Compound Monograph
2-Hydroxymethylanthraquinone
2-Hydroxymethylanthraquinone is a simple anthraquinone from the inner bark of pau d'arco (Tabebuia/Handroanthus), where it co-occurs with the better-studied naphthoquinones lapachol and beta-lapachone. Its one real isolate signal is in-vitro antibacterial activity against Helicobacter pylori; there is no human data on the pure compound.
Sources · 3
Where Does It Come From?
2-Hydroxymethylanthraquinone is a naturally occurring anthraquinone (simple, non-hydroxylated), found in Pau d'arco and 2 other sources. It is well tolerated orally (low toxicity).
Concentration
Content by Source
Concentrations not reported. No percent-dry-weight or mg/g figures have been published for this compound in its source plants.
2-Hydroxymethylanthraquinone at a Glance
2-Hydroxymethylanthraquinone is a simple anthraquinone — an anthraquinone core carrying a single hydroxymethyl (–CH2OH) group and none of the ring hydroxyls that define the emodin-type pigments. It is best known as a minor constituent of the inner bark of pau d’arco (lapacho/taheebo; Tabebuia impetiginosa, syn. Handroanthus impetiginosus), and it also occurs in teak (Tectona grandis) heartwood and in Morinda roots 1,
Two honesty points frame everything below. First, it is not a laxative anthraquinone: the purgative anthranoids of senna, rhubarb and cascara are hydroxylated glycosides (sennosides, anthrone glycosides), a different structural sub-class — this molecule carries no such activity. Second, pau d’arco’s medicinal reputation rests on its naphthoquinones, lapachol and beta-lapachone, not on its anthraquinones; this compound is a bystander among the more-studied quinones, and its own isolate data are sparse 5Reference 5ReviewTabebuia impetiginosa: a comprehensive review on traditional uses, phytochemistry, and immunopharmacological properties — reviewView study →.
The single genuine signal for the pure molecule is in-vitro antibacterial activity against Helicobacter pylori, where an isolate from taheebo bark out-performed metronidazole in a MIC assay 1Reference 1In vitroAntibacterial activity of Tabebuia impetiginosa Martius ex DC (taheebo) against Helicobacter pylori — in vitroView study →. There is no human data on the isolated compound.
A Pau d’Arco Anthraquinone
Pau d’arco’s chemistry is dominated by quinones, but of two structural kinds. The headline actives are naphthoquinones — lapachol (the defining marker) and beta-lapachone (the basis of the synthetic oncology analogue ARQ 761) — which carry most of the herb’s antimicrobial and anticancer literature 5Reference 5ReviewTabebuia impetiginosa: a comprehensive review on traditional uses, phytochemistry, and immunopharmacological properties — reviewView study →. Alongside them the bark holds a smaller set of anthraquinones, of which 2-hydroxymethylanthraquinone and anthraquinone-2-carboxylic acid are the named examples 1Reference 1In vitroAntibacterial activity of Tabebuia impetiginosa Martius ex DC (taheebo) against Helicobacter pylori — in vitroView study →.
The one study that puts this molecule at centre stage is Park et al. (2006), who fractionated taheebo inner bark for anti-Helicobacter activity. Three compounds carried it — lapachol, anthraquinone-2-carboxylic acid, and 2-hydroxymethylanthraquinone, the most potent of the set (MIC 2 µg/mL versus 32 µg/mL for metronidazole) 1Reference 1In vitroAntibacterial activity of Tabebuia impetiginosa Martius ex DC (taheebo) against Helicobacter pylori — in vitroView study →. That is a real, isolate-level result, but it is a single in-vitro report; nothing has followed it into an animal infection model, let alone a person.
Its wider quinone family shows what the scaffold can do — structure-activity work on pau d’arco naphthoquinones confirms the quinone core drives the antimicrobial effect 6Reference 6In vitroStructure-activity relationship studies of antimicrobial naphthoquinones derived from constituents of Tabebuia avellanedae — in vitroView study → — but that is the class, not this compound. For the isolated molecule the honest verdict is: one promising antibacterial screen, a scatter of cytotoxicity data pointing both ways, and no clinical evidence at all.
