Antioxidant and Cytoprotective Potential of the Essential Oil Pistacia lentiscus var. chia and Its Major Components Myrcene and α-Pinene

The antioxidant, cytoprotective, and wound-healing potential of the essential oil from the resin of Pistacia lentiscus var. chia (mastic oil) was evaluated, along with that of its major components, myrcene and alpha-pinene. Antioxidant potential was monitored as: (i) direct antioxidant activity as assessed by 2,2-di-phenyl-1-picrylhydrazyl (DPPH), 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), and ABTS assays; (ii) DNA damage protection activity; and (iii) cytoprotective activity as assessed via induction of transcription of genes related to the antioxidant response in human keratinocyte cells (HaCaT). The cytoprotective potential of the test substances was further evaluated against ultraviolet radiation B (UVB)- or H2O2-induced oxidative damage, whereas their regenerative capability was accessed by monitoring the wound closure rate in HaCaT. Mastic oil and major components did not show significant direct antioxidant activity, however they increased the mRNA levels of antioxidant response genes, suggesting indirect antioxidant activity. Treatment of HaCaT with the test substances before and after UVB irradiation resulted in increased cell viability in the cases of pre-treatment with mastic oil or post-treatment with myrcene. Increased cytoprotection was also observed in the case of cell treatment with mastic oil or its major components prior to H2O2 exposure. Finally, mastic oil and myrcene demonstrated a favorable dose-dependent effect for cell migration and wound closure. Collectively, mastic essential oil may exert its promising cytoprotective properties through indirect antioxidant mechanisms.

Automated summary

Although mastic oil and its major components did not exhibit significant direct antioxidant activity, they were able to increase mRNA levels of antioxidant response genes, suggesting an indirect antioxidant activity. These substances showed beneficial effects on cell viability and protection against UVB or H2O2-induced oxidative damage, as well as promoting cell migration and wound closure in a dose-dependent manner. Overall, mastic essential oil may exert promising cytoprotective properties through indirect antioxidant mechanisms.