Index

Vietnamese names : Nghể răm, Răm nước, Thủy liễu, Rau nghể, Mã liễu, Phiắc phíe (Tay)

Scientific name :  Polygonum hydropiper  L.

Synonym:  Persica hydropiper  (L.) Spach

Family : Polygonaceae (Vietnamese Coriander)

Uses:  Laxative, snake bites, worms (the whole plant is decocted and drunk or crushed to extract the juice). Also used to treat high blood pressure, stop bleeding, rheumatism, acute enteritis, amoebic dysentery, scabies, and boils.

1. Description

• An annual herbaceous plant, 20–70 cm tall. The stem is erect, highly branched, with long, smooth internodes. Leaves are alternate, narrowly lanceolate, with very short petioles, rounded base, pointed tip, 4–6 cm long, 1–1.3 cm wide, smooth on both sides or with few hairs on the main veins and margins, the upper surface sometimes has V-shaped rough patches; the stipules are thin and hairy.
• The inflorescence grows at the top of the stem and in the leaf axils near the top in long, slender spikes, often curving downwards; bracts are funnel-shaped, hairy at the edges; flowers are red; perianth has 4 glandular lobes (sometimes 3-5); stamens 6, missing.
• The fruit is oval, glossy, sometimes triangular, and has a persistent perianth.
• Fruit season: September-December.

2. Distribution and Ecology

Polygonum L. is a large genus comprising species widely distributed throughout the world. In Vietnam, there are 30 species (Nguyen Tien Ban, 1997), of which nearly 20 are used as medicine (Vo Van Chi, 1996).

The plant known as *Centella asiatica* is widely distributed throughout tropical and subtropical Asia and parts of Europe. In Asia, it has been recorded in India, Sri Lanka, Bangladesh, Malaysia, Thailand, the Philippines, Indonesia, Cambodia, Laos, and China. In Vietnam, it is found in all provinces, from the plains to the midlands and mountainous regions (below 500m). The plant prefers sunlight and particularly moisture, so it often grows in marshy soil in rice paddies, field edges, ponds, streams, and canals. It grows almost year-round, most vigorously during the rainy season, producing abundant flowers and fruits; it branches vigorously from the base.

In Vietnam, purslane is considered a weed that affects crops.

3. Parts used

The entire plant is dried in the sun or in a drying machine.

4. Chemical composition

The entire plant contains substances belonging to many different chemical groups:

• Flavonoids 2 - 2.5% including quercetin, quercitrin, kaempferol, rutin, hyperoside (quercetin - 3 - galactoside), rhamnacin, rhamnacin potassium bisulfate monoester, persicarin (isorhamnetin - 3 - potassium bisulfate ester), persícarin - 7 - methyl - ether).
• According to several authors, the leaves contain many flavonoids: quercetin-3-sulfate, isorhamnetin-3,7-disulfate and tamarixetin-3-glucosid-7-sulfate (Yagi Akữa et al. 1994), 7,4′-dimethylquercetin, 3'-methyl quercetin, quercetin, isoquercitrin (Haraguchi Hừoyulci et al., 1992).
• The antioxidant properties of some flavonoids are ranked in order from strongest to weakest: isoquercitrin > 7,4'-dimethylquercetin > quercetin > 3'-methyl quercetin.
• Essential oil content is 0.30–0.35%, of which one substance accounts for 28.40% (stem), 29.00% (leaf), and another substance accounts for 27.65% (stem) and 27.78% (leaf). Other components present in the stem and leaf essential oils are: humulene (7.06%, 7.14%, respectively), a substance with a molecular weight of 218 (4.62%, 4.51%), a sesquiterpene alcohol (4.86%, 4.89%), and curcumen (2.5%, 2.53%) (Nx Dung et al., 1994).
• Tannins, organic acids (formic acid, acetic acid, valeric acid, malic acid, melissic acid).
• In addition, there is also vitamin K, polygopiperine, alkaloids, sesquiterpenes (polypiperic acid, polygodial 0.08%). (The Wealth of India VIII, 1969; CA 124: 284.344s; CA 122: 51.449y; CA 120: 48.066x).

5. Pharmacological effects

Ether and acid extracts of Polygonum multiflorum have antibacterial effects. Polygonum multiflorum has stimulant, diuretic, astringent, menstrual regulating, and stone-dissolving effects; the activity of the roots is lost when dried.

The plant Polygonum multiflorum has a laxative effect and counteracts the toxicity of cobra venom to a certain extent, improving survival rates or prolonging the duration of venom-injected animals. Polygonum multiflorum root extract, in the form of kerosene, alcohol, and water, administered orally to rabbits at a dose of 100 mg/kg for 3 days, inhibited ovulation induced by copper acetate (4 mg/kg, single intravenous injection) in rabbits at rates of 60%, 20%, and 20%, respectively. Polygonum multiflorum root extract with kerosene, administered orally to female white rats at a dose of 100 mg/kg on days 1-5 after mating, inhibited conception by 100%. Polygonum multiflorum root extract did not have anti-fertility effects in the late stages of pregnancy.

Livestock that eat purslane develop gastrointestinal inflammation and hematuria. Purslane causes contact dermatitis in both humans and livestock. A 5% purslane solution kills 80% of mosquito larvae or 50% of maggots after 3 days. Purslane stimulates uterine contractions.

6. Taste and Function

Fresh perilla leaves have a spicy, aromatic flavor and a warming nature, and are effective in relieving stagnation and killing bacteria.

7. Uses

The stems and leaves of the Polygonum multiflorum plant are used as an anthelmintic, laxative, diuretic, and snakebite remedy. The daily dose is 8-12g of dried plant decoction, or 20-30g of fresh plant crushed, watered, and the liquid drunk. 40-60g of fresh Polygonum multiflorum decoction is used to treat bacillary dysentery, enteritis, and rheumatic swelling and pain. To treat scabies and skin rashes, use fresh Polygonum multiflorum to make a bath and rub the remaining pulp on the affected areas.

In Indian folk medicine, the liquid extract of *Centella asiatica* is used as a contraceptive. A decoction of the plant is used to treat uterine disorders and stop bleeding. The leaves are chewed to treat toothaches. The roots have stimulating, diuretic, carminative, and anthelmintic effects. The dried powder of the plant is sprinkled on clothing to repel moths. In Russia, the people use *Centella asiatica* liquid extract as an astringent, hemostatic, and to treat postpartum hemorrhage.

8. Herbal remedy containing perilla leaves

• To treat rheumatism and itching:  Boil the leaves of *Cynanchum stauntonii*, *Cynanchum auriculatum*, *Cynanchum auriculatum*, and *Cynanchum auriculatum* in water for steaming and bathing.
• Wound treatment:  Crush the leaves of the *Gynura procumbens* plant, add a little water, and apply to the wound.
• Treatment for snake bites:  Take 25 sprigs of *Cynanchum stauntonii*, 25 leaves of *Alum* (a type of black alum), 1 tobacco pipe (a small round pellet the size of a corn kernel), and 15g of *Cynanchum stauntonii* (roots and thorns of the climbing plant). Grind all four ingredients finely, add a bowl of boiled and cooled water, filter the liquid, add a few grains of salt, and divide into 3 doses to drink throughout the day. Apply the remaining pulp to the snake bite wound. Treatment time is approximately 3-4 days.