Plant Comparison

Elecampane vs Japanese knotweed

A side-by-side comparison of two medicinal plants — every documented constituent, action, use, safety note and cited source, assembled automatically from the Omnia Sana database.

First plant
Second plant
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Plant AElecampaneInula heleniumAsteraceaeFull monograph →
Plant BJapanese knotweedReynoutria japonicaPolygonaceaeFull monograph →

At a glance

Elecampane and Japanese knotweed: they share 4 indicated uses (arthritis / joint pain, cancer (anticancer research), inflammation (general), …); 2 pharmacological actions in common.

ElecampaneJapanese knotweed
Constituents34
Pharmacological actions43
Indicated uses95
Safety notes22
Cited sources1414
Indicated uses
Only Elecampane
BronchitisCoughInfection (general)Respiratory supportWounds
Shared (4)
Arthritis / joint painCancer (anticancer research)Inflammation (general)Skin irritation
Only Japanese knotweed
Cardiovascular / heart health
Pharmacological actions
Only Elecampane
AntimicrobialExpectorant
Shared (2)
Anti-inflammatoryAnticancer (preclinical)
Only Japanese knotweed
Antioxidant

Evidence face-off — shared uses

ConditionElecampaneJapanese knotweedVerdict
Arthritis / joint pain2/102/10Comparable evidence
Cancer (anticancer research)2/102/10Comparable evidence
Inflammation (general)2/107/10Stronger for Japanese knotweed
Skin irritation2/101/10Comparable evidence

Evidence scores (1–10) are computed from the tier of each cited source. “Comparable” means the two scores are within one point. Follow a score to its detailed sources.

Key Constituents

Sesquiterpene lactones (alantolactone, isoalantolactone, igalan, diplophyllin)[2, 12, 13, 14]

The antimicrobial and anti-inflammatory principles of the root; the eudesmane core and the alpha,beta-methylene-lactone ring are essential for the antimicrobial activity.

Sesquiterpene lactonesSesquiterpenes
Inulin[12]

A fructan polysaccharide abundant in the root (the genus Inula gives inulin its name).

PolysaccharidesInulin
Essential oil[12]

Aromatic constituents of the root.

Essential (volatile) oil
Stilbenes (resveratrol, piceid)[1, 6]

Considered the principal bioactive constituents, responsible for much of the antioxidant, anti-inflammatory and cardioprotective activity attributed to this root.

Anthraquinones (emodin, physcion)[1]

Emodin has laxative and anti-inflammatory activity at typical concentrations but can cause gastrointestinal upset at high doses.

Anthraquinones
Polysaccharides[5]

Studied for immunomodulatory and other bioactivities.

Polysaccharides
Phenolic glycosides[8]

Minor phenolic constituents of the rhizome.

GlycosidesPhenolic compounds

Pharmacological Actions

Anti-inflammatory[1, 2, 3, 4, 5]

Anti-inflammatory - sesquiterpene lactones (alantolactone, isoalantolactone) inhibit NF-kB and MAPK signalling and pro-inflammatory cytokines; total sesquiterpene lactones eased arthritis in animal models (potential in rheumatoid arthritis)

Anticancer (preclinical)[9, 10, 11]
Antimicrobial[6, 12, 13, 14]

Antimicrobial, notably anti-staphylococcal (membrane-damaging) and anti-mycobacterial (active against Mycobacterium tuberculosis in vitro); supports respiratory and skin infection

Expectorant[1, 12]

Expectorant for productive cough and bronchitis (long-standing respiratory remedy)

Anti-inflammatory[1, 2, 3, 5, 6, 9, 11, 12, 13]
Anticancer (preclinical)[1, 3, 6, 7, 11, 12, 13]
Antioxidant[1, 3, 5, 6, 11, 12, 13]

