- 1
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan,
Saskatoon, SK; Department of Biomedical and Molecular Sciences, Queen's
University, Cancer Biology & Genetics Division, Queen's Cancer
Research Institute, Kingston, ON, Canada.
- 2
- Drug Discovery and Development Research Group, College of Pharmacy and Nutrition, University of Saskatchewan, Saskatoon, SK.
Abstract
Malignant
melanoma (MM) is the most dangerous type of skin cancer, killing more
than 1,100 people each year in Canada. Prognosis for late stage and
recurrent MM is extremely poor due to insensitivity to chemotherapy
drugs, and thus many patients seek complementary and alternative
medicines. In this study, we examined four commonly used anticancer
herbs in traditional Chinese medicine, Hedyotis diffusa, Scutellaria barbata, Lobelia chinensis, and Solanum nigrum, for their in vitro antitumor effects toward human MM cell line A-375. The crude water extract of S. nigrum
(1 g of dry herb in 100 mL water) and its 2-fold dilution caused
52.8%±13.0% and 17.3%±2.7% cytotoxicity in A-375 cells, respectively (P<0.01). The crude water extract of H. diffusa caused 11.1%±12.4% cytotoxicity in A-375 cells with no statistical significance (P>0.05). Higher concentrated formulation might be needed for H. diffusa
to exert its cytotoxic effect against A-375 cells. No cytotoxicity was
observed in A-375 cells treated with crude water extract of S. barbata and L. chinensis. Further high performance liquid chromatography-tandem mass spectroscopy analysis of the herbal extracts implicated that S. nigrum and H. diffusa
might have adopted the same bioactive components for their cytotoxic
effects in spite of belonging to two different plant families. We also
showed that the crude water extract of S. nigrum reduced
intracellular reactive oxygen species generation in A-375 cells, which
may lead to a cytostatic effect. Furthermore, synergistic effect was
achieved when crude water extract of S. nigrum was coadministered with temozolomide, a chemotherapy drug for skin cancer.
KEYWORDS:
HPLC-MS/MS; cytotoxicity; herbal extract; malignant melanoma; reactive oxygen species
