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Family Polygonacea
Drooping knotweed
Polygonum pubescens Blume
Fumao liao

Scientific names Common names
Persicaria flaccida (Meisn.) Nakai ex Sasaki Drooping knotweed (Engl.)
Persicaria flaccida (Meisn.) H. Gross  
Persicaria pubescens (Blume) H. Hara  
Polygonum doneii Meisn.  
Polygonum flaccidum Hook. f.  
Polygonum hispidum Buch.-Ham. ex D.Don  
Polygonum pubescens Blume  
Polygonum orzetorum Blume  
Polygonum pubescens Blume is an accepted name The Plant List

Other vernacular names
CHINESE: Fu mao liao, Ban jiao cao, Chui liao, La liao cao, Ruan jing shui liao.
JAPANESE: Bontoku tade.
MARATHI: Sisori.

Polygonum pubescens is a perennial herb, much taller than Polygonum hydropiper, up to 75 centimeters tall. Leaves are stalkless, 5 to 15 centimeters long, smooth or hairy. Pinkish-red flowers are borne in drooping racemes, 15 centimeters long, and slender. Nut is small, black, and minutely granular.

- In swampy places at low altitude in Cagayan Province in Luzon.
- Also occurs in India, China, Taiwan and Malaya.

- Plant yields anthocyanin (cyanidin glycoside, peonidin glycoside), flavonol (myricetin 3-0-rhamnoside, quercetin 3-O-(2"-galloylrhamnoside), quercetin 3-O-rhamnoside. (4)
- Study of petroleum ether and ethyl acetate extracts of aerial parts yielded 22 compounds, a new phenylpropanoide ester (1) and 21 known compounds. (5)

- Emmenagogue, abortifacient.


- Leaves used as potherb or seasoning.
- In China the bruised plant is applied locally to blistered and swollen feet.
- Used for snake bites.
- Plant decoction, combined with onion, used as styptic i.e., to stop wound bleeding.
- Also used as emmenagogue and abortifacient.
- In India's Arunachal Pradesh, whole plant paste is thrown into the stream to stupefy the fish, make them float up for an easy catch.

Phytoremediation / Cadmium:
Study evaluated the accumulation characteristics of Cd in Polygonum pubescens. Under all test concentrations, Cd content in the roots and shoots exceeded 100 mg/kg and the enrichment coefficient over 1. Results showed P. pubescens has high tolerance and accumulation capacity of Cd, with a potential on phytoremediation of Cd-contaminated soil. (2)
Phytoremediation / Manganese:
Study evaluated the Mn tolerance and accumulation of Polygonum pubescens under different Mn concentrations. P. pubescens showed certain tolerance to Mn contaminated soil.
• New Phenylpropanoid Ester:
Study of aerial parts yielded 22 compounds, i.e., a new phenylpropa-noide ester and 21 known compounds. Sixteen compounds were evaluated for cytotoxic and anti-inflammatory activities. Some compounds showed effects on different targets. (5)


Updated October 2018 / November 2015

IMAGE SOURCE: File:Persicaria pubescens.JPG/ Show_ryu / 4 Oct 2010 / GNU Free Documentation License / Wikimedia Commons

Additional Sources and Suggested Readings
Traditional knowledge of Adi tribe of Arunachal Pradesh on plants / R C Srivastava and Adi community / Indian Journ of Traditional Knowledge, Vol 8(2), April 2009, pp 146-153
Accumulation characteristics of Cd in Polygonum pubescens Bl. / Deng Hua / Agricultural Science and Technology (Jun. 2010)
Sorting Polygonum names / /Maintained by: Michel H. Porcher / MULTILINGUAL MULTISCRIPT PLANT NAME DATABASE / Copyright © 1995 - 2020 / A Work in Progress. School of Agriculture and Food Systems. Faculty of Land & Food Resources. The University of Melbourne. Australia.
Flavonoid Properties of five Families newly Incorporated into the Order Caryophyllales (Review) / Tsukasa Iwashina / Bull. Natl. Mus. Nat. Sci., Ser. B, 39(1), pp. 25–51, February 22, 2013
A new sucrosephenylpropanoid ester from Polygonum pubescens Blume / Qiang Liu, Bin Li, Jianping Zhao, Shabana I Khan, Wen-bin Lu, Ting Zeng et al / Natural Product Research, 2017; 31(15) /

It is not uncommon for links on studies/sources to change. Copying and pasting the information on the search window or using the DOI (if available) will often redirect to the new link page.

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