Forest-poppy
StarHylomecon japonica
Synonyms: Stylophorum japonicum, Chelidonium japonicum
Traditionally used for
- Digestion
- Pain & joints
Cautions & contraindications
- Toxic — professional use only
Western Herbalism Properties
Traditional Uses
In Chinese folk medicine and traditional practice the forest poppy (known as hua quan cao) is used: the whole plant is prepared as a remedy for stomach and abdominal pain and for rheumatic joint and muscle pain. The plant contains toxic isoquinoline alkaloids and is regarded as poisonous, so it is used with caution. No North American indigenous use is documented.
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Botanical Description
Hylomecon japonica, the forest poppy or wood poppy, is a delicate rhizomatous perennial herb in the poppy family (Papaveraceae), native to the temperate woodlands of eastern Asia including Japan, Korea, northeastern China and the Russian Far East, where it grows in moist, shaded deciduous forest, on humus-rich slopes and along stream banks. It arises from a slender, branching rhizome and reaches 15 to 30 centimetres tall, with soft, sparsely hairy stems that exude a yellow to orange latex when broken. The mostly basal, long-stalked leaves are pinnately divided into several ovate, sharply and irregularly toothed leaflets. In spring it bears solitary or few, bright golden-yellow, four-petalled flowers about 3 to 4 centimetres across on slender stalks, the petals broad and slightly overlapping around a central cluster of numerous stamens. The fruit is a narrow, cylindrical capsule that splits to release the seeds. The plant is grown as a shade-garden ornamental and, like other poppy relatives, contains alkaloid-rich latex.
Active Constituents
6-Methoxydihydrosanguinarine
Benzophenanthridine isoquinoline alkaloidConcentration: Principal benzophenanthridine of the root and rhizome; isolated from 80 percent ethanol and from methanol extracts
The most-studied single compound of this drug. It inhibits MCF-7 breast carcinoma cells with an IC50 below 20 microM, and in MCF-7 it accumulates reactive oxygen species and suppresses PI3K/AKT/mTOR signalling, inducing both apoptosis and autophagy. It also blocks Candida albicans filamentation and biofilm formation by downregulating the cAMP pathway genes EFG1, CDC35, RAS1 and TPK2.
Protopine
Protopine-type isoquinoline alkaloidConcentration: Reported as the most abundant alkaloid recovered by acid-base total alkaloid extraction of the root
Antibacterial against Gram-positive organisms in TLC-bioautography screening of the root alkaloids. Protopine is roughly ten to twenty times less cytotoxic than the quaternary benzophenanthridines that accompany it, so it is not the drug's dose-limiting toxin.
Sanguinarine
Quaternary benzophenanthridine alkaloidConcentration: Root; a minor constituent relative to its dihydro and 6-substituted derivatives
A broadly cytotoxic quaternary alkaloid and, with chelerythrine and coptisine, one of the constituents identified by LC-MS/MS intracellular-accumulation screening as responsible for the hepatocellular toxicity of the related Papaveraceae drug Chelidonium majus. Its presence is the main reason this root should not be treated as a bland folk remedy.
Chelerythrine
Quaternary benzophenanthridine alkaloidConcentration: Root; present alongside a large family of 6-substituted dihydrochelerythrine derivatives
A protein kinase C inhibitor that causes growth arrest or death in most mammalian cell lines, and one of the alkaloids implicated in Chelidonium majus liver injury. It also inhibits mitochondrial NADH and succinate dehydrogenase in the same experimental systems.
Dihydrosanguinarine
Dihydrobenzophenanthridine isoquinoline alkaloidConcentration: Root
One of the antibacterial alkaloids of the root, active mainly against Gram-positive bacteria. It is also one of the two components proposed to carry the anti-inflammatory activity of Hylomecon methanol extracts through downregulation of ERK1/2 and p38 phosphorylation.
Allocryptopine
Protopine-type isoquinoline alkaloidConcentration: Root and rhizome; isolated together with cryptopine and protopine
A minor alkaloid shared with Chelidonium majus and Macleaya cordata. In Chelidonium studies it contributes to inhibition of hepatic mitochondrial respiration, so it is best read as part of the drug's cumulative alkaloid burden rather than as a therapeutic principle.
Hylomeconoside A
Oleanane-type triterpenoid saponinConcentration: Whole herb; one of more than twenty hylomeconoside saponins reported from this species
Moderately cytotoxic to MGC-803 gastric carcinoma and HL-60 promyelocytic leukaemia cells in the 30 to 45 microgram per millilitre range. Saponins of this series are glycosides of gypsogenin and quillaic acid, the same aglycones that carry the adjuvant and haemolytic activity of Quillaja saponins.
Hylomeconoside J
Oleanane-type triterpenoid saponinConcentration: Whole herb
The most potent of the screened monomer saponins against AGS gastric adenocarcinoma cells, with an IC50 of 6.01 microM, inducing apoptosis dose-dependently. Most of the other hylomeconosides were inactive over 10 to 100 microM, so activity in this series is structure-specific rather than a general saponin effect.
