Gamma-sitosterol was administered to diabetic rats as a once-daily oral dose of 20 mg/kg bw for 21 days. The dosing regime resulted in significant decrease in blood glucose and glycosylated hemoglobin coupled with a significant increase in plasma insulin level, body weight, and food intake. Gamma-sitosterol also exhibited antihyperlipidemic activity as evidenced by a significant decrease in serum total cholesterol, triglycerides and VLDL-cholesterol along with increased HDL-cholesterol levels.

Human Peripheral Blood Mononuclear Cells (PBMC) were isolated from sodium heparin anticoagulated venous blood from a blood bank. Cells were suspended at a concentration of 10^6 cells/mL in RPMI-1640 medium with 2 mM L-glutamine and 25 mM HEPES, supplemented with 10% FBS, 5 μg/mL phytohemagglutinin (PHA), 100 μg/mL streptomycin, and 100 U/mL penicillin. Cells were treated with plant ethanol extracts from the genus Lagerstroemia for 4 hours; gamma-sitosterol content varied from 14.70 - 34.44%. Cell viability was determined to reveal the cytotoxicity of the plant extracts. Most plant extracts exhibited modest cytotoxicity with the exception of extracts from L. speciosa which exhibited an IC50 of 0.24 mg/mL corresponding to an LD50 of 811.78 mg/kg, which is in the range of WHO Class III toxic chemicals.