What to know about Cajanus cajan (pigeon pea) before using it medicinally

Cajanus cajan, commonly known as pigeon pea, is a versatile herb that has been used for centuries to improve overall health and well-being due to its rich content of antioxidants, flavonoids, and phenolic acids.

In the realm of horticulture, this legume is valued for its ease of cultivation, drought tolerance, and adaptability to various soil types, making it a staple crop in many tropical and subtropical regions. Botanically, Cajanus cajan is a member of the Fabaceae family and is characterized by its compound leaves and showy white or pink flowers, which attract a variety of pollinators.

Historically, this herb has been mentioned in ancient Ayurvedic texts and traditional medicine practices, particularly in India and Southeast Asia, where it is revered for its medicinal and culinary properties.

This article explains the medicinal, horticultural, botanical, and historical aspects of Cajanus cajan.

What are the medicinal properties of Cajanus cajan?

Cajanus cajan helps with the treatment of various health conditions such as fever, rheumatism, and skin disorders. Its leaves are also used to treat indigestion and diarrhea. It is also used as a diuretic to treat urinary problems.

The medicinal properties of Cajanus cajan are attributed to its active constituents, including flavonoids, terpenoids, and glycosides. These compounds have been shown to possess anti-inflammatory, antibacterial, and antioxidant properties. Research has also isolated specific compounds such as isorhapontigenin, which has demonstrated antioxidant activity.

The parts of the plant most used for medicinal purposes are the leaves, stems, and seeds. The leaves are used to treat fever and indigestion, while the seeds are used as a diuretic and to treat urinary problems. The stems are used to treat skin disorders and rheumatism.

Improper use of Cajanus cajan can lead to side effects such as allergic reactions, diarrhea, and stomach cramps. Prolonged use can also cause kidney damage and interact with other medications. The plant's seeds can also cause photoxicity, leading to skin irritation upon exposure to sunlight.

Precautions when using Cajanus cajan medicinally include proper identification of the plant and its parts, as well as adherence to recommended dosages. Pregnant and breastfeeding women should consult with a healthcare professional before using the plant, as its constituents may interact with other medications or have adverse effects on fetal or infant development.

What are the horticulural aspects of Cajanus cajan?

Cajanus cajan grow best in full sun with a warm temperature range of 22-30°C. It requires well-drained soil with a pH between 5.5 and 7.0. The plant grows well in tropical and subtropical regions with moderate to high rainfall.

Planting tips for Cajanus cajan include sowing seeds directly in the field or nursery beds 1-2 cm deep and 15-20 cm apart. Seeds germinate in 7-10 days and grow rapidly, requiring staking or support to prevent lodging. It is recommended to sow seeds in rows 1-2 meters apart.

Harvesting Cajanus cajan is typically done when the pods turn yellow or brown, and the peas inside are mature. Harvesting can be done manually by hand-picking or mechanically by machine. The pods can be harvested at any stage, but optimal yields are obtained when harvested in late maturity.

Common pests affecting Cajanus cajan include the pod borer (Maruca testulalis), aphids, and whiteflies. Diseases affecting the plant include fungal infections such as powdery mildew, leaf spot, and rust, as well as viral infections like leaf curl. Regular monitoring and management are essential to prevent infestations.

What are the botanical aspects of Cajanus cajan?

Cajanus cajan is an annual legume with a twining or climbing habit, reaching a height of 3-6 meters. Its stems are slender, hairy, and sometimes woody at the base, with pinnate leaves having 10-12 pairs of leaflets.

The taxonomical classification of Cajanus cajan places it in the family Fabaceae, subfamily Faboideae, tribe Phaseoleae, and genus Cajanus. The species is further divided into two main types: the cultivated type and the wild type.

Cajanus cajan has several variants, including the red grain variety, the green grain variety, and the bush variety. These variants differ in their growth habits, seed color, and yield. The red grain variety is the most common and widely cultivated type.

Cajanus cajan is native to tropical Asia and has been introduced to other parts of the world, including Africa and the Americas. It is widely cultivated in the tropics and subtropics, and is also found in the wild in many countries.

The life cycle of Cajanus cajan begins with germination, which occurs within 10-15 days after sowing. The plant grows rapidly, producing flowers and pods within 60-90 days. The pods contain 3-5 seeds, which mature in 150-180 days after flowering.

What are the historical aspects of Cajanus cajan?

Cajanus cajan is one of the most ancient and widely cultivated legumes in the world. It has been used for centuries as a food source, particularly in Asia, Africa, and the Caribbean, where it is a staple crop. The plant is rich in protein, fiber, and minerals.

In Hindu mythology, the pigeon pea is associated with the goddess Kali, who is said to have created the crop to provide sustenance for humanity. In African cultures, the plant is considered a symbol of fertility and prosperity. The pigeon pea is also mentioned in the ancient Hindu text, the Rigveda.

The pigeon pea is a symbol of abundance, prosperity, and good fortune in many cultures. In Hinduism, it is considered a sacred crop and is often offered as a prayer to the gods. In Africa, the plant is used in traditional ceremonies to mark important life events, such as weddings and harvest festivals.

The pigeon pea is mentioned in several historical texts, including the ancient Indian text, the Mahabharata, and the African epic, the Sundiata. The plant is also documented in the writings of European travelers and traders, such as the Portuguese explorer, Vasco da Gama.

Archaeological evidence of pigeon pea cultivation dates back to the Indus Valley Civilization (c. 3300-1300 BCE). Excavations at the ancient city of Mohenjo-Daro have uncovered evidence of pigeon pea storage and processing facilities. Additionally, ancient Egyptian artifacts, such as pottery and jewelry, feature designs that depict the pigeon pea plant.