Billy Goat Weed

Overview

The species is native to tropical Central and South America and is now found naturalized pan-tropically in disturbed areas as weeds. It is common in the warm tropics throughout Africa, Asia, and the South Pacific Island. Although it is harmful to crops and invades cultivated fields and interferes with the natural community compositions, it has been used as folk medicine in several countries and it has anti-microbial, insecticidal and nematicidal properties.

Vernacular Names

Billy Goat Weed/Goatweed (English), Babandotan (Indonesia), Ara batu (Malay), Yaa saap haeng (Thai), Pagpagai (Philippines), Nia kee lo (Laos), Uchunti (Bengali, India), Chuva (Spanish), Agerate (French).

Agroecology

It occurs in the warm tropics from sea level to 2,500 m alt, in wet and dry disturbed areas. It is usually found in waste places, gardens, old cultivations, grassIands, forest edges, road sides, etc., where there is ample exposure to sunlight. It thrives best in rich, moist, mineral soils in areas with high air humidity and tolerate shades.

Morphology

• Roots - fibrous. It has a shallow tap root system.
• Stems - erect, pubescent, aromatic, slender, branching 15-100 cm high annually, covered with fine white hairs.
• Leaves - simple, petiolate, green, ovate or rhomboidovate, 1-10 cm x 0.5-7 cm, with crenate margin, acute apex, attenuate base, glandular dorsally. Leaves are opposite, pubescent with long petioles and include glandular trichomes.
• Flowers - inflorescense terminal corymb of 8-15 discoid heads, florets about 75 per head; corolla tubular, white or pale purple or blue, 1-1.5 mm long, limb 5-cleft, and are self-incompatible.
• Fruits - an achene with an aristate pappus and is easily dispersed by wind and animals fir.
• Seeds - are positively photoblastic and remain viable upto 12 months. The seeds germinate between 20-25°C. It prefers a moist, well drained soil but may tolerate dry conditions.

Cultivation

• Generative propagation is done by seeds.
• Utilizing open planting area to plant non-intrusive intercropped plants.
• Propagation by stem cuttings is more efficient than by seed or root, resulting in rapid growth and reproduction. Protoplasts have been isolated from leaves, stems and callus has regenarated.

Chemical Constituents

Leaves and flowers: saponins, flavonoids and polyphenol. Leaves: amino acid, essential oils, coumarin, ageratochromene, friedelin, ß-sitosterol, stigmasterol, tannins. Roots: essential oils, alkaloids and coumarin.

Traditional Medicinal Uses

• The whole plant is antiinflammatory, antiallergic, antinematocidal, anticoagulant, smooth muscle relaxant, haemostatic, analgesic, antifungal, antibacterial and hypothermic activities have been recorded. The plant also has an antidiarrhoeal effect.
• As a stimulant, tonic, fever reliever (antipyretic), anti-toxic, eliminate swelling, menstrual laxative (emenagogue), urinary laxative (diuretic), and laxative fart (carminative). potency of antijuvenil hormone from plants. Saponins is toxic to organisms poikilothermic because it can hemolyze red blood cells.
• It is widely used externally to treat skin diseases, wounds, ulcers and boils; haemorrhages, and internally as febrifuge.
• In Malaysia, leaves are used externally to heal wounds, cuts, scratches, itches and to alleviate tooth-ache; a decoction of the root is taken for treating coughs and a decoction of the whole plant is taken against asthma.
• In Philippines, the juice of fresh leaves is widely used as vulnerary, and leaves cooked in coconut oil are also applied to wounds. A decoction of the herb is used to treat stomach troubles.
• In Papua New Guinea, a solution of crushed leaves is taken to treat diarrhoea and juice from squeezed leaves is used to treat sore eyes.
• In New Britain, the leaves are used against fever and dysentery and externally to heal wounds.
• In Thailand, the leaves are used for treating wounds, itching and eye inflammations.
• In South China A. conyzoides is traditionally used as green manure in fields to increase the crop yields, and usually is intercropped as understory in citrus orchards to suppress weeds and control other pests.