Traditional & Indicated Uses

Arthritis / joint pain[2]Traditional · 2/10

Anti-inflammatory - sesquiterpene lactones (alantolactone, isoalantolactone) inhibit NF-kB and MAPK signalling and pro-inflammatory cytokines; total sesquiterpene lactones eased arthritis in animal models (potential in rheumatoid arthritis)

Evidence: 2
Label: Arthritis / joint pain
Bronchitis[12]Traditional · 1/10

Expectorant for productive cough and bronchitis (long-standing respiratory remedy)

Evidence: 1
Label: Bronchitis
Cancer (anticancer research)[9, 10, 11]Traditional · 2/10

inferred from anticancer action

Evidence: 2
Label: Cancer (anticancer research)
Cough[12]Traditional · 1/10

Expectorant for productive cough and bronchitis (long-standing respiratory remedy); Soothes irritated airways / chronic catarrh (traditional)

Evidence: 1
Label: Cough
Infection (general)[12, 13, 14]Traditional · 2/10

Antimicrobial, notably anti-staphylococcal (membrane-damaging) and anti-mycobacterial (active against Mycobacterium tuberculosis in vitro); supports respiratory and skin infection

Evidence: 2
Label: Infection (general)
Inflammation (general)[2]Traditional · 2/10

inferred from anti-inflammatory action

Evidence: 2
Label: Inflammation (general)
Respiratory support[12]Traditional · 1/10

inferred from expectorant action

Evidence: 1
Label: Respiratory support
Skin irritation[2]Traditional · 2/10

inferred from anti-inflammatory action

Evidence: 2
Label: Skin irritation
Wounds[12, 13, 14]Traditional · 2/10

inferred from antimicrobial action

Evidence: 2
Label: Wounds
Arthritis / joint pain[9, 11, 12, 13]Traditional · 2/10

inferred from anti-inflammatory action

Evidence: 2
Label: Arthritis / joint pain
Cancer (anticancer research)[7]Traditional · 2/10

inferred from anticancer action

Evidence: 2
Label: Cancer (anticancer research)
Cardiovascular / heart health[6, 11, 12, 13]Traditional · 1/10
Evidence: 1
Label: Cardiovascular / heart health
Inflammation (general)[2, 11, 12, 13]Good · 7/10

inferred from anti-inflammatory action

Evidence: 7
Label: Inflammation (general)
Skin irritation[11, 12, 13]Traditional · 1/10

inferred from anti-inflammatory action

Evidence: 1
Label: Skin irritation

Safety, Cautions & Contraindications

Safety note[12]Info

The sesquiterpene lactones (especially alantolactone) are known skin sensitisers and can cause allergic contact dermatitis; people sensitive to the daisy family (Asteraceae) should be cautious.

Safety note[12]Caution

Large doses can cause nausea, vomiting and diarrhoea; safety in pregnancy and breastfeeding is not established, so avoid medicinal doses.

Safety note[11, 12, 13]Caution

Japanese knotweed root contains resveratrol and emodin; high doses of emodin may cause GI discomfort and have laxative effects. Not recommended during pregnancy (emodin has potential teratogenic effects in animal studies). May interact with anticoagulants and antiplatelet medications. Quality control of commercial preparations is important as invasive weed extracts vary significantly.

Safety note[11, 12, 13, 14]Info

Duke (2002) rates Japanese knotweed (listed as Hu-Zhang, Fallopia japonica) as +++ and highlights its rich content of resveratrol and emodin. Experimental evidence (score 1) supports COX-2 inhibitory, antioxidant, anti-inflammatory, hepatoprotective, and lipid-lowering activities — largely attributed to resveratrol. Duke notes its use in traditional Chinese medicine for fractures, burns, abscesses, and gynecological conditions. No significant clinical trials were available at time of publication, but resveratrol's biological activity is well-documented in vitro (Duke, 2002).

