sits in the pathway:

• Silencing germacrene A synthase (CiGASlo/CiGASsh), the committed first step, reduces guaianolide oxalate content overall — the blunt approach to de-bittering ^{13Reference 13Bogdanović M et al. · 2020Silencing of germacrene A synthase genes reduces guaianolide oxalate content in Cichorium intybus LView study →}.
• Knocking out kauniolide synthase by CRISPR/Cas9 blocks the pathway further downstream, causing costunolide and its conjugates to pile up in the taproot instead ^{12Reference 12Cankar K et al. · 2022CRISPR/Cas9 targeted inactivation of the kauniolide synthase in chicory results in accumulation of costunolide and its conjugates in taprootsView study →}.
• Knocking out lactucin synthase (CYP71DD33) does the opposite of de-bittering and is the most informative result here: because that enzyme hydroxylates C-8 to make lactucin, removing it diverts flux into 8-deoxylactucin and its derivatives, which accumulate strongly ^{11Reference 11Cankar K et al. · 2023Lactucin synthase inactivation boosts the accumulation of anti-inflammatory 8-deoxylactucin and its derivatives in chicory (Cichorium intybus L.)View study →}. The paper’s framing is telling — it treats the enriched 8-deoxylactucin lines as a route to an anti-inflammatory product, not a flavour problem.

For flavour research the relevant conjugate is a sulfate rather than an oxalate: in a lettuce sensory-genetics study, 8-deoxylactucin-15-sulphate was among the compounds contributing most to perceived bitterness across genotypes, with the bitter-to-sweet compound ratio the key determinant of both bitterness and liking ^{15Reference 15Chadwick M et al. · 2016Perception of bitterness, sweetness and liking of different genotypes of lettuceView study →}. (See the naming caution in the attribution section above before transferring that figure to the free lactone.)

Prevalence in Nature

8-Deoxylactucin is a Cichorieae compound — the chicory/lettuce tribe of the Asteraceae — and is not reported broadly outside it.

Its principal documented source is the root of chicory (Cichorium intybus), where it is one of the three main bitter guaianolides alongside lactucin and lactucopicrin; leaves contain them too, but the roots are described as carrying the high concentrations ^{14Reference 14de Kraker JW et al. · 1998de Kraker JW, Franssen MC, de Groot A, König WA, Bouwmeester HJ (1998). (+)-Germacrene A biosynthesis. The committed step in the biosynthesis of bitter sesquiterpene lactones in chicory. Plant Physiology. https://pubmed.ncbi.nlm.nih.gov/9701594/View study →}. It occurs there predominantly as the 15-oxalate conjugate ^{20Reference 20Scioli G et al. · 2026Metabolic profiling of sugarloaf chicory roots: structural assignment of sesquiterpene lactone conjugates and response to reduced irrigationView study →}. A second Cichorium species, C. bottae, yields it from the root as well ^{3Reference 3Elbermawi A et al. · 2024Phytochemical analysis of Cichorium bottae root and anti-inflammatory potential assessment of isolatesView study →}. Within Lactuca, deoxylactucin-type oxalate and sulfate conjugates are documented from the latex of garden lettuce (Lactuca sativa) and other Lactuca species ^{16Reference 16Sessa RA et al. · 2000Metabolite profiling of sesquiterpene lactones from Lactuca speciesView study →}, and 8-deoxylactucin-15-sulphate is a bitterness contributor across lettuce genotypes ^{15Reference 15Chadwick M et al. · 2016Perception of bitterness, sweetness and liking of different genotypes of lettuceView study →} — but, as set out above, wild lettuce (L. virosa) is not a documented source.

Quantitatively the record is poor. No absolute concentration for 8-deoxylactucin in field-grown chicory root has been located in a form usable for comparison — the recent profiling work reports relative changes rather than mg/g ^{20Reference 20Scioli G et al. · 2026Metabolic profiling of sugarloaf chicory roots: structural assignment of sesquiterpene lactone conjugates and response to reduced irrigationView study →}, and the anthelmintic literature reports whole-extract lactone content rather than compound concentration ^{6,7Reference 6Peña-Espinoza M et al. · 2015In vitroSesquiterpene lactone containing extracts from two cultivars of forage chicory (Cichorium intybus) show distinctive chemical profiles and in vitro activity against Ostertagia ostertagiView study →Reference 7Foster JG et al. · 2011In vitroIn vitro analysis of the anthelmintic activity of forage chicory (Cichorium intybus L.) sesquiterpene lactones against a predominantly Haemonchus contortus egg populationView study →}. The one hard figure available comes from cultured tissue rather than a plant: in long-term chicory hairy-root culture, the glucoside 8-deoxylactucin glucoside (crepidiaside A) was the major sesquiterpene lactone, reaching 1.4% of dry weight — reported as nearly two orders of magnitude above wild plants ^{18Reference 18Malarz J et al. · 2013Long-term cultured hairy roots of chicory — a rich source of hydroxycinnamates and 8-deoxylactucin glucosideView study →}. That figure describes an engineered production system and should not be read as a natural abundance.

