STAT3 and viral infectious disease: Curcumin also inhibits several important signalling pathways in viral infection, such as transcription factors (NF-κB, signal transducer and activator of transcription 3 (STAT-3), Vnt/b-catenin, nuclear factor E2-related factor (Nrf2), p38/MAPK, and virus-induced inflammation by modulating the manifestation of various factors (IL-10, Interleukin-18 (IL-18), IL-6, tumour necrosis factor (TNF) α/β and COX-2) in COVID-19 [153,154].