NiO nanoparticles induce cytotoxicity mediated through ROS generation and impairing the antioxidant defense in the human lung epithelial cells (A549): Preventive effect of Pistacia lentiscus essential oil

Abstract

Nickel oxide nanoparticles (NiO NPs) have attracted increasing attention owing to potential capacity to penetrate to several human cell systems and exert a toxic effect. Elsewhere, the use of medicinal plants today is the form of the most widespread medicine worldwide. Utilizing aromatic plants as interesting source of phytochemicals constitute one of the largest scientific concerns. Thus this study was focused to investigate antioxidant and cytoprotective effects of essential oil of a Mediterranean plant P. lentiscus (PLEO) on NiO NPs induced cytotoxicity and oxidative stress in human lung epithelial cells (A549). The obtained results showed that cell viability was reduced by NiO NPs, who's also found to induce oxidative stress in dose-dependent manner indicated by induction of reactive oxygen species and reduction of antioxidant enzymes activities. Our results also demonstrated that PLEO contains high amounts in terpinen-4-ol (11.49%), germacrene D (8.64%), α-pinene (5.97%), sabinene (5.19%), caryophyllene (5.10%) and δ-Cadinene (4.86%). PLEO exhibited a potent antioxidant capacity by cell viability improving, ROS scavenging and enhancing the endogenous antioxidant system against NiO NPs in this model of cells. The present work demonstrated, for the first time, the protective activity of PLEO against cell oxidative damage induced by NiO NPs. It was suggested that this plant essential oil could be use as a cells protector.

Keywords: Cytotoxicity; Essential oil; Nickel oxide nanoparticles; Oxidative stress; Pistacia lentiscus.

Graphical abstract

Fig. 1

Characterization of NiO NPs. (A) X-ray diffraction pattern, (B and C) transmission electron microscopy image in deionized water (50, 20 nm) and in full DMEM (200, 50 nm), respectively and (D) frequency of size distribution.

Fig. 2

(A) NiO NPs induced cytotoxicity in A549 cells. Cells were exposed to different concentrations of NiO NPs for 24 h. (B) Effects of PLEO on cell viability. A549 cells were treated with different concentrations of essential oil samples for 24 h also. Triton was used as a negative control. Data represented are mean ± SD of three independent experiments. *p < 0.05; **p < 0.01; ***p < 0.001 treatments compared to control.

Fig. 3

Protective effect of PLEO on NiO NPs induced cytotoxicity. A549 cells were treated with different concentrations of essential oil for 24 h followed by NiO NPs for 24 h. Triton was used as a negative control. Data represented are mean ± SD of three independent experiments. ***p < 0.001 treatments compared to control; ≠p < 0.05; #p < 0.01; ^##p < 0.001 compared to NiO NPs.

Fig. 4

(A) Effects of NiO NPs and PLEO on ROS production in A549 cells. Cells were treated with different concentrations for 24 h. H₂O₂ was used as a negative control. (B) PLEO attenuates NiO NPs induced ROS generation. A549 cells were treated with different concentrations of essential oils for 24 h followed by NiO NPs for 24 h also. Data represented are mean ± SD of three independent experiments. *p < 0.05; ***p < 0.001 treatments compared to control; ≠p < 0.05 compared to NiO NPs.

Fig. 5

Intracellular ROS generation in A549 cells. Images were captured with a fluorescence microscope (OLYMPUS IX73). Effects of NiO NPs (A) and PLEO (B) on ROS production. Cells were treated with different concentrations for 24 h. (C) PLEO attenuate NiO NPs induced ROS generation in dose-dependent manner. A549 cells were treated with different concentrations of essential oil for 24 h followed by NiO NPs for 24 h also.

Fig. 6

(A) Effects of NiO NPs and PLEO on SOD activity in A549 cells. Cells were treated with different concentrations for 24 h. H₂O₂ was used as a negative control. (B) P. lentiscus essential oil attenuates NiO NPs decreased SOD activity. A549 cells were treated with different concentrations of essential oils for 24 h followed by NiO NPs for 24 h also. Data represented are mean ± SD of three independent experiments. **p < 0.01 treatments compared to control; ≠p < 0.05 and #p < 0.01compared to NiO.

Fig. 7

(A) Effects of NiO NPs and PLEO on CAT activity in A549 cells. Cells were treated with different concentrations for 24 h. H₂O₂ was used as a negative control. (B) PLEO attenuates NiO NPs decreased CAT activity. A549 cells were treated with different concentrations of essential oils for 24 h followed by NiO NPs for 24 h also. Data represented are mean ± SD of three independent experiments. *p < 0.05 treatments compared to control; ≠p < 0.05 compared to NiO NPs.