In vitro antitumor actions of extracts from endemic plant Helichrysum zivojinii

Ivana Z Matić,Milka Jadranin,Željko Žižak,Slobodan Milosavljević,Ivana Aljančić,Zorica D Juranić,Vlatka Vajs

doi:10.1186/1472-6882-13-36

Abstract

BackgroundThe aim of this research was to determine the intensity and mechanisms of the cytotoxic actions of five extracts isolated from the endemic plant species Helichrysum zivojinii Černjavski & Soška (family Asteraceae) against specific cancer cell lines. In order to evaluate the sensitivity of normal immunocompetent cells implicated in the antitumor immune response, the cytotoxicity of extracts was also tested against healthy peripheral blood mononuclear cells (PBMC).MethodsThe aerial parts of the plants were air-dried, powdered, and successively extracted with solvents of increasing polarity to obtain hexane, dichloromethane, ethyl-acetate, n-butanol and methanol extracts. The cytotoxic activities of the extracts against human cervix adenocarcinoma HeLa, human melanoma Fem-x, human myelogenous leukemia K562, human breast adenocarcinoma MDA-MB-361 cells and PBMC were evaluated by the MTT test. The mode of HeLa cell death was investigated by morphological analysis. Changes in the cell cycle of HeLa cells treated with the extracts were analyzed by flow cytometry. The apoptotic mechanisms induced by the tested extracts were determined using specific caspase inhibitors.ResultsThe investigated Helichrysum zivojinii extracts exerted selective dose-dependent cytotoxic actions against selected cancer cell lines and healthy immunocompetent PBMC stimulated to proliferate, while the cytotoxic actions exerted on unstimulated PBMC were less pronounced. The tested extracts exhibited considerably stronger cytotoxic activities towards HeLa, Fem-x and K562 cells in comparison to resting and stimulated PBMC. It is worth noting that the cytotoxicity of the extracts was weaker against unstimulated PBMC in comparison to stimulated PBMC. Furthermore, each of the five extracts induced apoptosis in HeLa cells, through the activation of both intrinsic and extrinsic signaling pathways.ConclusionExtracts obtained from the endemic plant Helichrysum zivojinii may represent an important source of novel potential antitumor agents due to their pronounced and selective cytotoxic actions towards malignant cells.

Highlights

The aim of this research was to determine the intensity and mechanisms of the cytotoxic actions of five extracts isolated from the endemic plant species Helichrysum zivojinii Černjavski & Soška against specific cancer cell lines
The ethylacetate extract (3) and n-butanol extracts (4) presented 1H NMR spectra with approximately identical groups of signals in the regions δ 12.5– 13.9, δ 5.9-8.1, and δ 4.7–5.5
The 1H NMR spectrum of the most abundant methanol extract (5), recorded in dimethyl sulfoxide (DMSO)-d6, resembles the spectra of the ethyl-acetate and n-butanol extracts by the presence of signals in the region δ 5.9–8.1, as well as by the presence of a signal at δ 13.9; it differs from the last two spectra by possessing a more pronounced region at δ 4.7–5.5, which is responsible for the protons of sugar units

Summary

Introduction

The aim of this research was to determine the intensity and mechanisms of the cytotoxic actions of five extracts isolated from the endemic plant species Helichrysum zivojinii Černjavski & Soška (family Asteraceae) against specific cancer cell lines. Some of the plant species from the large genus Helichrysum are used in different regions of the world in traditional medicine for treating wounds, respiratory tract infections and gastro-intestinal disorders [5,6,7,8]. This plant genus is a valuable source of several different secondary metabolites/phytochemicals, such as flavonoids, acetophenones, phloroglucinols, pyrones, diterpenes and sesquiterpenes [5]. A search through the literature suggests that plants from the genus Helichrysum could be a significant source of compounds with potential anticancer activities [17,18,19,20]

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