HPLC separation and cell effects of GTH. (A) HPLC separation of GTH. The established HPLC method with a C18 column was used for separation of the extracts of the roots of GTH. (B) Cytotoxic effects of GTH on RAW264.7 cells. RAW264.7 cells were incubated at different concentrations of GTH (20-330 μg/ml). The cell viability was measured by MTT tests (n = 3, *= P < 0.05). (C) Cell death with Annexin-V and PI staining analyzed by flow cytometry. Cell death was only induced at GTH concentration of 330 μg/ml. (D) Cell morphology after GTH treatment. RAW264.7 cells were treated with GTH at a concentration of 165 μg/ml for 24 hrs and observed by light microscopy. Photographs show the cells before (a) and after (b) GTH treatment.