What to know about Lablab purpureus (hyacinth bean) before using it medicinally

Lablab purpureus, commonly known as hyacinth bean, is a nutrient-rich herb that possesses several health properties, including its ability to lower blood sugar levels and prevent chronic diseases such as cardiovascular and kidney disorders.

The main horticultural aspects of Lablab purpureus involve its growth as a legume crop that thrives in well-drained soils and warm climates, often requiring minimal maintenance to produce high yields of edible beans. From a botanical perspective, Lablab purpureus belongs to the Fabaceae family and is characterized by its distinctive purple flowers and bean pods.

The herb has been a vital part of traditional medicine and cuisine in various cultures, with historical references to its use dating back to ancient India, Africa, and Southeast Asia.

This article explains the medicinal, horticultural, botanical, and historical aspects of Lablab purpureus.

What are the medicinal properties of Lablab purpureus?

Lablab purpureus helps with various health conditions, including diarrhea, dysentery, and fever. It has been used to treat skin conditions like eczema, ringworm, and acne due to its antifungal and antibacterial properties. Its seeds are also used as a treatment for rheumatism and arthritis. Additionally, the plant has been used as a natural remedy for asthma, bronchitis, and other respiratory problems.

The active constituents responsible for the medicinal properties of Lablab purpureus include isoorientin, isovitexin, and calceolarioside A. These compounds have been shown to exhibit antioxidant, anti-inflammatory, and antimicrobial activities, which contribute to the plant's therapeutic effects. Isoorientin, in particular, has been found to have significant antioxidant activity, protecting against oxidative stress and cell damage.

The parts of the plant that are most used for medicinal purposes are its seeds, leaves, and pods. The seeds are rich in protein, fiber, and essential nutrients, making them a popular ingredient in traditional medicine. The leaves and pods are also used for their anti-inflammatory and antimicrobial properties, making them effective in treating various health conditions.

When used improperly, Lablab purpureus can cause side effects such as gastrointestinal upset, allergic reactions, and kidney damage. The seeds, in particular, contain a compound called calceolarioside A, which can cause digestive problems if consumed in excess. Additionally, the plant can interact with certain medications, such as blood thinners and diabetes medications, which can lead to adverse health effects.

When using Lablab purpureus medicinally, it is essential to follow certain precautions. Pregnant and breastfeeding women should avoid consuming the plant, as it can cause uterine contractions and harm the fetus or baby. Individuals with kidney or liver disease should also avoid using the plant, as it can exacerbate these conditions.

What are the horticulural aspects of Lablab purpureus?

Lablab purpureus grow best in tropical and subtropical regions with warm temperatures and high humidity. It thrives in full sun to partial shade and well-drained soil with a pH between 6.0 and 7.0. Adequate moisture is essential, with annual rainfall of at least 1,000 mm.

To plant Lablab purpureus, start with fresh seeds in spring or early summer when soil temperature reaches 20°C. Sow seeds 2-3 cm deep and 10-15 cm apart in rows 1-2 m apart. Alternatively, seedlings can be transplanted to a larger pot or directly into the ground. Planting in blocks rather than rows can promote better air circulation.

Lablab purpureus pods are ready for harvest 60-80 days after sowing. Pick pods regularly to encourage continuous production. Harvest the pods when they are bright red or purple, as this indicates maturity. Leave some pods to dry on the plant to allow seeds to mature.

Common pests of Lablab purpureus include aphids, whiteflies, and spider mites. Fungal diseases such as powdery mildew and leaf spot can also affect the plant. Regular monitoring and maintenance, including pruning and crop rotation, can help prevent the spread of pests and diseases.

What are the botanical aspects of Lablab purpureus?

Lablab purpureus is an annual legume with a climbing habit, growing up to 3-4 meters in length. Its stems are green, hairy, and covered with sharp thorns. Leaves are trifoliate, with three leaflets, and the stipules are modified into sharp spines. Flowers are purple to pink, fragrant, and in clusters.

Lablab purpureus belongs to the family Fabaceae, subfamily Faboideae, and is closely related to the Phaseolus genus. It is a member of the tribe Phaseoleae and is characterized by the presence of a distinctive tricarinate calyx. The species name "purpureus" refers to the purple color of the flowers.

Several variants of Lablab purpureus have been identified, including the 'Ritro' and 'Giant' cultivars. These variants differ in their growth habits, flower colors, and pod sizes. The 'Ritro' cultivar is more compact and has white flowers, while the 'Giant' cultivar produces larger pods and has a more vigorous growth habit.

Lablab purpureus is native to tropical and subtropical regions of Africa, Asia, and Australia. It is widely cultivated in many parts of the world, including the Indian subcontinent, Southeast Asia, and the Pacific Islands. It grows best in warm, humid climates and can tolerate a range of soil types.

The life cycle of Lablab purpureus typically takes around 70-80 days to complete. Germination occurs within 7-10 days of sowing, followed by a rapid growth phase. Flowers appear after about 50 days, and pod formation begins soon after. The pods mature after about 20-30 days, and the seeds are ready for harvest after about 60-70 days.

What are the historical aspects of Lablab purpureus?

Lablab purpureus is a legume that has been used for various purposes in ancient cultures. It was used as a food source, particularly in Asia and Africa, where it was boiled or roasted as a protein-rich legume. In some regions, its beans were used to make a fermented paste.

In Hindu mythology, the lablab tree is associated with the goddess Lakshmi, who is said to have emerged from a lablab flower. The lablab tree is also mentioned in the ancient Hindu text, the Mahabharata, where it is described as a source of food for the gods. The lablab tree is also associated with the Greek goddess Aphrodite.

The lablab bean has been imbued with symbolic meanings across various cultures. In Hinduism, it is associated with the goddess Durga, representing strength and courage. In ancient China, it was associated with wealth and prosperity. In some African cultures, it is a symbol of fertility and abundance.

Lablab purpureus is mentioned in several historical texts, including the ancient Indian medical text, the Charaka Samhita, which describes its use as a treatment for various ailments. It is also mentioned in the ancient Greek text, the De Materia Medica, by Dioscorides, as a treatment for indigestion and diarrhea.

Historical artifacts related to lablab purpureus include ancient pottery and sculptures depicting the plant in various contexts. In ancient China, lablab beans were used as a form of currency, and artifacts from this period often feature the plant in intricate designs. In some African cultures, lablab beans were used in traditional masks and ceremonial objects.