Cancer cell specific cytotoxic effect of Rhoeo discolor extracts and solvent fractions

J Ethnopharmacol. 2016 Aug 22:190:46-58. doi: 10.1016/j.jep.2016.05.051. Epub 2016 May 25.

Abstract

Ethnopharmacological relevance: Traditional or folk medicine has led to the discovery of important bioactive substances used in several health-related areas. Phytochemicals in Rhoeo discolor (R. discolor) extracts have proven to have important cancer cell specific cytotoxic activity. In the present research, we determined the cytotoxic effect of extracts of R. discolor, a plant commonly used in Mexico for both medicinal and ornamental purposes.

Aim of the study: We evaluated the cytotoxic effects against three representative human cancer cell lines: HT-29 colon cancer, Hep-G2 liver cancer and PC-3 prostate cancer cell lines, as well as a control fibroblast cell line NIH 3T3.

Materials and methods: Ten different crude extracts were tested along with fractions derived from the five most bioactive crude extracts. Analytical data, HPLC-MS-TOF, revealed a high content of phenolic compounds such as anthocyanins, ferulic, vanillic, chlorogenic and p-coumaric acid in the extracts. Phenolic compounds have previously been reported as health beneficial with antioxidant and potential cancer specific cytotoxic effects.

Results: Studies revealed that low concentrations of these crude bioactive extracts (10µg/ml) and their fractions (50µg/ml) were effective as cancer specific cytotoxic agents, since they caused a significant proliferation inhibition on cancer cell lines (up to 94.2% in HT-29, 92.9% in Hep-G2 and 61.8% in PC-3 of apoptosis induction) with little harm to the control cell line (no higher than 28.3% apoptosis induction), and, importantly, the most effective extracts were mainly water, methanol and ethanol based.

Conclusions: These results suggest that a diet containing these compounds may function as a medical aid or chemoprotective.

Keywords: Cancer; Cytotoxic; Phenolic compounds – antioxidant; Rhoeo discolor; Traditional medicine.

MeSH terms

  • Animals
  • Antineoplastic Agents, Phytogenic / isolation & purification
  • Antineoplastic Agents, Phytogenic / pharmacology*
  • Antineoplastic Agents, Phytogenic / toxicity
  • Apoptosis / drug effects
  • Cell Proliferation / drug effects
  • Chromatography, High Pressure Liquid
  • Dose-Response Relationship, Drug
  • Ethanol / chemistry
  • HT29 Cells
  • Hep G2 Cells
  • Humans
  • Mass Spectrometry
  • Methanol / chemistry
  • Mice
  • NIH 3T3 Cells
  • Neoplasms / drug therapy*
  • Neoplasms / pathology
  • Phytotherapy
  • Plant Extracts / isolation & purification
  • Plant Extracts / pharmacology*
  • Plant Extracts / toxicity
  • Plant Leaves
  • Plants, Medicinal
  • Solvents / chemistry*
  • Tradescantia / chemistry*
  • Water / chemistry

Substances

  • Antineoplastic Agents, Phytogenic
  • Plant Extracts
  • Solvents
  • Water
  • Ethanol
  • Methanol