Background: Houttuynia cordata Thunb (HCT) is a medicinal herb used in Southeast Asia. Aim of this work: This study aimed at investigating the cytotoxicity of this plant extract and fractions towards human breast cancer MDA-MB-231 and MCF-7 cells. HCT's phytoactive compounds are determined.
Materials and methods: Cell viability was determined by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The mode of cell death was measured by staining with annexin V-FITC and propidium iodide (PI) employing flow cytometry technique. The oxidative stress was measured by using 2',7'-dihydrodichlorofluorescein diacetate (DCFH-DA) and dihydroethidium (DHE+) fluorescent probes and using a fluorescence microplate reader. HCT phytochemicals were characterized by high performance liquid chromatography (HPLC).
Results: The proliferation of MDA-MB-231 and MCF-7 cells was dramatically decreased by the crude extract and individual fraction of HCT. Ethyl acetate was the solvent fraction with the highest toxicity against MCF-7 cells, followed by dichloromethane, crude, and hexane fractions, respectively, whereas in MDA-MB231 cells, dichloromethane, crude, hexane, and ethyl acetate fractions each had the strongest impact, respectively. The methanol fraction had no effect on either cell line up to 200 μg/ml. The extract and fractions were less harmful to the NIH3T3 normal murine fibroblast cell line. The mode of both cell death was apoptosis evidenced by the increase of cell population stained with annexin V-FITC and PI. The fluorescence probes of both DCFH-DA and DHE in MDA-MB-231 cell line were enhanced. Phenolic acids included chlorogenic acid (CA), gallic acid (GA), transcoumaric acid (TCA), vanillic acid (VA), and syringic acid (SA), as well as flavonoids like quercetin and rutin, were identified as the active phytochemicals in the crude and fractions by using HPLC method.
Conclusion: MDA-MB-231cells underwent apoptosis via oxidative stress when induced with HCT hexane fraction. Phenolic acids and flavonoids were identified in HCT's extract and fractions.
Keywords: Houttuynia cordata Thunb; active phytochemicals; anti-cancer; human breast cancer.