Content is also not stable: drought cut the root lactone conjugates by 39–50% in one cultivar ^{20Reference 20Scioli G et al. · 2026Metabolic profiling of sugarloaf chicory roots: structural assignment of sesquiterpene lactone conjugates and response to reduced irrigationView study →}, and cultivar differences in the forage-chicory literature are large enough that Puna and Forage Feast are treated as chemically distinct chemotypes, one DOL-dominant and one lactucin-dominant ^{7Reference 7Foster JG et al. · 2011In vitroIn vitro analysis of the anthelmintic activity of forage chicory (Cichorium intybus L.) sesquiterpene lactones against a predominantly Haemonchus contortus egg populationView study →}.

Discovery & Synthesis

First isolation is not well documented. No primary isolation report for 8-deoxylactucin is retrievable in the indexed literature; the compound entered the record as one of a cluster of chicory bitter principles characterised alongside lactucin and lactucopicrin, and by 1998 it was being described without introduction as one of the “bitter sesquiterpene lactones such as the guaianolides lactupicrin, lactucin, and 8-deoxylactucin” found in chicory leaves and roots ^{14Reference 14de Kraker JW et al. · 1998de Kraker JW, Franssen MC, de Groot A, König WA, Bouwmeester HJ (1998). (+)-Germacrene A biosynthesis. The committed step in the biosynthesis of bitter sesquiterpene lactones in chicory. Plant Physiology. https://pubmed.ncbi.nlm.nih.gov/9701594/View study →}. The name is purely descriptive: it is lactucin lacking the oxygen at C-8.

Biosynthesis is, by contrast, unusually well mapped — chicory has served as the model system for guaianolide biosynthesis. The committed step is the cyclisation of farnesyl diphosphate to (+)-germacrene A by germacrene A synthase, isolated from chicory roots in 1998, which confirmed the mevalonate → farnesyl diphosphate → germacradiene route ^{14Reference 14de Kraker JW et al. · 1998de Kraker JW, Franssen MC, de Groot A, König WA, Bouwmeester HJ (1998). (+)-Germacrene A biosynthesis. The committed step in the biosynthesis of bitter sesquiterpene lactones in chicory. Plant Physiology. https://pubmed.ncbi.nlm.nih.gov/9701594/View study →}. Downstream, kauniolide synthase forms the guaianolide skeleton ^{12Reference 12Cankar K et al. · 2022CRISPR/Cas9 targeted inactivation of the kauniolide synthase in chicory results in accumulation of costunolide and its conjugates in taprootsView study →}, and lactucin synthase (CYP71DD33) performs the C-8 hydroxylation that converts 8-deoxylactucin into lactucin ^{11Reference 11Cankar K et al. · 2023Lactucin synthase inactivation boosts the accumulation of anti-inflammatory 8-deoxylactucin and its derivatives in chicory (Cichorium intybus L.)View study →}. That last enzyme places this molecule precisely: 8-deoxylactucin is the direct biosynthetic precursor of lactucin, which is why disabling the enzyme causes it to accumulate ^{11Reference 11Cankar K et al. · 2023Lactucin synthase inactivation boosts the accumulation of anti-inflammatory 8-deoxylactucin and its derivatives in chicory (Cichorium intybus L.)View study →}.

No total synthesis of 8-deoxylactucin is documented, and none would be commercially motivated. Production today is by extraction from chicory root — supercritical CO₂ extraction has been developed specifically to recover the anti-inflammatory lactone fraction ^{10Reference 10Baixinho JP et al. · 2021Supercritical CO₂ extraction as a tool to isolate anti-inflammatory sesquiterpene lactones from Cichorium intybus L. rootsView study →} — or by biotechnological routes: hairy-root culture accumulates the glucoside to 1.4% dry weight ^{18Reference 18Malarz J et al. · 2013Long-term cultured hairy roots of chicory — a rich source of hydroxycinnamates and 8-deoxylactucin glucosideView study →}, and CRISPR lactucin-synthase knockout lines were built expressly to enrich the taproot in this compound ^{11Reference 11Cankar K et al. · 2023Lactucin synthase inactivation boosts the accumulation of anti-inflammatory 8-deoxylactucin and its derivatives in chicory (Cichorium intybus L.)View study →}. There is no commercial supply of it as a nutraceutical ingredient.

