DNA protective and DNA damage activity of induced peanut hairy root crude extract with antioxidant and pro-oxidant properties

Key message The pre-exposure of methyl jasmonate (MJ) plus methyl-beta-cyclodextrin (CD) followed by cadmium (Cd) extensively induced highest ferric reducing antioxidant power (FRAP) in the hairy root culture. The low concentration of crude extract exhibited DNA-protective activity. However, the pro-oxidant activity of crude extract is increased in a concentration-dependent manner. A combination of elicitors was applied to enhance secondary metabolite production in peanut hairy root culture. The increasing biosynthesis of secondary metabolites with high antioxidant capacity could be a significant mechanism in the defence response of plants to neutralise cellular oxidative stress. The sequential treatment of methyl jasmonate (MJ) plus methyl-beta-cyclodextrin (CD) and cadmium (Cd), namely the (MJ + CD)_Cd strategy, exhibited the highest ferric reducing antioxidant power (FRAP) with 10.68 +/- 0.17 mg ascorbic acid/g hairy root dry weight, the highest O-2(center dot-)-scavenging capacity with an IC50 value of 0.89 +/- 0.45 mu g/mL and the highest H2O2-scavenging ability with an IC50 value of 133.90 +/- 11.96 mu g/mL, which showed a significant increase from the untreated control group. A potent DNA nicking assay was used to investigate the antioxidant and pro-oxidant activity of crude extracts. Low concentrations (25 mu g/mL) of crude-elicited hairy root extract exhibited DNA-protective activity against free radical-mediated DNA damage, whereas higher concentrations (75 and 125 mu g/mL) exhibited pro-oxidant activity in the Fenton reaction. In addition, a crude extract concentration of 50 mu g/mL could directly cause DNA damage in the non-Fenton reaction. Based on the evidence that elicited bioactive compounds induced both antioxidant and pro-oxidant activity in a concentration-dependent manner, the hairy root extracts would be considered as health-beneficial compounds and can be further applied as health-promoting or cancer chemotherapeutic agents.

Automated summary

Pre-treatment with methyl jasmonate and methyl-beta-cyclodextrin followed by cadmium induced the highest ferric reducing antioxidant power in peanut hairy root culture. Crude extracts showed DNA-protective activity at low concentrations, but exhibited pro-oxidant activity at higher concentrations. The bioactive compounds in hairy root extracts have the potential to serve as health-promoting or cancer chemotherapeutic agents, with both antioxidant and pro-oxidant activities in a concentration-dependent manner.