Houttuynia cordata Thunb extract induces cytotoxicity in human nasopharyngeal carcinoma cells: Raman spectroscopic studies

The molecular mechanisms of cytotoxicity induced by Houttuynia cordata Thunb (HCT) in nasopharyngeal carcinoma (NPC) cells was investigated by Raman spectroscopy (RS). The average Raman spectra of cell groups treated with HCT (0, 62.5, 125, 250, and 500 μg ml−1) for 24 h were measured separately. Compared to the control group, the intensities of the selected bands (1002, 1338, and 1448 cm−1) related to protein, DNA, and lipid in the treatment groups decreased obviously as the concentration of HCT increased. Both cell groups treated with 250 and 500 μg ml−1 of HCT could be differentiated from the control group by principal component analysis (PCA) combined with linear discriminate analysis (LDA) with a diagnostic accuracy of 100%, suggesting that cytotoxicity occurred and that 250 μg ml−1 was the proper dose for treatment. Simultaneously, the Raman spectra of cells treated with different treatment times with 250 μg ml−1 of HCT were obtained. We can get that treatment with HCT decreased cell viability in a dose and time-dependent fashion. The results indicated that the RS combined with PCA–LDA can be used for pharmacokinetics studies of HCT in NPC cells, which could also provide useful data for clinical dosage optimization for HCT.