Waterleaf

Overview

Waterleaf is probably native to Tropical & Subtropical America. Its complete native range, however, is difficult to ascertain because it is easily transported and easily naturalised. It has become a weed with pantropical distribution, still extending its range. It was introduced into Java in 1915 from Surinam by the Bogor Botanic Gardens. Fresh leaves and stems are eaten raw or added to omeletts, or sandwiches.

Vernacular Names

Grasse grand pourpier (French), Blatt-ginseng (German), Som kaoli (Thai), Beldrogea grande (Portuguese), Espinaca de filipinas (Spanish), Surinaamsche postelein (Dutch).

Agroecology

Waterleaf grows best in the moist humid conditions of lowland tropical areas, though it can succeed at elevations up to 1,000 m. It grows best in areas where the mean annual temperature is within the range of 22-30 °C, though it can tolerate 15-36 °C. It prefers a mean annual rainfall in the range 1,000-2,000 mm, tolerating 500-3,000 mm. Light shade can improve leaf production. Prefers a well-drained but moist, humus-rich fertile soil, though it will succeed in relatively poor soils. Prefers a pH in the range of 5-6.5 but can tolerate 4.5-7.

Morphology

• Roots - a lot of lateral roots.
• Stems - strongly branched, perennial plant with succulent stems.
• Leaves - arranged spirally to nearly opposite, often crowded at the top of the stem and indistinctly or shortly petioled. The leaf-blades are usually spoon-shaped, with a size of measure about 3-15 cm x 1-6 cm, entire and succulent, obtuse to rounded and occasionally notched at the apex.
• Flower - bisexual, 0.5-2.5 cm in diameter; pedicels elongate after anthesis, sepals 2, free, green, persistent; petals 5, obovate, up to 10 mm × 4 mm, pink; stamens 20-40, style 2-3-fid, ovary superior.
• Fruits - capsular, ellipsoid to globular, 4-7 mm long, 2-3-valved and elastically dehiscent, yellow.
• Seeds - numerous, compressed globosereniform, 0.8-1.2 mm long, granulate, glabrous, shining black.
   

Cultivation

• Propagated by seeds - the small seeds are usually mixed with a fine sand before sowing.
• Propagated by cuttings of young shoots 15-20 cm long root readily.

Chemical Constituents

Waterleaf has a rich content of crude protein, total lipids, essential oils, cardiacglycosides, flavonoids and polyphenols. Preliminary phytochemical studies on this plant revealed the presence of omega-3-fatty acids and high levels of essential nutrients like minerals (such as calcium, potassium and magnesium), soluble fibres (such as pectin) and vitamins (such as C, α and β tocopherols and β-carotene) which are required for growth and development. In addition, this plant contains tannins, flavonoids, saponins, quinones, sterols, cyanogenic, glycoside, polyphenol, terpenoids, coumarin, kaempferol, luteolin.

Traditional Medicinal Uses

• Studies have suggested antimicrobial, antioxidant, antidiabetic, antihyperlipidemic, antidiarrheal, neuropharmacological properties.
• Mayan people applied crushed leaves on sores, inflammation, and swelling.
• Root decoction is used as a tonic.
• In South America, the crushing plant is applied as a poultice on contusions and tumours.
• Decoctions are used for painful eyes and to aid recovery from blows and falls.