What It's Used For
The evidence base for isolated 2-hydroxymethylanthraquinone is a handful of in-vitro assays plus one dated animal antileukemic screen. Read every row as isolate, preclinical, single-study.
Support is an experimental score — weighted by study type (human > animal > in vitro) and volume. A beta, not a validated metric. All rows here are isolated-compound, preclinical, and rest on one or two studies, so scores stay low by design.
The one application where the isolated molecule is itself the tested agent. Bioassay-guided fractionation of Tabebuia impetiginosa (taheebo) dried inner bark for anti-Helicobacter pylori activity yielded three actives; 2-hydroxymethylanthraquinone was the most potent, with a MIC of 2 µg/mL against H. pylori — roughly sixteen-fold lower than metronidazole’s 32 µg/mL in the same panel (though still well above the reference antibiotics amoxicillin and tetracycline) 1Reference 1In vitroAntibacterial activity of Tabebuia impetiginosa Martius ex DC (taheebo) against Helicobacter pylori — in vitroView study →.
The authors flagged it specifically as meriting further study as an H. pylori-eradicating lead 1Reference 1In vitroAntibacterial activity of Tabebuia impetiginosa Martius ex DC (taheebo) against Helicobacter pylori — in vitroView study →.
Gap: this is a single in-vitro MIC study. There is no in-vivo infection model, no oral-exposure or pharmacokinetic work, and no human data — so the result cannot be read as clinical efficacy for the compound or for pau d’arco.
The signals here disagree. In an older bioassay-directed study of Morinda parvifolia, 2-hydroxymethylanthraquinone was one of the isolated anthraquinones and registered activity in the P-388 mouse lymphocytic leukemia screen 2Reference 2Cytotoxic antileukemic anthraquinones from Morinda parvifolia.
A modern synthesis-and-screening paper, however, placed it among the weakly cytotoxic analogues — IC50 near 50 µM against MCF-7 (breast) and K-562 (leukemia) cell lines, several-fold poorer than damnacanthal and other substituted anthraquinones — with the plain hydroxymethyl substituent judged a weak pharmacophore 3Reference 3Total synthesis, cytotoxic effects of damnacanthal, nordamnacanthal and related anthraquinone analoguesView study →.
Gap: the two datasets point in opposite directions and both are preclinical isolate work (one dated in-vivo screen, one modern cell panel). No consistent, potent anticancer effect is established, and nothing has been tested in humans 2,
Pau d’arco bark is a recognised antifungal/antibacterial material, but that activity is attributed largely to its naphthoquinones and the whole-extract quinone mix, not to this anthraquinone specifically 5,
Gap: the molecule’s own antifungal contribution is not isolated or quantified — it is a co-constituent in extracts whose activity is carried mainly by other quinones 4,
Mechanisms
| Target / pathway | Effect | Relevant to |
|---|---|---|
| Helicobacter pylori growth | inhibition at low MIC (2 µg/mL); quinone redox/electrophilic mechanism inferred from the class, not resolved for this molecule | antibacterial |
| Tumour-cell viability (P-388; MCF-7/K-562) | cytotoxic in one in-vivo leukemia screen, weak in modern cell panels — no defined molecular target | cytotoxic screening |
| Quinone scaffold (redox cycling / electrophilicity) | the shared basis of anthraquinone/naphthoquinone antimicrobial action; SAR work localises the activity to the quinone core | antimicrobial (class-level) |
No mechanism has been resolved for 2-hydroxymethylanthraquinone specifically; the entries above are inferred from its quinone class 6Reference 6In vitroStructure-activity relationship studies of antimicrobial naphthoquinones derived from constituents of Tabebuia avellanedae — in vitroView study →.
