SiamesecassiaThe Senna siamea, also known as Siamese cassia, kassod tree, cassod tree, and cassia tree, is a legume in the subfamily Caesalpinioideae. It is native to South and Southeast Asia, although its exact origin is unknown. It is a medium-sized, evergreen tree growing up to 18 m (60 ft) with yellow flowers.
The tree bark contains a high percentage of tannins and its extract is used in leather production. The bark is also used in the traditional medicine system to treat fever, diarrhea, and rheumatism. Senna siamea is one of the most important trees species in Thailand, where it has usually grown along the roadsides or as a shade tree in rubber plantations.
The leaf of Senna siamea is prohibited to be used as a vegetable in Thailand due to the possible risk of poisoning. Two cases of fatal food poisoning have been reported after consuming the leaves of this plant. The first case involved two children who consumed the leaves in a northern province. The second case was reported in Bangkok where three adults ate the cooked leaves and died of severe poisoning.
In both cases, postmortem examination showed congestion and hemorrhage of internal organs with the blue coloration of postmortem skin and mucous membrane. The plant contains several highly toxic compounds including a compound known as sennoside B, which is a cardiac glycoside. In traditional medicine, the plant has been used to treat fever, diarrhea, and rheumatism.
This tree can be grown easily from seed. Seeds should be planted in pots of fertile soil with high sand content and left outside during the wet season to germinate. The seedlings should be planted outside during the wet season and brought in when it starts to get cold, with a little protection from frost.
The tree grows best in warmer temperatures and cannot grow in freezing conditions or areas with frequent rainfall. Propagation of this tree by cuttings is also possible. The tree can grow in a wide range of soils, ranging from acidic to alkaline with a pH level of 4-8. It is commonly found growing on the banks of rivers and dams as well as around rice fields and agricultural areas.
The tree is considered valuable due to its medicinal properties and wood quality. This plant has been included as one of the target species for conservation and sustainable management due to its high medicinal value.
The phytochemical components of Senna siamea include phenolics, flavonoids, tannins, alkaloids, and saponin glycosides. Several biologically active compounds such as sennoside B, sennoside A, sennoside C, rhein, aloe-emodin anthrone glucosides, chebulagic acid, ellagic acid derivatives have been isolated from the leaves of Senna siamea.