External Ids

Gbif: 3148340
Wikidata: Q697416
Gbif: 2889173
Wikidata: Q18421053

Botanical Description

Tall, robust perennial herb with large, coarse, hairy leaves - broadly oval near the base and progressively smaller up the stem - arising from a thick, aromatic rhizome. Large, shaggy, bright yellow daisy-like flower heads with numerous narrow ray florets are borne at the top of stout, branching stems.[12]

Height: 1-2.5 m
Habit: Tall, robust, coarse-leaved perennial herb
Leaves: Large, coarse, hairy, broadly oval near the base, smaller up the stem
Flowers: Large, shaggy, bright yellow daisy-like heads with numerous narrow ray florets
Stem: Stout, branching, hairy
Root: Thick, aromatic, branching rhizome (the medicinal part)
Fruit: Small achene with a pappus
Flowering Period: July-August

Vigorous, invasive rhizomatous perennial (Polygonaceae) with hollow, bamboo-like, jointed stems 1-3 m tall (occasionally taller), speckled reddish-purple. Leaves are broad, heart- to shovel-shaped with a flat base. Abundant sprays of small, creamy-white flowers appear in late summer, followed by small winged fruit.[6]

Height: 1-3 m (occasionally to 4 m+)
Habit: Vigorous, invasive, rhizomatous perennial
Leaves: Broad, heart- to shovel-shaped, flat-based
Flowers: Small, creamy-white, in abundant sprays
Stem: Hollow, bamboo-like, jointed, reddish-purple speckled
Root: Extensive, deep, aggressively spreading rhizome
Fruit: Small winged achenes
Flowering Period: August-October

Habitat

Grows in damp meadows, pastures, roadsides and woodland margins on moist, rich soils; native to Europe and Western Asia and naturalised in North America.[12]

Native to East Asia (Japan, China, Korea), now a notorious invasive species across Europe and North America, growing in disturbed ground, riverbanks, roadsides and waste land, spreading aggressively via an extensive rhizome network.[6]

Harvesting

The root and rhizome are dug in autumn of the second or later year, when sesquiterpene lactone and inulin content is highest, then cleaned, sliced and dried.[12]

Parts: Root and rhizome
Season: Autumn, from second-year or older plants

The rhizome/root, the main medicinal part, is dug in autumn or winter when resveratrol content is highest; young spring shoots (stems) are also edible and used. Strict containment is required when harvesting, given the plant's severe invasiveness.[6]

Parts: Root, Stem
Season: Root in autumn/winter; young stems in spring

Traditional Uses

Elecampane root has a long European tradition, reflected in the old name 'elf dock', as a warming expectorant remedy for productive cough, bronchitis and chronic respiratory catarrh, and topically and internally as an antimicrobial for skin and wound infections.[12]

Known as Hu Zhang in Traditional Chinese Medicine, Japanese knotweed root has a centuries-old use for inflammation, infections, jaundice and menstrual complaints. Modern interest centres on its resveratrol and emodin content, now studied (as Polygonum cuspidatum extract) for antioxidant, anti-inflammatory, cardioprotective and hepatoprotective activity, and more recently for supportive use in acute respiratory infections.[2, 3, 6]

Preparations

Decoction[12]

Dried root simmered in water as a traditional expectorant and antimicrobial tea.

Decoction[6]

Dried rhizome simmered in water, the classic Traditional Chinese Medicine preparation.

Standardised resveratrol extract (capsule)[1]

The modern commercial supplement form, standardised for resveratrol content.

References

REF-1858, REF-0538, REF-1859, REF-1860, REF-1861, REF-1862, REF-1863, REF-1864, REF-1865, REF-1866, REF-1867
REF-0979, REF-0980, REF-0981, REF-0982, REF-0983, REF-0984, REF-0985, REF-0986, REF-0987, REF-0988

Lookalikes Review

Outcome: none-known
Reviewed By: Omnia Sana (owner-authorized)
Reviewed Date: 2026-07-07
Outcome: none-known
Reviewed By: Omnia Sana (owner-authorized)
Reviewed Date: 2026-07-07

Dosage

Not documented

Standardised extract[11, 12, 13]

Duke (2002) and general phytotherapy guidance treat this as an experimentally supported herb without a single agreed clinical dose; commercial resveratrol-standardised extracts should be dosed per product labelling. Educational reference only, not a prescription; avoid in pregnancy.