Pharmacokinetics
Not characterised. No absorption, distribution, metabolism, bioavailability or half-life data exist for the isolated compound. As a lipophilic, poorly water-soluble anthraquinone it would be expected to share the general anthraquinone problem of extensive conjugation and limited systemic exposure (as documented for emodin and chrysophanol), which would temper any in-vitro potency — but for this molecule that is an expectation, not a measurement.
Clinical Trials
None. There are no clinical trials of isolated 2-hydroxymethylanthraquinone, and none registered. Human research on pau d’arco uses whole-bark extract standardised to other markers, not this compound.
| Completed | Planned | Terminated | Preclinical |
|---|---|---|---|
| — | — | — | In-vitro anti-H. pylori; cytotoxicity screening; antimicrobial extract work |
Last checked: July 2026.
Isolate vs. Plant Studies
The isolate-vs-plant line matters more than usual here, because the two bodies of evidence barely overlap. The isolated compound has been tested directly in only a few assays — the anti-H. pylori MIC 1Reference 1In vitroAntibacterial activity of Tabebuia impetiginosa Martius ex DC (taheebo) against Helicobacter pylori — in vitroView study → and the cytotoxicity screens 2,
Major Natural Sources
| Source | Botanical | Part | Notes |
|---|---|---|---|
| Pau d’arco (lapacho/taheebo) | Tabebuia impetiginosa (syn. Handroanthus impetiginosus) | Inner bark / heartwood | Minor anthraquinone alongside the dominant naphthoquinones lapachol and beta-lapachone 1, |
| Teak | Tectona grandis | Heartwood / sawdust | Co-occurs with tectoquinone (2-methylanthraquinone) and deoxylapachol in the durable, decay-resistant wood 4Reference 4Identification of anti-wood rot compounds in teak (Tectona grandis L.f.) sawdust extractView study → |
| — | Morinda parvifolia | Root | Isolated among cytotoxic anthraquinones in antileukemic fractionation 2Reference 2Cytotoxic antileukemic anthraquinones from Morinda parvifolia |
Concentrations are not reliably quantified for this molecule in any source — it is consistently reported as a minor constituent, not a headline one. Occurrence data beyond these three sources are sparse; the compound is a recurrent but low-abundance member of the anthraquinone pool in Bignoniaceae, Verbenaceae/Lamiaceae (teak) and Rubiaceae (Morinda).
Prevalence in Nature
2-Hydroxymethylanthraquinone is a minor, widely-scattered plant anthraquinone rather than a signature compound of any one species. It is structurally the hydroxymethyl relative of tectoquinone (2-methylanthraquinone), the anthraquinone that helps make teak heartwood naturally durable and termite-resistant, and the two co-occur in teak wood extractives 4Reference 4Identification of anti-wood rot compounds in teak (Tectona grandis L.f.) sawdust extractView study →. In pau d’arco it sits within the bark’s quinone fraction, overshadowed by the naphthoquinones 1,
Discovery & Synthesis
2-Hydroxymethylanthraquinone is a structurally simple, long-known anthraquinone rather than a compound with a single dramatic discovery story. Its modern appearances in the natural-products literature include isolation from teak heartwood extractives, from Morinda parvifolia roots in antileukemic bioassay work 2Reference 2Cytotoxic antileukemic anthraquinones from Morinda parvifolia, and — the reference point — from pau d’arco inner bark in Park et al.’s 2006 anti-Helicobacter fractionation 1Reference 1In vitroAntibacterial activity of Tabebuia impetiginosa Martius ex DC (taheebo) against Helicobacter pylori — in vitroView study →. It is readily prepared synthetically as well; it features as an analogue in anthraquinone structure-activity studies (e.g. the damnacanthal/nordamnacanthal synthetic series), where it serves as a simple hydroxymethyl-substituted comparator 3Reference 3Total synthesis, cytotoxic effects of damnacanthal, nordamnacanthal and related anthraquinone analoguesView study →. Manufacture, where needed, is by synthesis rather than plant extraction — the natural occurrences are too dilute to be a practical source.
