Given that ACE2 is highly expressed in the gut and contributes to the pathophysiology of type 2 diabetes [14,15,16], and co-expression of TMPRSS2 with ACE2 is implicated in the pathophysiology of COVID-19 [24,25,26], we also examined the effects of glucose, inflammation and phytochemicals on TMPRSS2. Here, ACE2 is linked to type 2 diabetes mellitus.