⚠ Drug Interactions
Chelidonium majus (Bai Qu Cai)
Both drugs are Papaveraceae roots carrying the same quaternary benzophenanthridine alkaloids, sanguinarine and chelerythrine, plus protopine and allocryptopine. Sanguinarine, chelerythrine and coptisine are the constituents identified as the hepatotoxic components of Chelidonium majus, and Chelidonium is the subject of causality-assessed spontaneous reports of herb-induced liver injury. The East Asian article is often supplied as Chelidonium asiaticum, which is a variety of Chelidonium majus and carries the same alkaloids. No hepatotoxicity study has been published on Hylomecon japonica itself, so the concern is inferred from shared chemistry rather than measured in this species.
Clinical note: Do not combine the two in one formula, and do not use either as a substitute for the other without recalculating the total alkaloid dose. Check baseline liver enzymes and repeat them if use runs beyond a few weeks.
Macleaya cordata (Bo Luo Hui)
Macleaya cordata is the commercial source of sanguinarine and chelerythrine and is a recognised toxic drug used almost entirely externally. Hylomecon japonica carries the same two alkaloids. Co-administration stacks the same quaternary benzophenanthridine exposure from two directions without any pharmacological rationale for doing so.
Clinical note: Avoid the combination. If Bo Luo Hui is being applied topically over broken skin, treat that as systemic exposure when a Hylomecon-containing internal formula is also in use.
Hepatotoxic drugs such as methotrexate, isoniazid and azole antifungals
Extrapolated from the alkaloid class, not measured for this herb. The benzophenanthridines and protopine alkaloids present here inhibit hepatic mitochondrial NADH and succinate dehydrogenase in vitro, and the same alkaloids account for the hepatotoxicity of Chelidonium majus. There are no pharmacokinetic, hepatic-safety or drug-metabolism data for Hylomecon japonica in humans at all.
Clinical note: Treat concurrent use with a known hepatotoxin as a reason to monitor transaminases, and stop the herb first if they rise.
Coreanomecon hylomeconoides, formerly Hylomecon hylomeconoides
This is a sourcing hazard rather than a pharmacological interaction. Two of the most-cited pharmacology papers attached to Hylomecon japonica in review articles actually used Hylomecon hylomeconoides, a Korean endemic now placed in the segregate genus Coreanomecon: the 2010 anti-MRSA study and the 2012 RAW 264.7 anti-inflammatory study. The 2004 report that 6-methoxydihydrosanguinarine kills HT29 colon carcinoma cells likewise isolated the compound from that species. The compound itself is genuinely present in Hylomecon japonica, but the extract-level activity claims are not this species' data.
Clinical note: When citing antibacterial or anti-inflammatory evidence for this herb, check which Hylomecon was actually assayed. Do not accept a supplier's antimicrobial claim that traces back to the Korean species.
Dosage Calculator
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Evidence Tier
Moderate evidence · 6 studiesRecorded studies by study design, strongest design at the top. This is a study-design tier only, not a GRADE rating: it does not weigh risk of bias, consistency or precision.
Systematic review / meta-analysis
0
Randomized controlled trial
0
Other clinical trial
0
Observational / case report
0
In vitro / animal
6
1 verified · 5 unverified
Show 6 studies
- Isoquinoline alkaloids from Hylomecon japonica and their potential anti-breast cancer activities
- 6-Methoxydihydrosanguinarine induces apoptosis and autophagy in breast cancer MCF-7 cells by accumulating ROS to suppress the PI3K/AKT/mTOR signaling pathway
- TLC Bioautography-guided Isolation and Antimicrobial, Antifungal Effects of 12 Alkaloids from Hylomecon japonica Roots
- Bioactive oleanane-type saponins from Hylomecon Japonica
- Discovery of novel adjuvants: Identification of saponins from Hylomecon japonica (Thunb.) Prantl & Kündig and insights into their in vitro and in vivo activities.
- Effects of Hylomecon vernalis ethanol extracts on cell cycle and apoptosis of colon cancer cells
Other / unclassified
0
Verified: design read from PubMed for a DOI that resolves to the cited paper Unverified: taken from the study's recorded description
Clinical Studies
Isoquinoline alkaloids from Hylomecon japonica and their potential anti-breast cancer activities
Twenty-six isoquinoline alkaloids, nine of them previously undescribed, were isolated from the roots and rhizomes and tested against MCF-7 breast cancer cells. Eight, including 6-methoxydihydrosanguinarine and several 6-substituted dihydrochelerythrines, inhibited MCF-7 with IC50 below 20 microM. This is a cell-line screen with no normal-cell comparator reported in the abstract, so it establishes chemistry and cytotoxicity, not therapeutic selectivity.
