Evaluating the cytotoxic effects of the water extracts of four anticancer herbs against human malignant melanoma cells

Figures & data

Figure 1 Percentage increase (mean ± standard deviation) in cytotoxicity of the crude water extracts of Hd, Sb, Lc, and Sn (extraction condition: 1 g herb in 100 mL water) and their respective serial dilutions (2-, 4-, 8-, and 16-fold) against human malignant melanoma cell line A-375.

Notes: The cytotoxicity was measured 24 hr after exposure using the CytoTox 96^® non-radioactive cytotoxicity assay. Cells treated with the culture media were used as negative control. The increase of cytotoxicity was statistically significant only for the crude water extract of Sn (52.8%±13.0%, P<0.01) and its 2-fold dilution (17.3%±2.7%, P<0.01) compared to the control.
Abbreviations: Hd, Hedyotis diffusa; Sb, Scutellaria barbata; Lc, Lobelia chinensis; Sn, Solanum nigrum.

Figure 2 HPLC-MS/MS analysis of the crude water extracts of Hedyotis diffusa, Scutellaria barbata, Lobelia chinensis, and Solanum nigrum (extraction condition: 1 g herb in 100 mL water) in positive ionization mode.

Notes: The total ion current (TIC) chromatograms were presented in panel (A) with H. diffusa, S. barbata, L. chinensis, and S. nigrum shown in gray, red, blue, and green, respectively. A peak region with retention time between 1.8 and 5.5 min, which was highlighted by an arrow, was observed only for the water extracts of H. diffusa and S. nigrum. Abundance of the ions within this peak region was shown in panel (B) for S. nigrum and panel (C) for H. diffusa.
Abbreviations: HPLC-MS/MS, high performance liquid chromatography-tandem mass spectroscopy; cps, counts per second.

Figure 3 HPLC-MS/MS analysis of the crude water extracts of Hedyotis diffusa, Scutellaria barbata, Lobelia chinensis, and Solanum nigrum (extraction condition: 1 g herb in 100 mL water) in negative ionization mode.

Notes: The TIC chromatograms were presented in panel (A) with H. diffusa, S. barbata, L. chinensis, and S. nigrum shown in gray, red, blue, and green, respectively. A peak region with retention time between 5.5 and 6.8 min, which was highlighted by an arrow, was observed only for the water extracts S. nigrum. Abundance of the ions within this peak region for S. nigrum was shown in panel (B).
Abbreviations: HPLC-MS/MS, high performance liquid chromatography-tandem mass spectroscopy; TIC, total ion current; cps, counts per second.

Figure 4 Effects of the crude water extract of Solanum nigrum and its serial dilutions (2-, 4-, 8-, and 16-fold) on intracellular ROS generation (mean ± standard deviation) in human malignant melanoma A-375 cells.

Notes: Treatment with cell culture media was used as negative control. Inhibition of ROS generation by the crude water extract of S. nigrum was statistically significant (P<0.01).
Abbreviation: ROS, reactive oxygen species.

Figure 5 Percentage increase (mean ± standard deviation) in cytotoxicity of the crude water extract of Sn (1 g herb in 100 mL water), TMZ (200 μM), and their combination (Sn+TMZ) against human malignant melanoma cell line A-375.

Notes: The cytotoxicity was measured 24 hr after exposure using the CytoTox 96^® non-radioactive cytotoxicity assay. Cells treated with DMSO, in which TMZ solution was prepared, were used as negative control. The cytotoxicity of Sn+TMZ was statistically significantly increased to 97.0%±3.6% from 31.0%±7.5% for TMZ (P<0.01) and 55.0%±17.6% for Sn (P=0.03).
Abbreviations: DMSO, dimethyl sulfoxide; Sn, S. nigrum; TMZ, temozolomide.