Patents: not yet researched.
Toxicity & Safety
The isolated compound carries a low flag, but this reflects the absence of characterised hazard rather than a clean bill of health — there is essentially no toxicology on the pure molecule. What can be said honestly is structural: it is a simple, non-hydroxylated anthraquinone, so it does not belong to the hydroxyanthracene/anthranoid laxative sub-class (senna, cascara, emodin-type) that carries the genotoxicity signal and EU restriction; those concerns are tied to the ring-hydroxylated anthranoids, not this compound. Anthraquinones as a broad class have raised carcinogenicity questions (the parent 9,10-anthraquinone is flagged by IARC), but no such data exist for 2-hydroxymethylanthraquinone specifically. As always, safety cannot be inferred from silence.
- Not a laxative anthranoid. It lacks the ring hydroxyls of the senna/cascara/emodin purgatives and carries no known laxative or associated genotoxic-anthranoid concern.
- Toxicology essentially uncharacterised. No isolate-specific genotoxicity, repeat-dose, reproductive or carcinogenicity data exist; the “low” rating is provisional and rests on absence of findings, not on clearance.
- Isolate potency is not intake. The in-vitro antibacterial MIC and animal leukemia data do not translate to a safe or effective human exposure; there is no established dose, no pharmacokinetics, and no clinical safety record.
Dosage
There is no established human dose for 2-hydroxymethylanthraquinone. It is not sold or used as a supplement. In research it has appeared only as an isolated test article — at an anti-Helicobacter pylori MIC of 2 µg/mL in vitro 1Reference 1In vitroAntibacterial activity of Tabebuia impetiginosa Martius ex DC (taheebo) against Helicobacter pylori — in vitroView study →, and in an animal antileukemic screen 2Reference 2Cytotoxic antileukemic anthraquinones from Morinda parvifolia. Human exposure, where it occurs at all, is incidental to consuming pau d’arco (taheebo) bark preparations or teak-derived material, in which it is a minor constituent among other quinones; those products are dosed and studied as whole extracts, not for this molecule. These are research conditions, not a personal recommendation.
References
- Park, B. S., Lee, H. K., Lee, S. E., et al. (2006). Antibacterial activity of Tabebuia impetiginosa Martius ex DC (taheebo) against Helicobacter pylori — in vitro. Journal of Ethnopharmacology, 105(1-2), 255-262. https://pubmed.ncbi.nlm.nih.gov/16359837/
- Chang, P., & Lee, K. H. (1984). Cytotoxic antileukemic anthraquinones from Morinda parvifolia. Phytochemistry, 23(8), 1733-1736.
- Akhtar, M. N., Zareen, S., Yeap, S. K., et al. (2013). Total synthesis, cytotoxic effects of damnacanthal, nordamnacanthal and related anthraquinone analogues. Molecules, 18(8), 10042-10055. https://pubmed.ncbi.nlm.nih.gov/23966087/
- Sumthong, P., Romero-González, R. R., & Verpoorte, R. (2008). Identification of anti-wood rot compounds in teak (Tectona grandis L.f.) sawdust extract. Journal of Wood Chemistry and Technology, 28(4), 247-260. https://doi.org/10.1080/02773810802452592
- Zhang, J., Hunto, S. T., Yang, Y., Lee, J., & Cho, J. Y. (2020). Tabebuia impetiginosa: a comprehensive review on traditional uses, phytochemistry, and immunopharmacological properties — review. Molecules, 25(18), 4294. https://pubmed.ncbi.nlm.nih.gov/32962180/
- Yamashita, M., Sawano, J., Umeda, R., Tatsumi, A., Kumeda, Y., & Iida, A. (2021). Structure-activity relationship studies of antimicrobial naphthoquinones derived from constituents of Tabebuia avellanedae — in vitro. Chemical and Pharmaceutical Bulletin, 69(7), 661-673. https://pubmed.ncbi.nlm.nih.gov/34193715/