6-Methoxydihydrosanguinarine induces apoptosis and autophagy in breast cancer MCF-7 cells by accumulating ROS to suppress the PI3K/AKT/mTOR signaling pathway
Network pharmacology plus cell work in MCF-7. The alkaloid raised reactive oxygen species, inhibited PI3K/AKT/mTOR signalling and induced both apoptosis and autophagy; N-acetylcysteine reversed the effects and the PI3K inhibitor LY294002 amplified them. Entirely in vitro, in one cell line, with no animal or human component.
TLC Bioautography-guided Isolation and Antimicrobial, Antifungal Effects of 12 Alkaloids from Hylomecon japonica Roots
Bioautography-guided isolation from the roots of this species, so the taxonomy is sound. Twelve alkaloids were assayed against Staphylococcus aureus, Candida albicans, Pseudomonas aeruginosa and Escherichia coli. Activity ranked benzophenanthridine isoquinoline alkaloids above steroid alkaloids above protoberberine alkaloids, with the strongest effects against Gram-positive organisms. Broth and plate work only.
Bioactive oleanane-type saponins from Hylomecon Japonica
Six undescribed oleanane saponins, hylomeconosides L to Q, from the whole herb, characterised as gypsogenin and quillaic acid glycosides. They showed selective cytotoxicity across A549, AGS, HeLa, Huh7, HT29 and K562 lines. Useful for identifying the saponin aglycones, which are the same ones that make Quillaja saponins haemolytic; it says nothing about oral efficacy.
Discovery of novel adjuvants: Identification of saponins from Hylomecon japonica (Thunb.) Prantl & Kündig and insights into their in vitro and in vivo activities.
Fourteen triterpenoid saponins were isolated from the herb and screened for immune-adjuvant activity. One new saponin promoted proliferation and phagocytosis in spleen lymphocytes, DC2.4 and RAW 264.7 cells, and in immunised mice raised specific serum antibody, Th1 and Th2 cytokines and dendritic cell maturation via TLR4/MyD88/NF-kB. A mouse adjuvant study, not a therapeutic trial, and the relevance to an oral decoction of the crude root is unestablished.
Effects of Hylomecon vernalis ethanol extracts on cell cycle and apoptosis of colon cancer cells
Published under the synonym Hylomecon vernalis. An ethanol extract that was 89.67 percent alkaloid by HPLC-MS inhibited HT-29 and SW620 colon cancer cells with IC50 of 0.105 and 0.146 milligrams per millilitre, arrested cells in G1 and shifted caspase-3, caspase-9 and Bcl-2 expression. Cell culture only. The very high alkaloid fraction is also a reminder of how concentrated an ethanol extract of this root is compared with a water decoction.
Historical Texts
Medicinal Plant Flora of Tianmu Mountain in Zhejiang Province (Zhejiang Tianmushan Yaoyongzhiwuzhi)
1965, Health Bureau of Zhejiang ProvinceHerbal Medicines of Shaanxi (Shaanxi Zhongcaoyao)
1971, Science Press, Beijing, pages 500 to 501National Compilation of Chinese Herbal Medicines (Quanguo Zhongcaoyao Huibian)
1975, People's Medical Publishing HouseA Record of Medicinal Herbs on Mount Hua (Huashan Yaowuzhi)
1985, Shaanxi Science and Technology Publishing House, page 277Chinese Materia Medica (Zhonghua Bencao)
1999, Shanghai Scientific and Technical Publishers, pages 2269 to 2270References
- Tian Y, Xia G, Zhu J, Li L, Zang H. Hylomecon japonica: A Review About Botanical Aspects, Traditional Applications, Chemical Composition, and Pharmacological Properties . Horticulturae (2025) [DOI]
- Wang M, Shi P, Zhang M, Han N. Chemical Constituents and Biological Activities of the Hylomecon japonica (Thunb.) Prantl & Kündig – A Comprehensive Review . Chemistry & Biodiversity (2024) [DOI]
- Itokawa H, Ikuta A, Tsutsui N, Ishiguro I. Alkaloids and a sterol from Chelidonium japonicum . Phytochemistry (1978) [DOI]
- Li X, Sun Y, Wang M, Wang Z, Kuang H. Alkaloids in Chelidonium majus L: a review of its phytochemistry, pharmacology and toxicology . Frontiers in Pharmacology (2024) [DOI]
- Wu C, Wang X, Xu M, Liu Y, Di X. Intracellular Accumulation as an Indicator of Cytotoxicity to Screen Hepatotoxic Components of Chelidonium majus L. by LC-MS/MS . Molecules (2019) [DOI]
- Zhang M, Yang J, Sun Y, Kuang H. Recent Advances in Alkaloids from Papaveraceae in China: Structural Characteristics and Pharmacological Effects . Molecules (2024) [DOI]
This information is for educational purposes only and is not intended to replace professional medical advice. Always consult a qualified healthcare provider before using any herbal remedy, especially if you are pregnant, nursing, or taking medications.
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