Siamese Cassia

Scientific name: Cassia siamea

POWO Status: Tree

IUCN Red List threat level: Least Concern

GPS Location: 17° 42′ 54.69″ N, 64° 49′ 52.40″ W

Medicinal Uses

Cassia siamea (Siamese Cassia) is a traditional medicinal plant used globally for its diverse properties, primarily as a laxative, antimalarial, anti-inflammatory, antioxidant, and for liver support, with extracts from leaves, bark, and flowers showing benefits for diabetes, pain, microbial infections, and even potential anti-cancer/viral effects, though more clinical trials are needed. Its rich phytochemicals, including flavonoids and anthraquinones, contribute to these therapeutic actions, with compounds like barakol being key.

Traditional & Pharmacological Uses:

Digestive Health: Used as a laxative, sleeping aid (Thailand), and for loss of appetite, often requiring boiling.
Antimalarial: Extracts show promise against Plasmodium falciparum, supporting traditional use in Africa and Asia.
Anti-inflammatory & Analgesic: Decoctions used for rheumatism, swelling, and pain relief, validated by studies showing reduced inflammation.
Antidiabetic: Leaf extracts help lower blood glucose and improve insulin sensitivity in animal models.
Antioxidant: High levels of antioxidants protect against cell damage, relevant for chronic diseases.
Liver Support (Hepatoprotective): Used for liver troubles and shows potential in protecting against liver damage.
Antimicrobial: Extracts exhibit activity against bacteria like E. coli and Staphylococcus aureus.
Cardiovascular: Shows potential for blood pressure reduction and vasodilation.

Key Compounds:

Barakol & Anhydrobarakol: Chromone derivatives, major active compounds.
Cassiamins (A & B): Bianthraquinones with various activities, including anti-obesity.
Anthraquinones (Emodin, Chrysophanol): Contribute to laxative and other effects.
Flavonoids & Phenolics: Provide antioxidant power.

Important Consideration:

While promising, many studies are preclinical (animal/lab), so human clinical evidence for some uses is limited.
Edible parts, like leaves and pods, must be boiled and the water discarded before consumption.

Observations:

Phenological Markers – Cassia siamea (Siamese Senna)

Family: Fabaceae (Legume family)
Common Names: Siamese Senna, Yellow Cassia, Kassod Tree, Cassod Tree
Habitat: Native to Southeast Asia, especially Thailand and Myanmar; widely planted in tropical and subtropical regions as an ornamental and shade tree, including in the Caribbean. Tolerant of poor soils and drought.

Phenological Markers:

Flowering Period:
Year-round flowering is possible in warm climates, but peaks typically occur in late summer to fall (August to October). Bright yellow, 5-petaled flowers appear in dense terminal clusters.
Fruiting Period:
Seed pods develop shortly after flowering and mature in late fall to early winter (October to January). The long, flat, brown seed pods can be up to 30 cm in length and contain several hard, disk-like seeds.
Leaf Fall:
Semi-evergreen. May shed some leaves during the dry season (January to March) or under drought stress but generally retains foliage year-round in humid climates.
Budding Period:
New growth begins in early to mid-spring (March to May), often accompanied by budding inflorescences, especially after light rains.

Key Features:

Leaves: Even-pinnate, compound leaves with 6–12 pairs of leaflets. Leaflets are oblong and dark green, with new leaves often appearing reddish.
Flowers: Showy, bright yellow with conspicuous stamens; a popular choice for avenue or ornamental planting.
Fruits: Long, flat, dark brown pods containing 20+ seeds. Pods often remain on the tree for weeks after maturing.

Additional Notes:

Cassia siamea is commonly used in urban landscaping due to its fast growth, symmetrical crown, and drought tolerance.
Leaves, pods, and seeds contain alkaloids and are considered toxic if consumed in large quantities, although small amounts are sometimes used in traditional medicine (usually cooked to reduce toxicity).
It contributes to soil stabilization and is sometimes used in agroforestry for shade and green manure.