References & Sources

  1. Gierlikowska, B., Gierlikowski, W., Bekier, K., Skalicka-Wozniak, K., Czerwinska, M.E. and Kiss, A.K (2019) 'Inula helenium and Grindelia squarrosa as a source of compounds with anti-inflammatory activity in human neutrophils and cultured human respiratory epithelium', Journal of Ethnopharmacology, 249, pp. 112311. doi:10.1016/j.jep.2019.112311 Preclinical
    https://doi.org/10.1016/j.jep.2019.112311
  2. Gao, S. and Wang, Q. and Tian, X.H. and Li, H.L. and Shen, Y.H. and Xu, X.K. and Wu, G.Z. and Hu, Z.L. and Zhang, W.D (2016) 'Total sesquiterpene lactones prepared from Inula helenium L. has potentials in prevention and therapy of rheumatoid arthritis', Journal of Ethnopharmacology, pp. 39--46. doi:10.1016/j.jep.2016.12.020 Preclinical
    https://doi.org/10.1016/j.jep.2016.12.020
  3. Wang, Q., Gao, S., Wu, G., Yang, N., Zu, X., Li, W., Xie, N., Zhang, R., Li, C., Hu, Z. and Zhang, W (2018) 'Total sesquiterpene lactones isolated from Inula helenium L. attenuates 2,4-dinitrochlorobenzene-induced atopic dermatitis-like skin lesions in mice', Phytomedicine, 46, pp. 78-84. doi:10.1016/j.phymed.2018.04.036 Preclinical
    https://doi.org/10.1016/j.phymed.2018.04.036
  4. Dao, T.T.P., Song, K., Kim, J.Y. and Kim, Y.S (2020) 'Igalan from Inula helenium (L.) suppresses the atopic dermatitis-like response in stimulated HaCaT keratinocytes via JAK/STAT3 signaling', Inflammation Research, 69(3), pp. 309-319. doi:10.1007/s00011-020-01322-4 Preclinical
    https://doi.org/10.1007/s00011-020-01322-4
  5. He, X., Zhao, W., Shao, B., Zhang, B., Liu, T., Sun, C., Huang, H., Wu, J., Liang, J. and Ma, X (2020) 'Natural soluble epoxide hydrolase inhibitors from Inula helenium and their interactions with soluble epoxide hydrolase', International Journal of Biological Macromolecules, 161, pp. 1465-1474. doi:10.1016/j.ijbiomac.2020.04.227 Preclinical
    https://doi.org/10.1016/j.ijbiomac.2020.04.227
  6. Buza, V., Niculae, M., Hanganu, D., Pall, E., Burtescu, R.F., Olah, N., Matei-Latiu, M., Vlasiuc, I., Iozon, I., Szakacs, A.R., Ielciu, I. and Stefanut, L.C (2022) 'Biological Activities and Chemical Profile of Gentiana asclepiadea and Inula helenium Ethanolic Extracts', Molecules, 27(11), pp. 3560. doi:10.3390/molecules27113560 Preclinical
    https://doi.org/10.3390/molecules27113560
  7. Zheng, X., Wu, Z., Xu, J., Zhang, X., Tu, Y., Lei, J., Yuan, R., Cheng, H., Wang, Q. and Yu, J (2021) 'Bioactive sesquiterpenes from Inula helenium', Bioorganic Chemistry, 114, pp. 105066. doi:10.1016/j.bioorg.2021.105066 Preclinical
    https://doi.org/10.1016/j.bioorg.2021.105066
  8. Nder, A.E (2021) 'Efficacy of methanol-water extract of Inula helenium root against oxidative DNA damage', Journal of Traditional Chinese Medicine, 41(2), pp. 293-300. Preclinical
    https://scholar.google.com/scholar?q=Efficacy%20of%20methanol-water%20extract%20of%20Inula%20helenium%20root%20against%20oxidative%20DNA%20damage
