Lime and orange essential oils and d-limonene as a potential COVID-19 inhibitor: Computational, in chemico, and cytotoxicity analysis

The COVID-19 pandemic has substantially impacted the world health systems, causing public health concerns, and the search for new compounds with antiviral activity is of extreme interest. Natural molecules with bioactive potential are a trend, with essential oils (Eos) being the focus of recent studies. Thus, this study evaluates in chemico the d-limonene inhibitory activities in the viral genome of SARS-CoV-2 and analyzes the cytotoxic potential and safety profile of d-limonene and lime and orange EOs with a high content of d-limonene. The EOs were extracted and characterized, and the in chemico computational analysis for the determination as a potential anti-SARS-CoV-2 was performed with d-limonene, the major compound in EOs. The cytotoxicity analysis of EOs and d-limonene was carried out with MRC-5 and HaCaT, and the preliminary safety profile was also evaluated by the HET-CAM assay. d-limonene was suggested as a promising compound for anti-SARS-CoV-2 research, since the molecule does not provide mutagenic and cytotoxic fragments, and does not have irritating potential when diluted, in addition to having favorable pharmacokinetic characteristics, through in chemico analysis. Collectively, the results reveal the antiviral potential of lime and orange EOs, as well as their major compound. In this sense, further studies should be conducted to understand the antiviral mechanisms.