Plant Alkaloid Effective in Multidrug Resistant Cancer Cells

L-Tetrahydropalmatine ( L-THP) is an alkaloid found in several plant species such as Corydalis and Stephania. Corydalis Tuber ( Corydalis yanhusuo) containing L-THP has been used for traditional Chinese pain medicine. Since L-THP antagonizes dopamine D ₁ /D ₂ receptors and acts on dopamine D ₃ receptors, as well as α-adrenergic and serotonin receptors, it may have utility for treating opioid addiction. ^1,2)
Furthermore, it has been reported that L-THP shows activity against antineoplastic resistant cancer cells. ³⁾ In antineoplastic resistant cells, p-glycoprotein (P-gp), multidrug resistance-associated protein 1 (MRP1), and breast cancer resistance protein (BCPR), pump some antineoplastic agents out of cells. The P-gp-inhibitory activity of L-THP results in increased doxorubicin cytotoxicity in P-gp-mediated multidrug resistant cancer cells.