A method for screening and purification of chemosensitizers capable of reversing P-glycoprotein-mediated multidrug resistance from Korean natural plants is provided to inhibit overexpression of P-glycoprotein by inhibiting its function, so that the chemosensitizers kill the cancer cells showing the multidrug resistance without side effects. The method for screening and purification of chemosensitizers capable of reversing P-glycoprotein-mediated multidrug resistance from Korean natural plants comprises the steps of: subjecting the extracts of Korean natural plants to the first silica gel column chromatography using elution solvents containing hexane, dichloromethane and methanol(1:9:1)； subjecting the active fraction to the second silica gel column chromatography using elution solvents containing hexane, dichloromethane and methanol(1:45:1)； subjecting the active fraction to prep-thin layer chromatography； and selecting the substances showing Rf value of 0.4 and brown color in the thin layer chromatography, wherein the Korean natural plants are Tetragonia tetragonoides, Lophatherum gracile Brongn., Lycopodium clavatum var. nipponicum Nakai, Veronica persica Poir. and Houttuynia cordata Thunb.본 발명은 항암제에 내성을 보이는 암세포에 대한 효과적인 항암화학요법을 실시하고자 항암제 내성에 관여하는 P-당단백질의 기능을 억제하기위해 한국산 자생식물 100종을 스크리닝하여 분리한 물질을 이용하여 화학감작제(chemosensitizer)로 유용하게 활용할 수 있다.
