Plant Comparison
Pot marigold 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.
At a glance
Pot marigold and Japanese knotweed: they share 4 indicated uses (arthritis / joint pain, cancer (anticancer research), inflammation (general), …); 3 pharmacological actions in common.
Evidence face-off — shared uses
| Condition | Pot marigold | Japanese knotweed | Verdict |
|---|---|---|---|
| Arthritis / joint pain | 5/10 | 2/10 | Stronger for Pot marigold |
| Cancer (anticancer research) | 7/10 | 2/10 | Stronger for Pot marigold |
| Inflammation (general) | 5/10 | 7/10 | Stronger for Japanese knotweed |
| Skin irritation | 5/10 | 1/10 | Stronger for Pot marigold |
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
Principal wound-healing and anti-inflammatory constituents of the flower.
Antioxidant flavonoids and carotenoids give the flower its orange-yellow colour and contribute to its antioxidant activity.
Minor aromatic and resinous constituents of the flower head.
Considered the principal bioactive constituents, responsible for much of the antioxidant, anti-inflammatory and cardioprotective activity attributed to this root.
Emodin has laxative and anti-inflammatory activity at typical concentrations but can cause gastrointestinal upset at high doses.
Pharmacological Actions
Calendula officinalis extracts show cytotoxic antitumor, pro-apoptotic and antimetastatic activity across many cancer cell lines and in animal models (preclinical).
Traditional & Indicated Uses
inferred from anti-inflammatory action
A Calendula officinalis (LACE) aqueous extract inhibits proliferation (70-100%) of leukemia, melanoma, breast, prostate, lung and colon cancer cell lines via G0/G1 arrest and caspase-3 apoptosis and inhibits melanoma growth in nude mice; a systematic review documents its cytotoxic and antimetastatic antitumour activity (preclinical).
inferred from antifungal action
inferred from anti-inflammatory action
inferred from anti-inflammatory action
inferred from anti-inflammatory action
inferred from anticancer action
inferred from anti-inflammatory action
Safety, Cautions & Contraindications
Generally very safe for topical use. May cause contact dermatitis in rare cases (Asteraceae family allergy). Internal use is safe in normal doses. Avoid during pregnancy at therapeutic doses (uterine stimulant potential). Generally safe during breastfeeding for topical use.
Duke (2002) rates calendula (Calendula officinalis) and notes anti-inflammatory, wound-healing (vulnerary), antifungal, and antispasmodic activities at experimental levels. Commission E (KOM) approves calendula flower for wound healing and anti-inflammatory uses, both topically and as a gargle. The plant contains flavonoids, triterpene saponins (oleanolic acid glycosides), and essential oils. Dose: 1–2 g dried flower as tea (for mouth rinse/gargle); or as cream/ointment containing 2–5% calendula extract for topical use. Duke notes that calendula is generally very well-tolerated, though Asteraceae sensitivity can occasionally cause allergic reactions (Duke, 2002).
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.
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
Botanical Description
Aromatic annual or short-lived perennial herb with soft, hairy, oblong leaves and branching, slightly sticky stems. The flower heads are bright orange to yellow, daisy-like, with numerous narrow ray florets surrounding a darker central disc, opening in sunlight and closing at dusk.[1]
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]
Habitat
Widely cultivated as a garden and medicinal plant; believed native to southern Europe and the Mediterranean, now naturalised in gardens and waste ground worldwide.[1]
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 flower heads (or just the ray-floret petals) are picked by hand as they open, through the flowering season, and dried quickly in a warm, shaded, airy place to preserve colour and resin content.[1]
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]
Traditional Uses
Calendula flower is one of the most widely used topical wound-healing and skin-soothing herbs in Western herbal medicine, applied to cuts, grazes, minor burns and skin inflammation, and used internally as a gentle anti-inflammatory and antimicrobial remedy and as a gargle for mouth and throat irritation.[1]
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
Dried petals infused in a carrier oil, used as a soothing base for topical creams and balms for skin healing.
Standardised flower extract formulated into a cream or ointment for topical wound and skin care; the best-studied modern form.
Dried flower infused in hot water, 1-2 g in 150 ml, used still warm as a mouth rinse or gargle 2-4 times daily. The EU herbal monograph's posology for this preparation is OROMUCOSAL only - it does not support taking the infusion internally. Educational reference only, not a prescription.
Dosage
The EU herbal monograph gives semi-solid preparations containing the equivalent of 2-10% herbal substance, applied as a thin layer to the affected area 2 to 4 times daily. Educational reference only, not a prescription.
The EU herbal monograph gives 1-2 g of the flower in 150 mL water as an infusion, used still warm for rinsing and gargling 2 to 4 times daily, or to prepare impregnated dressings for the skin. This is an oromucosal and cutaneous preparation, not an oral tea. Educational reference only, not a prescription.
