Vernonia amygdalina, of the Astaraceae family, is a medicinal herb commonly known as bitter leaf. This plant is indigenous to tropical Africa, has significant medicinal uses, and is regarded as a gold mine by many African communities.
The plant is normally found along rivers and lakes, in forest margins, woodland, and open grass land – either in the wild or cultivated. It grows very well under conditions of strong sun exposure and humidity. The Vernonia amygdalina plant is a shrub that grows to a height of 1-3m, with petiole leafs of about 6mm in diameter and about 20cm in length, elliptical in shape. The leaves are dark green, with a characteristic odour, and have a bitter taste. The bark is grey or brown and has a rough texture that is flaked. Its flowers are small, white, and clustered with small fruits that are slightly hairy, with small nuts inside. Although the bitter leaf plant has been harvested in the wild for centuries, some communities have taken the initiative to grow it on farms. This is because herbal clinics are emerging which use it widely as an ingredient in the herbal formulations, and also because of its demand as a vegetable in some communities.
This bitter leaf plant is propagated by seeds and stem cuttings. Communities or traditional healers collect the seeds from dry flower heads and first plant them in nursery beds, to produce seedlings that can then be transplanted 4-6 weeks after their emergence. Nevertheless, stem cuttings are also used in the propagation of bitter leaf plants, because they can grow faster. The cuttings are planted upright or slanted at an angle, to obtain more side shoots. Harvesting the plant happens during the rainy season, as this allows the new leafy shoots to grow for another harvest, a few weeks later. In the dry season, only the leaves of the plant are harvested without cutting the shoot, since there is not enough water for the plant to regrow.
Bitter leaf has been used as food and medicine for centuries in Africa. There is a wide spectrum of uses for the plant in African traditional medicine, and it has been used to manage and treat a number of health conditions. For instance, traditional healers across the African continent use the plant for medical conditions including fever, malaria, stomach ache, skin infections like ringworm, acne, diabetes, cancer, insomnia, hepatitis, toothache, jaundice, diarrhea, bilharzias, pneumonia, tuberculosis, stroke, arthritis, wounds, fatigue, and cough. It is also used as an anti-parasitic, anti-bacterial, anti-inflammatory and anti-helminthes, as a laxative, an appetiser, an aphrodisiac, and for weight loss.
The plant parts are prepared in different ways to treat different ailments. For example, the roots of the plant are pounded and boiled with water to make a decoction for treatment of stomach and gastrointestinal problems, while the decoction from the leaves is used to treat malaria, fever, and cough. A traditional healer can prescribe a prepared decoction dose for patients based on the type and extent of the sickness.
In some communities, the stems of the bitter leaf are used as chew-sticks for oral hygiene, and for the management of some dental problems. The sap from the leaves can also be squeezed out and mixed with a small quantity of water, and drunk twice daily to treat stomach upsets.
Bitter leaf has also been used for gynaecological purposes by traditional birth attendants (TBAs). TBAs are elderly women in rural villages who help expectant mothers to deliver children in their homes. They prepare a leaf decoction which causes the expulsion of the placenta after birth, aid post-partum uterine contraction, induce lactation, and control post-partum haemorrhage. The leaf decoction is recommended by traditional healers and TBAs to be taken regularly by breastfeeding mothers, to increase milk quality and production.
Some small- and medium-scale industries use bitter leaf in their herbal soap formulations – and for brewing beer which is drunk to restore stamina.
In some African communities, the leaves of the plant form part of the local diet. The leaves are prepared by being boiled, but the water is changed at intervals until all the traces of bitterness are washed off; then the less bitter boiled leaves are added to a sauce and spiced according to taste.
Nutritionally, bitter leaf is one of the leafy vegetables which have been used to alleviate the effects of malnutrition, as it is exceptionally rich in proteins, vitamins, and mineral elements including iron, phosphorus, calcium, potassium, zinc, copper, folic acids, and ascorbic acid.
Scientific studies show that Vernonia amygdalina is rich in bioactive compounds such as alkaloids, saponins, terpenes, flavanoids, and phenolic acids, which have various medicinal properties including preventing cancer and treating microbial infections. Some of these bio-active compounds contribute to the bitter taste of this miracle plant.
The diverse medicinal and nutritional uses of Vernonia amygdalina ensure this important plant is kept close to the hearts of African communities.