Herb's Introduction
Senna siamea (Lam.) H.S.Irwin & Barneby, commonly known as the Siamese Senna or Kassod Tree, is a medium-sized, evergreen tree belonging to the family Fabaceae (formerly Caesalpinioideae). It is native to South and Southeast Asia, including Sri Lanka, Indo-China, Myanmar, and Thailand, but has been widely introduced and cultivated throughout the tropics, particularly in Africa and various parts of Asia. Beyond its role as an ornamental tree, windbreak, and source of timber and firewood, Senna siamea holds significant traditional medicinal value across its native and adopted regions, where various parts of the plant, including the leaves, stems, roots, flowers, and seeds, are utilized in herbal remedies.
Name in Different Countries
Senna siamea is recognized by numerous common names, reflecting its widespread distribution and cultural significance. Some of these names include: Preferred Common Name: Yellow Cassia, Siamese Senna, Kassod Tree. English: Thailand Shower, Thai Copper Pod, Iron Wood, Siamese Cassia. Amharic (Ethiopia): yeferenji digita Creole: kasya Bahasa Indonesia: Johar Hindi (India): Seemia Japanese: タガヤサン (Tagayasan) Kannada (India): Hiretangedi, Motovolanyaro Malay: Ceubrék Malayalam (India): Manjakonna, Manjakonnei Marathi (India): कसोद Kassod Tamil (India): Sinna konnai Telugu (India): Seema tangedu, Kurumbi Thai (Thailand): ขี้เหล็ก (khilek)
Terminology
Scientific Name: Senna siamea (Lam.) H.S.Irwin & Barneby Family: Fabaceae (Leguminosae-Caesalpinioideae) Synonyms: Cassia siamea Lam., Cassia florida Vahl, Cassia sumatrana Roxb. ex Hornem., Chamaefistula gigantea (Bertero ex DC.) G.Don, and others. The older name Cassia siamea is still commonly used. Phytoconstituents: The plant is rich in various bioactive compounds, including Chromone alkaloids (e.g., Barakol and Anhydrobarakol, Cassiarin A-B), Anthraquinones (e.g., Emodin, Chrysophanol), Bianthraquinones (e.g., Cassiamin A-B), Flavonoids, Phenolics, Tannins, Alkaloids, Saponins, and Steroids. Barakol is a key compound known for its sedative and anxiolytic effects.
Availability
Senna siamea is a widely distributed and fast-growing tree in tropical and subtropical regions globally. Native Range: South and Southeast Asia, including India, Sri Lanka, Myanmar, Thailand, Cambodia, and Vietnam. Introduced Range: It is extensively cultivated throughout tropical Africa, the Caribbean, and other tropical regions, valued for its environmental (shade, windbreak, agroforestry) and utilitarian purposes. In the Context of Nepal: While not explicitly listed as one of the commonly screened medicinal plants in some regional studies of Nepal, its wide introduction and traditional usage in neighboring South Asian countries suggest that it may be present in the lower altitude, tropical, or subtropical regions of the country, possibly as an introduced species for agroforestry or ornamental purposes. However, specific documented traditional uses of this plant within the various ethnic communities of Nepal were not highlighted in the available focused snippets.
External Look
Senna siamea is an attractive, medium-sized, evergreen tree with a distinctive appearance: Size and Habit: Typically grows to a height of 10 to 18 meters, but can reach up to 30 meters under exceptional conditions. It has a dense, rounded crown and a relatively short, straight trunk. Bark: The bark is generally grey or light brown, smooth when young, becoming slightly fissured with age. Leaves: The leaves are alternate and pinnately compound, measuring about 15–30 cm long. Each leaf has 6–14 pairs of oblong, dark green leaflets, each 3–7 cm long and 12–20 mm wide, with a small bristle tip. Flowers: A key ornamental feature. The flowers are bright yellow, about 3 cm across, and borne in numerous large, upright, pyramidal clusters (panicles) up to 60 cm long at the ends of the branches. The tree often flowers profusely and for a long period throughout the year in certain climates. Fruit (Pods): The fruit are long, flat, strap-shaped pods, 15–25 cm long and 12–20 mm broad, dark brown when ripe, and contain 20–30 shiny, dark brown, bean-shaped seeds.
Healing Properties
Traditional medicine and preliminary scientific studies suggest Senna siamea possesses a diverse range of healing properties: Antimicrobial and Antiparasitic: It has been shown to exhibit antibacterial, antifungal, and antiparasitic activity, including traditional use against intestinal worms (vermicide) and scabies. Sedative and Anxiolytic: The chromone alkaloid, Barakol, found in the leaves, is primarily credited with traditional use as a natural sedative, sleep aid (hypnotic), and for reducing anxiety. Anti-inflammatory and Analgesic: Extracts have demonstrated properties that help reduce inflammation and pain. Laxative and Purgative: The presence of anthraquinones (like chrysophanol and emodin) gives it laxative properties, traditionally used to manage constipation. Antimalarial and Antipyretic (Fever-Reducing): It is extensively used in folk medicine, particularly in Africa and Asia, to treat malaria and periodic fevers. Antidiabetic and Hypotensive: Traditional use includes lowering blood sugar levels and managing hypertension (high blood pressure). Antioxidant and Hepatoprotective: The plant's phenolic and flavonoid content contributes to its antioxidant activity, which may help protect against oxidative stress. Other Traditional Uses: It is also traditionally used as a blood cleaning agent and for treating jaundice, typhoid fever, abdominal pain, menstrual pain, and digestive and genitourinary disorders.