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
Lookalikes Review
References & Sources
- Givol, O., Kornhaber, R., Visentin, D., Cleary, M. et al (2019) 'A systematic review of Calendula officinalis extract for wound healing', Wound Repair and Regeneration, 27(5), pp. 548-561. doi:10.1111/wrr.12737 Meta-analysis / review
https://doi.org/10.1111/wrr.12737 - Shahane, K., Kshirsagar, M., Tambe, S., Jain, D. et al (2023) 'An Updated Review on the Multifaceted Therapeutic Potential of Calendula officinalis L', Pharmaceuticals (Basel), 16(4), pp. 611. doi:10.3390/ph16040611 Traditional / reference
https://doi.org/10.3390/ph16040611 - Saffari, E., Mohammad-Alizadeh-Charandabi, S., Adibpour, M., Mirghafourvand, M. et al (2016) 'Comparing the effects of Calendula officinalis and clotrimazole on vaginal Candidiasis: A randomized controlled trial', Women & Health, 57(10), pp. 1145-1160. doi:10.1080/03630242.2016.1263272 Randomized trial
https://doi.org/10.1080/03630242.2016.1263272 - Cruceriu, D., Balacescu, O. and Rakosy, E (2018) 'Calendula officinalis: potential roles in cancer treatment and palliative care', Integrative Cancer Therapies, 17(4), pp. 1068-1078. doi:10.1177/1534735418803766 Meta-analysis / review
https://doi.org/10.1177/1534735418803766 - Rezai, S., Rahzani, K., Hekmatpou, D. and Rostami, A (2023) 'Effect of oral Calendula officinalis on second-degree burn wound healing', Scars, Burns & Healing, 9, pp. 20595131221134053. doi:10.1177/20595131221134053 Randomized trial
https://doi.org/10.1177/20595131221134053 - Kadowaki, W., Miyata, R., Mizuno, S., Fujinami, M., Sato, Y. and Kumazawa, S (2023) 'Prenylated acetophenones from the roots of Calendula officinalis and their anti-inflammatory activity', Bioscience, Biotechnology, and Biochemistry, 87(7), pp. 683-687. doi:10.1093/bbb/zbad042 Preclinical
https://doi.org/10.1093/bbb/zbad042 - Samra, R.M., Maatooq, G.T. and Zaki, A.A (2022) 'A new antiprotozoal compound from Calendula officinalis', Natural Product Research, 36(22), pp. 5747-5752. doi:10.1080/14786419.2021.2023868 Preclinical
https://doi.org/10.1080/14786419.2021.2023868 - Kaur, J., Sidhu, S., Chopra, K. and Khan, M.U (2016) 'Calendula officinalis ameliorates l-arginine-induced acute necrotizing pancreatitis in rats', Pharmaceutical Biology, 54(12), pp. 2951-2959. doi:10.1080/13880209.2016.1195848 Preclinical
https://doi.org/10.1080/13880209.2016.1195848 - Aro, A.A., Perez, M.O., Vieira, C.P., Esquisatto, M.A.M., Rodrigues, R.A.F., Gomes, L. and Pimentel, E.R (2014) 'Effect of Calendula officinalis cream on achilles tendon healing', Anatomical Record, 298(2), pp. 428-435. doi:10.1002/ar.23057 Preclinical
https://doi.org/10.1002/ar.23057 - Zhang, X., Wang, R., Finiuk, N., Stoika, R., Lin, H., Wang, X. and Jin, M (2023) 'Active compounds from Calendula officinalis flowers act via PI3K and ERK signaling pathways to offer neuroprotective effects against Parkinson's disease', Food Science & Nutrition, 12(1), pp. 450-458. doi:10.1002/fsn3.3792 Preclinical
https://doi.org/10.1002/fsn3.3792 - Kadowaki, W., Miyata, R., Fujinami, M., Sato, Y. and Kumazawa, S (2023) 'Catechol-O-methyltransferase inhibitors from Calendula officinalis leaf', Molecules, 28(3), pp. 1333. doi:10.3390/molecules28031333 Preclinical
https://doi.org/10.3390/molecules28031333 - European Medicines Agency (HMPC) (2018) 'European Union herbal monograph on Calendula officinalis L., flos, Revision 1'. Available at: https://www.ema.europa.eu/en/documents/herbal-monograph/final-european-union-herbal-monograph-calendula-officinalis-l-flos-revision-1_en.pdf Traditional / reference
https://www.ema.europa.eu/en/documents/herbal-monograph/final-european-union-herbal-monograph-calendula-officinalis-l-flos-revision-1_en.pdf - Hoffmann, D (2003) 'Medical Herbalism'. Traditional / reference
https://scholar.google.com/scholar?q=Medical%20Herbalism - Nicolaus, C. et al (2017) 'A double-blind, randomized controlled trial to investigate the efficacy and safety of a monograph-based Calendula cream versus a comparator cream', 35(1), pp. 81--89. Randomized trial
https://scholar.google.com/scholar?q=A%20double-blind%2C%20randomized%20controlled%20trial%20to%20investigate%20the%20efficacy%20and%20safety%20of%20a%20monograph-based%20Calendula%20cream%20versus%20a%20comparator%20cream - Preethi, K.C. and Kuttan, R (2009) 'Wound healing activity of flower extract of Calendula officinalis', 20(1), pp. 73--79. doi:10.1515/jbcpp.2009.20.1.73 Preclinical
https://doi.org/10.1515/jbcpp.2009.20.1.73 - Jimenez-Medina, E. and Garcia-Lora, A. and Paco, L. and Algarra, I. and Collado, A. and Garrido, F (2006) 'A new extract of the plant Calendula officinalis produces a dual in vitro effect: cytotoxic anti-tumor activity and lymphocyte activation', BMC Cancer, 6, pp. 119. doi:10.1186/1471-2407-6-119 Preclinical
https://doi.org/10.1186/1471-2407-6-119 - 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
- 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - 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 - Royal Botanic Gardens, Kew (n.d.). Available at: https://powo.science.kew.org Traditional / reference
https://powo.science.kew.org - World Health Organization (2007) 'WHO Monographs on Selected Medicinal Plants'. Traditional / reference
https://scholar.google.com/scholar?q=WHO%20Monographs%20on%20Selected%20Medicinal%20Plants - 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.