alpha-Spinasterol isolated from the root of Phytolacca americana and its pharmacological property on diabetic nephropathy.

Based on an inhibitory activity-guided fractionation for the high glucose-induced proliferation of glomerular mesangial cells (GMCs), chloroform extracts of the roots of Phytolacca americana were found to contain alpha-spinasterol (C (29)H (48)O), a delta (7)-sterol. This phytosterol proved to be a potent inhibitor (IC (50) = 3.9 x 10 (-12) g/mL, 9.5 pmol/L) of glomerular mesangial cell proliferation caused by high-ambient glucose (5.6 mM vs. 25 mM), and its inhibitory potency was about 1,000 times higher than that of simvastatin, an HMG-CoA reductase inhibitor used as a positive control. alpha-Spinasterol also significantly reduced the increases of serum triglycerides, renal weight and urinary protein excretion in streptozotocin-induced diabetic mice, and these were comparable to the results observed in insulin-treated diabetic mice. Therefore, the results obtained in this study suggest that alpha-spinasterol has a significant therapeutic potential to modulate the development and/or progression of diabetic nephropathy.