PPARGC1A and COVID-19: The therapeutic potential of thymoquinone, a component of Nigella sativa, against COVID-19 is worthy of further investigation due to multiple evidence of this compound’s efficacy in targeting the AMPK/PPARγ/PGC-1α and Nrf2/heme oxygenase (HO-1) pathway and in preventing SARS-CoV-2 entry into the cells [256,257,258].