The effect of Citrus reticulata peel extract containing hesperidin on inhibition of SARS-CoV-2 infection based on pseudovirus entry assays
Orange (Citrus reticulata Blanco) peel contains a flavonoid glycoside hesperidin (HSD) as the primary component. HSD, upon enzymatic hydrolysis, forms hesperetin (HST) aglycone derivate. These two flavonoids have been predicted to have in-silico affinities for ACE2 and SARS-CoV-2 spike, crucial proteins in SARS-CoV-2 infection mechanisms. However, in vitro antiviral testing of orange peel extract, HSD, and HST has not been reported. This study presents for the first time a pseudovirus entry assay approach to test the anti-SARS-CoV-2 effect of HSD, HST, and orange peel extract prepared by hydrodynamic cavitation (HCV). We used a non-virulent pseudovirus model as an alternative to the original virus to target the entry point and enable research to be conducted outside the BSL-3 facility. Based on HPLC analysis, the test results showed that HCV contained HSD at about 4% w/w. Moreover, HSD 1 and 10 M, HST 10 M, and HCV 1 g/ml showed inhibition of pseudovirus entry in 293/hACE2 cells with percentages inhibition 25.92, 37.40, 27.32, and 38.97 %, respectively. Despite HCV 1 g/ml showing about 6 % lower inhibitory activity than HSD 1 M in pseudovirus entry assay, it holds potential as a supplement or source of raw material for HSD as a SARS-CoV-2 antiviral.