  9. Chun, J., Song, K. and Kim, Y.S (2018) 'Sesquiterpene lactones-enriched fraction of Inula helenium L. induces apoptosis through inhibition of signal transducers and activators of transcription 3 signaling pathway in MDA-MB-231 breast cancer cells', Phytotherapy Research, 32(12), pp. 2501-2509. doi:10.1002/ptr.6189 Preclinical
    https://doi.org/10.1002/ptr.6189
  10. Li, Y., Ni, Z., Zhu, M., Dong, M., Wang, S., Shi, Q., Zhang, M., Wang, Y., Huo, C., Kiyota, H. and Cong, B (2012) 'Antitumour activities of sesquiterpene lactones from Inula helenium and Inula japonica', Zeitschrift fur Naturforschung C, 67(7-8), pp. 375-380. doi:10.1515/znc-2012-7-804 Preclinical
    https://doi.org/10.1515/znc-2012-7-804
  11. Yan, Y.Y., Zhang, Q., Zhang, B., Yang, B. and Lin, N.M (2019) 'Active ingredients of Inula helenium L. exhibits similar anti-cancer effects as isoalantolactone in pancreatic cancer cells', Natural Product Research, 34(17), pp. 2539-2544. doi:10.1080/14786419.2018.1543676 Preclinical
    https://doi.org/10.1080/14786419.2018.1543676
  12. Kenny, C.R., Stojakowska, A., Furey, A. and Lucey, B (2022) 'From Monographs to Chromatograms: The Antimicrobial Potential of Inula helenium L. (Elecampane) Naturalised in Ireland', Molecules. doi:10.3390/molecules27041406 Traditional / reference
    https://doi.org/10.3390/molecules27041406
  13. Stojanovic-Radic, Z. and Comic, Lj. and Radulovic, N. and Blagojevic, P. and Denic, M. and Miltojevic, A. and Rajkovic, J. and Mihajilov-Krstev, T (2012) 'Antistaphylococcal activity of Inula helenium L. root essential oil: eudesmane sesquiterpene lactones induce cell membrane damage', European Journal of Clinical Microbiology & Infectious Diseases, 31(6), pp. 1015--1025. doi:10.1007/s10096-011-1400-1 Preclinical
    https://doi.org/10.1007/s10096-011-1400-1
  14. Cantrell, C.L. and Abate, L. and Fronczek, F.R. and Franzblau, S.G. and Quijano, L. and Fischer, N.H (1999) 'Antimycobacterial eudesmanolides from Inula helenium and Rudbeckia subtomentosa', Planta Medica, 65(4), pp. 351--355. doi:10.1055/s-1999-14001 Preclinical
    https://doi.org/10.1055/s-1999-14001
  1. Dong, X., Fu, J., Yin, X., Cao, S. and others (2016) 'Emodin: A Review of its Pharmacology, Toxicity and Pharmacokinetics', Phytotherapy Research, 30(8), pp. 1207-1218. doi:10.1002/ptr.5631 Traditional / reference
    https://doi.org/10.1002/ptr.5631
  2. Wang, S., Yang, Y., Sun, L., Qiao, G. and others (2022) 'Reynoutria japonica Houtt for Acute Respiratory Tract Infections in Adults and Children: A Systematic Review', Frontiers in Pharmacology, 13, pp. 787032. doi:10.3389/fphar.2022.787032 Meta-analysis / review
    https://doi.org/10.3389/fphar.2022.787032
  3. Ke, Y., Zhan, L., Lu, T., Zhou, C. and others (2023) 'Advances for pharmacological activities of Polygonum cuspidatum (Reynoutria japonica) - A review', Pharmaceutical Biology, 61(1), pp. 177-188. doi:10.1080/13880209.2022.2158349 Traditional / reference
    https://doi.org/10.1080/13880209.2022.2158349
  4. Zhang, Q., Zhao, Y., Zhang, M., Zhang, Y. and others (2021) 'Bioactive amides from Reynoutria japonica', Journal of Asian Natural Products Research, 23(3), pp. 228-234. doi:10.1080/10286020.2021.1873298 Preclinical
