Marshpepper knotweed – proven benefits, uses


The scientific name of the marshpepper knotweed is Persicaria hydropiper (L.) Delarbre.

Scientific names Common names
Persicaria hydropiper (L.) Delarbre Agagat (Bon.)
Persicaria hydropiper (L.) Opiz Buding (Ig.)
Persicaria hydropiper (L.) Spach Tuba (Bon.)
Persicaria vernalis Nakai Annual smartweed (Engl.)
Polygonum hydropiper Linn. Knotweed (Engl.)
Polygonum schinzii J. Schust. Marshpepper knotweed (Engl.)
Pepperwort (Engl.)
Red smartweed (Engl.)
Water pepper smartweed (Engl.)


Other vernacular names
ARABIC: Fulful El Mâ´, Zangabîl El Kilâb.
BENGALI: Biskatali, Pakarmul, Pakurmul, Panimarich.
BULGARIAN: Piperiče, Piperiche.
CHINESE: Shui liao, La liao cao, Liao, Hung la-liao.
DANISH: Bidende Pileurt.
DUTCH: Bitterplant, Bittertong, Duizendknoop, Waterpeper.
ESTONIAN: Mõru Kirburohi, Mõru Kirburohi.
FINNISH: Akantatar, Katkeratatar.
FRENCH: Curage, Piment D´eau, Poivre D´eau, Poivre D’eau, Renouée Poivre-D´eau, Renouée.
GERMAN: Pfeffer-Knöterich, Wasserpfeffer, Wasserpfeffer-Knöterich.
GREEK: Neropiperia.
HUNGARIAN: Borsos Keserűfű, Vízibors.
INDONESIAN: Si Tuba Sawah.
ITALIAN: Erba Pepe, Pepe D´asino, Pepe Del Povero, Poligono Acre, Poligono Pepe D´acqua, Poligono Pepe D’acqua, Poligono Piperino
JAPANESE: Asabu-tade, Azebu-tade, Benitade, Ta de, Yanagi tade.
KOREAN: Gaeyeoggwi, Kaeyogwi, Yeo-Ggwi, Yeo-Ggwi-Gwa, Yeoggwi, Yeoggwigwa, Yogwi,
MALAY: Daun kesum, Daun Senahun, Rumput Tuboh, Senahun, Tube Seluwang.
NORWEGIAN: Vaspeppar, Vasspepar.
PORTUGUESE: Erva-De-Bicho, Erva-Pessegueira, Persicária, Pimenta De Agua.
RUSSIAN: Gorec Perečnyj, Goretc Perichnyi, Gorets Perechnyj, Perec Vodânoj, Perets Vodyanoj, Vodjanoj Perec, Vodyanoii Peretc.
SPANISH: Pimienta Acuática, Pimienta Acuática, Pimienta De Agua
SWEDISH: Bitterblad, Bitterknäa, Bitterpilört, Bitterpilört, Jungfrutvål, Vattenpeppar, Vattensåpa.
THAI: Phak Phai Nam, Phakchi Mi.

Pepperwort is a smooth, rather robust annual, with tufted or shortly creeping roots. Stems are erect, while the branches are ascending, rather stout and leafy, 30 to 45 centimeters high, often glandular. Nodes are often swollen. Leaves are lanceolate or oblong-lanceolate, up to 7.5 centimeters long. Racemes are flexuous, leafy at the base, threadlike, decurved and interrupted. Flowers are pinkish. Nuts are usually three-sided.


– Found in open wet places, along streams, in old rice paddies, etc., at altitudes of 1,200 to 2000 meters.

– Occurs in warmer parts of the world.


– Seed contains polygonic acid and tannin.

– Leaves contain an essential oil, malic acid and phytosterine.

– Rootstock yield an essential oil, oxymethyl-anthraquinone.

– Screening of ethanol extract yielded alkaloids, flavonoids, saponins, tannins, terpenoids, and steroids. (see study)

– Leaves yield 7.5% protein, 1.9% fat, 8% carbohydrate, 2% ash. Also contains rutin.

– Study of whole plant yielded one new drimane-type sesquiterpenoid, 3 β-angeloyloxy-7-epifutronolide (1), and one new natural product, polygonumate (2), along with six known drimane-type sesquiterpenes– [dendocarbin L, (+) winterin, (+) fuegin, changweikangic acid A, futronolide, and 7-ketoisodrimenin. (see study)

– Various extracts and fractions yielded flavonoids such as (+)-catechin, (−)-epicatechin, hyperin, and isoquercitrin; isorhamnetin, kaempferol, quercetin, quercitrin, rhamnazin and rutin; drimane-typed sesquiterpenes, such as 3-β-angeloyloxy-7-epifutronolide, 7-ketoisodrimenin, changweikangic acid A, dendocarbin L, (+)-fuegin, futronolide, polygonumate, and (+)-winterin; phenylpropanoid esters, including hydropiperosides A and B, and vanicosides A, B and E; and phenolic acids, such as caffeic acid, chlorogenic acid and ρ-coumaric acid. (see study)

knotweedMedicinal properties of pepperwort

– Considered anti-inflammatory, astringent, carminative, contraceptive, diaphoretic, diuretic, emmenagogue, stimulant, stomachic, styptic.

– Juice considered diuretic, carminative and anthelmintic.

– Root is bitter, tonic, and stimulating.

– Studies have suggested antioxidant, antibacterial, antifungal, anthelmintic, cytotoxic, anti-inflammatory, antinociceptive, antifertility and neuroprotective properties.