Patents: not yet researched.

Toxicity & Safety

8-Deoxylactucin carries a low flag, with the emphasis on how little is known rather than on demonstrated safety. It occurs in chicory and lettuce, both eaten routinely, and no toxicity signal has emerged from that dietary exposure. But the isolated compound has never been given to a human, and no toxicology package exists for it — no acute or repeat-dose study, no genotoxicity assay, no reproductive study, in any species. Low here means unremarkable-in-food, not characterised-and-cleared.

Two structural cautions are worth stating explicitly.

It is a Michael acceptor. The α-methylene-γ-lactone that drives the pharmacology alkylates cysteine thiols indiscriminately, which is the mechanism behind sesquiterpene-lactone contact allergy and behind the cytotoxicity of the more aggressive members of the class. 8-Deoxylactucin has not been implicated in harm at dietary levels, but the reactive group is present and the concentrated compound should not be assumed benign on the strength of chicory being a salad vegetable.

Asteraceae contact dermatitis applies at the class level. Sesquiterpene lactones are the principal allergens of the daisy family, and chicory and lettuce sit within it. One point of testing practice matters here and is frequently misread: the standard sesquiterpene-lactone patch-test mix contains only alantolactone, costunolide and dehydrocostus lactone ^{22Reference 22Paulsen E et al. · 2001Sensitization and cross-reaction patterns in Danish Compositae-allergic patientsView study →}. 8-Deoxylactucin is not in it. A negative SL-mix patch test therefore excludes nothing about sensitisation to this compound — and the same study noted that most lettuce-sensitised patients were picked up by the Compositae mix rather than the SL mix, and that 19% of occupationally sensitised patients were negative to both, “making very aimed patch testing necessary” ^{22Reference 22Paulsen E et al. · 2001Sensitization and cross-reaction patterns in Danish Compositae-allergic patientsView study →}.

Interactions have not been assessed. No CYP inhibition or induction data, no transporter (P-gp) data, and no drug-interaction study of any kind exists for this molecule. The gut-microbiota finding that the class is extensively catabolised and conjugated with large inter-individual variation ^{17Reference 17García CJ et al. · 2020In vitroHuman gut microbiota metabolism of dietary sesquiterpene lactones: untargeted metabolomics study of lactucopicrin and lactucin conversion in vitro and in vivoView study →} means exposure would be unpredictable even if a dose were defined.

Safety at a Glance

✅ Low / no toxicity

• Dietary exposure is routine and unremarkable. Present in chicory and lettuce, both widely eaten, with no toxicity signal from food use.
• Reactive α-methylene-γ-lactone. A cysteine-thiol alkylator; the concentrated isolate should not inherit the safety record of the salad vegetable.
• Asteraceae contact allergy is a class risk, and the standard SL-mix patch test does not contain this compound — a negative mix result excludes nothing here ^{22Reference 22Paulsen E et al. · 2001Sensitization and cross-reaction patterns in Danish Compositae-allergic patientsView study →}.
• No toxicology of any kind for the isolate. No acute, repeat-dose, genotoxicity or reproductive study in any species; no human exposure.
• No interaction data. No CYP, transporter or drug-interaction work; gut-microbial metabolism of the class is extensive and highly variable between people ^{17Reference 17García CJ et al. · 2020In vitroHuman gut microbiota metabolism of dietary sesquiterpene lactones: untargeted metabolomics study of lactucopicrin and lactucin conversion in vitro and in vivoView study →}.

Dosage

There is no dose. 8-Deoxylactucin has never been administered to a person as an isolated compound, no clinical trial has studied it, and no chicory or lettuce product is standardised to its content. Commercial chicory breeding actively selects against it, because in an inulin crop it is a bitterness defect rather than a desired active ^{13Reference 13Bogdanović M et al. · 2020Silencing of germacrene A synthase genes reduces guaianolide oxalate content in Cichorium intybus LView study →}.

The figures that exist are research concentrations and animal doses, listed only so they are not mistaken for human guidance:

Because no pharmacokinetic study exists, none of these concentrations has been shown to be achievable in a living human, and the gap between the 6.8 µM and 308 µM figures spans the entire plausible-to-implausible range. These are doses and concentrations used in research and are not a personal recommendation.

References

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