Polygonum barbatum L

[From Greek, polus = many and gonos = angled, and from Latin, barbatus = bearded]

Physical description: It is a perennial aquatic herb which grows to a height of 90 cm. It is found by the stream-side, in wet areas, besides water and in the swamps of China, Taiwan, Bhutan, India, Myanmar, Nepal, the Philippines, Indonesia and Malaysia, from sea level to 1300 m. The stems grow from a rhizome, are reddish, pubescent, bitter and

Synonymy: Pericardia barbata (Linnaeus) H. Hara; Pericardia omerostroma (Ohki) Sasaki; Polygonum kotoshoense K. Ohki; Polygonum omerostromum Ohki.

Common names: Knotweed; tebok seludang (Malay); mao liao (Chinese).

sweet-sour-tasting. Leaves: simple, alternate and stipulate. The ochrea is tubular, 1.5cm-2cm long, membranous, and densely hispidulous. The petiole is 5 mm-8 mm long and densely hispidulous. The blade is lanceolate or elliptic-lanceolate, 7cm-15cm x 1.5cm-4cm, and pubescent. The base of the blade is cuneate, the margin is ciliate, and the apex is acuminate. The inflorescences are terminal, spicate, erect, 4cm-8cm, and comprise of several spikes aggregated like panicles. The flowers are small and comprise of a white or greenish perianth made of 5 elliptic 1.5mm-2mm long lobes. The andrecium consists of 5-8 pinkish stamens. The gynecium comprises of 3 styles and a few capitate stigmas. The fruits are black, ovoid, trigonous, 1.5 mm-2 mm long shiny achenes included in the perianth (Fig. 77).

Pharmaceutical interest:

Fig. 77. Polygonum barbatum L.

Anti-inflammatory properties: An aqueous extract of Polygonum punctatum given orally at 300,mg/Kg-600 mg/Kg to rats inhibits carrageenan-induced oedema (Simoes CM et a/, 1989). This activity might be mediated by tannins or even resveratrol, characterized later from Po/ygonum sp., which inhibit experimentally the enzymatic activity of rat polymorphonuclear leukocytes lipo-oxygenase and cyclo-oxygenase (Kimura Y et a/., 1985). Inhibitors of lipo-oxygenase and cyclo-oxygenase, key enzymes of the inflammatory process, are useful for treating inflammation. A classical example of cyclo-oxygenase inhibitor is aspirine, the forerunner of which is a natural product: salicin.

Uses: In Malaysia, the plant is used to invigorate health after childbirth and to expel intestinal worms. In Cambodia, Laos and Vietnam, the seeds of Po/ygonum barbatum L. are astringent and used to treat cholera, stop dysentery and to invigorate health.

Antiviral and antibacterial properties: An aqueous extract of Polygonum punctatum hampers the proliferation of Herpes Simplex Virus type-1 cultured in vitro (Kott V et al., 1999). It would be interesting to find out the principles involved here. An aqueous extract of Polygonum capitatum decreases the death rate of mice

Resveratrol

Resveratrol

Stigmast - 4 - ene - 3, 6 dione Stigmastane - 3, 6 - dione

Fig. 78. Note the similitude of chemical structures of stigmast-4-ene-3, 6-dione, stigmastane-3, 6-dione, hecogenin and betamethasone.

Hecogenin Betamethasone

Fig. 78. Note the similitude of chemical structures of stigmast-4-ene-3, 6-dione, stigmastane-3, 6-dione, hecogenin and betamethasone.

experimentally infected with Escherichia coli, and the body temperature of infected rabbits (Ren G et al., 1995).

Continue reading here: Polygonum chinense L

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