Cytotoxic phytochemicals from the crude extract of Tetrapleura tetraptera fruits towards multi-factorial drug resistant cancer cells

J Ethnopharmacol. 2021 Mar 1:267:113632. doi: 10.1016/j.jep.2020.113632. Epub 2020 Nov 27.

Abstract

Ethnopharmacological relevance: Tetrapleura tetraptera is an African medicinal spice used in traditional medicine to treat several ailments including cancer.

Aim of the study: The present study was designed to evaluate the cytotoxicity of the dichloromethane-methanol (1:1) extract of the fruits of Tetrapleura tetraptera (TTF) and its constituents: (3R, 4S)-3,4-dimethyloxetan-2-one (1), luteolin (2), stigmasterol (4), 3-O-[6'-O-undecanoyl-β-D-glucopyranosyl]stigmasterol (6), olean-12-en-3-β-O-D-glucopyranoside (7), 3-O-β-D-glucopyranosyl-(1 → 6)-β-D-glucopyranosylurs-12-en-28-oic acid (8), 3-O-β-D-glucopyranosyl-(1 → 3)-β-D-glucopyranosyl-27-hydroxyolean-12-ene-28-oic acid (9), methyl-O-β-D-glucopyranoside (10), β-D-fructofuranosyl-(2 → 1)-β-D-glucopyranoside (11) towards a panel of cancer cell lines including MDR phenotypes. The cellular mode of induction of apoptosis by TTF and compound 7 was further investigated.

Materials and methods: The resazurin reduction assay (RRA) was applied to determine the cytotoxicity of the studied samples. The cell cycle (PI staining), apoptosis (annexin V/PI staining), mitochondrial membrane potential (MMP; JC-1) and reactive oxygen species (ROS; H2DCFH-DA) were measured by flow cytometry. Column chromatography was used for the purification of TTF, whilst nuclear magnetic resonance (NMR) spectroscopic analysis was applied for structural elucidation.

Results: The botanical, TTF and the phytochemicals, 2, 7, 8 and 9 as well as doxorubicin exerted cytotoxicity against 9 cancer cell lines including drug-sensitive and drug resistant phenotypes. TTF, compound 7 and doxorubicin were the most active samples, and displayed IC50 values ranging from 10.27 μg/mL (in CCRF-CEM leukemia cells) to 23.61 μg/mL (against HCT116 p53-/- colon adenocarcinoma cells) for TTF, from 4.76 μM (against CCRF-CEM cells) to 12.92 μM (against HepG2 hepatocarcinoma cells) for compound 7, and from 0.02 μM (against CCRF-CEM cells) to 122.96 μM (against CEM/ADR5000 cells) for doxorubicin. TTF induced apoptosis in CCRF-CEM cells through MMP alteration and increased ROS production while compound 7 induced apoptosis mediated by caspases activation, MMP alteration and increased ROS production.

Conclusion: Tetrapleura tetraptera and some of its constituents, mostly compound 7 are good cytotoxic natural products that should be explored in depth to develop new drugs to fight cancers.

Keywords: Apoptosis; Cancer; Cytotoxicity; Fabaceae; Multi-drug resistance; Tetrapleura tetraptera.

Publication types

  • Comparative Study

MeSH terms

  • Antineoplastic Agents, Phytogenic* / isolation & purification
  • Antineoplastic Agents, Phytogenic* / pharmacology
  • Apoptosis* / drug effects
  • Caspases / metabolism
  • Dose-Response Relationship, Drug
  • Drug Resistance, Multiple*
  • Drug Resistance, Neoplasm*
  • Fruit* / chemistry
  • HCT116 Cells
  • Hep G2 Cells
  • Humans
  • Inhibitory Concentration 50
  • Membrane Potential, Mitochondrial / drug effects
  • Neoplasms* / drug therapy
  • Neoplasms* / metabolism
  • Neoplasms* / pathology
  • Oxidative Stress / drug effects
  • Phytochemicals* / isolation & purification
  • Phytochemicals* / pharmacology
  • Plant Extracts* / isolation & purification
  • Plant Extracts* / pharmacology
  • Reactive Oxygen Species / metabolism
  • Signal Transduction
  • Tetrapleura* / chemistry

Substances

  • Antineoplastic Agents, Phytogenic
  • Caspases
  • Phytochemicals
  • Plant Extracts
  • Reactive Oxygen Species