Parts used

– All plant parts.


– Leaves and stems are edible, raw or cooked.

– Seeds made into a peppery condiment as substitute for pepper.

– Young seeds used as salad garnish.

Folkloric traditional medicine remedies, benefits and  uses of pepperwort

– In China, juice is used for itches; also as diuretic, carminative and anthelmintic.

– Root used as tonic and stimulant.

– Decoction of whole plant used for diarrhea, dyspepsia, hemorrhoids, and excessive menstrual bleeding.

– Bruised leaves used as poultice and cure for toothache.

– Used to regulate menstrual irregularities.

– Among Russian peasant, used as hemostatic.

– Used in all cases of intestinal hemorrhage (pulmonary, gastric, hemorrhoidal, uterine) and used as sedative.

– In the United States, once used as an emmenagogue.

– In Assam, women used the roots for fertility control: Dried root powder used for termination of pregnancy; continuous use for more than a year reported to cause permanent sterility. (see study)

– In Bangladesh, leaf juice used for menstrual pain and leaf paste to stop bleeding. (see study)

– In Vietnam, stems and leaves used for snake bites; also as diuretic and anthelmintic. (see study)

– In Bangladesh, leaves used to treat rheumatic pain, gout, skin diseases (scabies, ringworm), abscesses, snake, dog, and insect bites. (see study)

– In Malaysia, decoction consumed to heal stomach ache; also used to treat dandruff. (see study)

Other uses

– Plant utilized for natural dyes. (see study)

Scientific proven health benefits and uses of pepperwort 

Hydropiperoside / Antifertility Activity:

Study of methanol extract yielded a novel coumaryl glycoside, hydropiperoside, with other known compounds and an unidentified lactone possessing antifertility activity.

Antioxidant Flavonoids:

Study isolated ten flavonoid compounds from the dried leaves of P. hydropiper. The isolated flavonoids were shown to possess strong antioxidative capabilities. The most powerful was galloyl quercitrin.

Study showed good antioxidant activity on ORAC assay.

Antibacterial / Antifungal:

Study of root extract showed significant antibacterial activities against four gram-positive (B subtilis, B megaterium, S aureus and E aerogenes) and four gram-negative (E coli, P aeruginosa, S typhi and S sonnei) bacteria, with antifungal activity against A fumigatus, A niger, A flavus, C albicans, Rizopus oryzae and T rubrum.

Lens Aldose Reductase Inhibition:

Sulfated flavonoids in Polygonum hydropiper showed potent inhibition against lens aldose reductase. Among the flavonoids, the most potent was isorhamnetin 3,7-disulfate.


Study of the methanolic extract of root showed anti-fertility activity in female albino rats. The estrous cycle of the extract treated rats became irregular resulting in failure of gestation. Results suggest the root of PH contains steroidal / estrogenic compounds which affect female reproduction in rats.


Study of 5 kinds of Polygonum hydropiper organic solvent extracts showed the ethyl ether extract to have the strongest insecticidal effect. The insecticidal substance was identified as eugenol. Eugenol showed to have stomach toxicity and contact action; it suppressed AchE and GST activity.

Tyrosinase Activity Inhibitor:

Study isolated taxifolin, a tyrosinase inhibitor from the sprout of Polygonum hydropiper. Compared to cosmetic agents arbutin and kojic acid, taxifolin’s tyrosinase inhibitory effect was equal to the latter, more than the former.

Cytotoxic Activity:

Study showed cytotoxic activity, yielding cytotoxic compounds soluble in both water and ethanol. Results suggest a therapeutic potential in antitumor therapy.

Estradiol-like Effects:

In a study of crude extract of roots , P. hydropiper mimics the effect of estradiol-17ß in the uterine protein profiles of adult female albino rats.

Anti-Inflammatory Effects:

Study of methanol extract of Polygonum hydropiper showed strong anti-inflammatory activity. There was dose-dependent suppression of release of nitric oxide (NO), tumor necrosis factor (TNF)-a, and prostaglandin (PGE2) IN RAW264.7 cells and peritoneal macrophages stimulated by lipopolysaccharide.

Phytoremediation / Nitrogen and Phosphorus:

Study showed the mining ecotype (ME) of P. hydropiper removed as high as 87.47% of total nitrogen and 97.63% of total phosphorus. Results show a theoretical basis for use of P. hydropiper for N and P removal from livestock wastewater and presents as a promising species for the phytoremediation of eutrophic waters.

Antinociceptive / Leaves:

Study evaluated the antinociceptive activity of methanol extract of leaves in both heat- and chemical induced pain models in mice. Results showed significant antinociceptive activity with both central and peripheral mechanisms. Pretreatment with naloxone significantly reversed the antinociceptive produced by the MEPH suggesting involvement of the opioid system.

Antimicrobial / Insecticidal:

Crude extracts of P. persicaria showed significant activity against E. coli. A leaf extract showed significant activity against A. niger and moderate activity against A. flavus, H. maydis, and A. solani. It showed insecticidal activity against T. castaneum, S. oryzae, R. dominica and C. analis.

Anthelmintic / Antiproliferative / Aerial Parts:

Study evaluated aerial parts of Persicaria hydropiper for anthelmintic and antiproliferative activity. Results showed in vitro anthelmintic activity against Pheretima posthuma. Study also showed in vivo antiproliferative activity against Ehrlich Ascites Carcinoma with significant (P>0.05) decrease in tumor weight, increase life span, and reduced tumor cell growth.



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