Gaajar Ghaas ( Parthenium hysterophorus)
This plant is also known as chatak chaandani in Hindi and carrot grass/santa maria feverfew in English. It belongs to family Asteraceae. Native to Mexico, Caribbean, Central and South America, this weed is believed to have been introduced into India as contaminants in PL 480 wheat imported from the USA in the 1950s (as Public Law 480 passed in 1954 to give food grains to developing countries for eliminating starvation and malnutrition). Pre-sently, this invasive weed is widely prevalent in India.
Plant description: P. hysterophorus is an erect, much-branched with vigorous growth habit, aromatic, annual or a short-lived perennial, herbaceous plant with a deep taproot. The species reproduces by seed. It grows to 30-90 cm but up to 1.5 m, or even 2.5 m, in exotic situations. It has pale green deeply lobed leaves, 8-20 cm in length and 4-8 cm in width. Both leaves and stems are covered with short, soft trichomes. Flower heads are both terminal and axillary, pedunculate and slightly hairy, being composed of many florets formed into small white capitula, 3-5 mm in diameter. Seeds (achenes) are black, flattened, about 2 mm long, each with two thin, straw-coloured appendages at the apex.
Chemical composition: Parthenin, hymenin, coronopilin, dihydroisoparthenin, hysterin, hysterophorin and tetraneurin are some of the chemical compounds found in this plant. The main dangerously toxic substance found in this plant is parthenin.
Health hazards to humans and livestock: Parthenium weed is a poisonous or lethal weed to those who are sensitive to it. It may cause allergenic eczematous contact dermatitis, rhinitis, bronchial asthma, itching and fever in humans.
Prevention and control: This plant reproduces by large numbers of seeds, 10-25,000 per mature plant. These seeds are dispersed by wind, water, animals, vehicles, tools and machinery and on clothing so the prevention of spread is difficult. Seed production should be prevented by destroying the plants before flowering or seed setting and this is the best method to control P. hysterophorus.The seed can also stay for years in the soil seed bank and the continuous removal of the weed is required until the seed bank is depleted.
Uses: Studies are going on to use this plant as a remedy for skin inflammation, rheumatic pain, diarrhoea, urinary tract infections, dysentery, malaria and neuralgia.
Dr. Pratibha Mamgain, Dept.of Ayurvedic Medicine
