Urolithin A, a gut metabolite produced from foods containing ellagic acid, like walnuts, berries, and pomegranates, had a protective role in PD by markedly strengthening mitochondrial biogenesis via the SIRT1/PGC-1α pathway and ameliorating 6-OHDA-induced mitochondrial dysfunction [317]. The gene discussed is SIRT1; the disease is Parkinson disease.