Journal of Carcinogenesis & Mutagenesis

Abstract

Calendula officinalis Extracts Protect against H2O2 Induced Chromosome Damage on HacaT Human Skin Cells

Abdullah M Alnuqaydan, Claire E Lenehan, Rachel R Hughes and Barbara J Sanderson

Background: Calendula officinalis extracts contain antioxidant compounds. The extracts tested in the current study protect against reactive oxygen species (ROS) induced cytotoxic activity towards human cells. Objective: To determine the ability of Calendula officinalis extracts to protect against H2O2 induced chromosome damage on HaCaT human skin cells. Methodology: The chromosome damage protection by four Calendula officinalis extracts was investigated in vitro using a dose-response (0.125, 0.5 and 1.0% (v/v)) on HaCaT human skin cells. Two water/ethanol based proprietary calendula extracts A and B and two proprietary aqueous calendula extracts C and D from Biodynamically grown plants were examined. Extracts were characterised using Folin-Ciocalteau and DPPH assays. Protection of extracts against chromosome damage was measured via micronuclei induction using the cytokinesis-blocked micronucleus assay. No genotoxicity was induced by the extracts themselves. Cells were also exposed to the Calendula extracts for 47 h before being exposed to an oxidative stress (300-μM hydrogen peroxide for 1 h). Results: The oxidative stress induced micronuclei (MNi) at a frequency significantly higher (P<0.05; range=20-25 MNi/1000 binucleated cells, n=3) than the background frequency (media alone control; MNi range=7-13 MNi/1000 binucleated cells, n=3). When the cells were pre-treated with extracts before the oxidative stress, the level of protection against chromosomal damage by all Calendula extracts was significant (P<0.05). The frequency of MNi in the presence of extracts was reduced by an average increment of 20 MNi/1000 BN cells to 2-9 MNi/1000 BN cells at all doses tested. Conclusion: The Calendula extracts protected against the chromosomal damage induced by oxidative stress in vitro. Such form of genetic damage has been linked with carcinogenesis.