    https://doi.org/10.1080/10286020.2021.1873298
  5. Lai, Y., Zhou, C., Huang, P., Dong, Z. and others (2024) 'Polygonum cuspidatum polysaccharide: A review of its extraction and purification, structure analysis, and biological activity', Journal of Ethnopharmacology, 331, pp. 118079. doi:10.1016/j.jep.2024.118079 Traditional / reference
    https://doi.org/10.1016/j.jep.2024.118079
  6. Peng, W., Qin, R., Li, X. and Zhou, H (2013) 'Botany, phytochemistry, pharmacology, and potential application of Polygonum cuspidatum Sieb. et Zucc.: a review', Journal of Ethnopharmacology, 148(3), pp. 729-745. doi:10.1016/j.jep.2013.05.007 Traditional / reference
    https://doi.org/10.1016/j.jep.2013.05.007
  7. Wang, X., Liang, L., Yan, J., Li, Z. and others (2023) 'Citri Reticulatae Pericarpium-Reynoutria japonica Houtt. herb pair suppresses breast cancer liver metastasis by targeting ECM1-mediated cholesterol biosynthesis pathway', Phytomedicine, 116, pp. 154896. doi:10.1016/j.phymed.2023.154896 Preclinical
    https://doi.org/10.1016/j.phymed.2023.154896
  8. Jiang, Y., Liu, Y., Zhang, X. and others (2020) 'New phenolic glycosides from Reynoutria japonica', Journal of Asian Natural Products Research, 22(1), pp. 17-23. doi:10.1080/10286020.2019.1646730 Preclinical
    https://doi.org/10.1080/10286020.2019.1646730
  9. Liu, Y., Wang, J., Li, Q. and others (2024) 'The Possibility of Polygonum cuspidatum against Osteoarthritis based on Network Pharmacology', Current Computer-Aided Drug Design, 20(2), pp. 121-133. doi:10.2174/1573409919666230403114131 Preclinical
    https://doi.org/10.2174/1573409919666230403114131
  10. Espinosa-Andrews, H., Morales-Hernandez, N., Garcia-Marquez, E. and others (2025) 'Physicochemical and rheological characteristics of commercial Greek-style yogurt enriched with Polygonum cuspidatum roots or the P. cuspidatum beta-cyclodextrin inclusion complex', Food Research International, 203, pp. 115854. doi:10.1016/j.foodres.2025.115854 Preclinical
    https://doi.org/10.1016/j.foodres.2025.115854
  11. Burns, J., Yokota, T., Ashihara, H., Lean, M.E.J. and Crozier, A (2002) 'Plant foods and herbal sources of resveratrol', 50(11), pp. 3337--3340. doi:10.1021/jf0112973 Traditional / reference
    https://doi.org/10.1021/jf0112973
  12. Royal Botanic Gardens, Kew (n.d.). Available at: https://powo.science.kew.org Traditional / reference
    https://powo.science.kew.org
  13. World Health Organization (2007) 'WHO Monographs on Selected Medicinal Plants'. Traditional / reference
    https://scholar.google.com/scholar?q=WHO%20Monographs%20on%20Selected%20Medicinal%20Plants
  14. Duke, J.A (2002) 'Handbook of Medicinal Herbs, Second Edition'. Traditional / reference
    https://scholar.google.com/scholar?q=Handbook%20of%20Medicinal%20Herbs%2C%20Second%20Edition

Generated automatically from the Omnia Sana plant database and its cited sources. For educational purposes only — not medical advice. Always consult a qualified practitioner before using medicinal plants.