Background: The pericarp extract of mangosteen (Garicinia mangostana) Linn, alpha-mangostin, is known to have beneficial effects on the body which includes anti-inflammatory, as well as anti-diabetic properties. Extramedullary hematopoiesis is the process whereby blood cellular components are formed outside the bone marrow under stressful conditions.

Objective: To evaluate the effects of subacute toxicity induced by alpha-mangostin in rat spleen.

Material and Method: A total of 40 Wistar rats were used to study histopathological changes in the spleen after being exposed to alpha-mangostin for one month. The rats were equally divided into four groups: treated male (n = 10); treated female (n = 10); control male (n = 10); and control female (n = 10). The treated group received alpha-mangostin pericarp extract diluted in 0.1% carboxymethylcellulose (0.1% CMC) in a concentration of 100 mg/5 ml, and 100 mg/kg/day alpha-mangostin was introduced to the rats via intra-peritoneal injection. The control group received 0.1% CMC five days per week for one month as standard treatment. Splenic tissues were collected at the end of the study period. Paraffin sections were examined by H&E and immunohistochemical stainings. Body weight was measured before and after the intervention for all groups.

Results: After exposure to alpha-mangostin, the treated groups showed increased platelet formation, myeloid progenitor cells, and megakaryocyte in the spleen as well as decrease in the body weight of male rats when compared to the control groups. Immunohistochemical study confirmed that the newly formed blood cells were from myeloid and erythroid precursor cells.

Conclusion: Exposure to high dose of alpha-mangostin marked the presence of extramedullary hematopoiesis which is the formation of blood cellular components outside the bone marrow.

Keywords: Extramedullary hematopoiesis, Alpha-mangostin, Spleen, Subacute toxicity