Advantages
The advantages of Senna siamea stem from its chemical composition and widespread traditional use: Multi-Spectrum Activity: The presence of numerous bioactive compounds, such as chromone alkaloids, anthraquinones, and flavonoids, gives it a broad range of therapeutic potential (e.g., sedative, antimalarial, antidiabetic, antimicrobial). Natural Laxative: It offers a traditional, non-prescription option for relieving constipation, comparable in effectiveness to some conventional laxatives when properly dosed. Folk Sleep Aid: Its use as a sleep aid is a significant advantage in traditional practice, attributed to the anxiolytic and sedative effects of Barakol. Affordability and Availability: Being a fast-growing and widespread tree in the tropics, the raw plant material is often easily accessible and affordable for local communities. Nutritional Value: The leaves also contain nutrients, further supporting its use as an edible plant (when properly prepared).
Uses
The uses of Senna siamea can be categorized into medicinal, culinary, and non-medicinal: Medicinal Uses (Traditional and Reported): Constipation: Used as a laxative, particularly the leaves and heartwood. Fever and Malaria: Decoctions of leaves, stems, roots, seeds, and flowers are used to treat periodic fever and malaria. Insomnia and Anxiety: Leaves are traditionally used as a sleep aid and to reduce anxiety (sedative/anxiolytic). Diabetes and Hypertension: Used traditionally to help manage blood sugar levels and high blood pressure. Infectious Diseases: Used for typhoid fever, syphilis, herpes, and other genitourinary disorders, and has shown antimicrobial activity against various bacteria. Digestive and Abdominal Issues: Used for abdominal pain, jaundice, and as a 'blood cleaning agent.' Parasitic Infections: The fruit is traditionally used against intestinal worms, and heartwood decoction against scabies. Culinary Uses: Edible Leaves and Flowers: In Thailand, young leaves, tender pods, seeds, and flowers are popular in cuisine, most famously in the Thai curry known as Kaeng Khilek. Important Note: To remove toxins, particularly the compound Barakol, the leaves, pods, and seeds must be thoroughly boiled and the water discarded multiple times before consumption. Other Uses: Agroforestry and Ornamentation: Planted as a shade tree, windbreak, hedge, and for its ornamental value due to its bright yellow flowers. Wood/Timber: Provides good quality timber, sometimes referred to as Pheasantwood, used in carpentry, cabinet making, and for making high-quality charcoal. Tanning and Dyeing: All parts of the plant can be used for tanning leather due to their tannin content.
Using Way
The traditional methods of using Senna siamea predominantly involve preparing decoctions or formulating the dried plant material: Decoction (Boiling): This is the most common preparation method, especially for antimalarial, fever, and liver disorders. Method: Fresh or dried leaves, bark, or other parts are boiled in water (e.g., 20 minutes in 1 liter of water). The liquid is then strained and consumed. In some regions, like Burkina Faso, this decoction is drunk with lemon juice. Capsules/Pills: In modern traditional practice, dried leaves are sometimes ground and encapsulated for use as a laxative or sleeping pill. Topical Application: Decoction of the heartwood has been used as a wash against scabies. Fresh leaves have also been used locally to repel or kill insects. Culinary Preparation: For food use (e.g., Thai curries), the young leaves and pods must be thoroughly boiled, and the water is typically discarded multiple times to reduce the potentially toxic compounds, such as Barakol. Chewing: In some traditions, leaves are chewed and swallowed to treat abdominal pain. ⚠️ Cautions and Toxicity: It is crucial to be aware that while medicinally useful, long-term or high-dose oral consumption of Senna siamea is potentially UNSAFE and has been associated with hepatotoxicity (liver damage), primarily due to the compound Barakol. In Thailand, a herbal hypnotic containing S. siamea was withdrawn due to reported cases of acute hepatitis. For medicinal use, short-term usage and appropriate preparation methods (like discarding the water during cooking) are essential. Consultation with a healthcare professional or qualified herbalist is strongly recommended before medicinal use.
Conclusion
Senna siamea, or Kassod Tree, is a prominent and versatile tropical plant with a long history of use in traditional medicine throughout Asia and Africa. Its therapeutic profile is broad, encompassing activities such as anti-malarial, anti-diabetic, anti-inflammatory, and notably, acting as both a natural laxative and a sedative/anxiolytic agent due to the presence of key phytochemicals like Barakol and anthraquinones. While its widespread use for various ailments, including fever, abdominal pain, and hypertension, underscores its significance in folk healthcare, it is imperative to acknowledge the associated toxicity risks, particularly potential hepatotoxicity from Barakol with prolonged or excessive use. The tree also contributes significantly to local economies and food security (with careful preparation). Further clinical research is warranted to validate the safety, efficacy, and appropriate dosage for its diverse traditional applications, ensuring safe integration into modern herbal and pharmaceutical practices.
