Chemical Constituents, Quantitative Analysis, Anti-SARS-CoV-2 and Antioxidant Activities of Herbal Formula “Ping An Fang Yu Yin”

COVID-19 is a global pandemic infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The herbal formula, Ping An Fang Yu Yin (PAFYY), has been used to prevent respiratory viral infections for many years. This study aims to evaluate the effect of PAFYY on SARS-CoV-2 infection, oxidative stress, and inflammation via in vitro, investigate the chemical composition by full constituent quantitative analysis, and verify its anti-viral potential against SARS-CoV-2 using in silico. In this study, a total of eleven compounds, twenty amino acids, saccharide compositions, and trace elements were found and quantitatively determined by chromatographic techniques. PAFYY displayed free radical scavenging activity (DPPH, SC50: 1.24 ± 0.09 mg/mL), SOD activity (68.71 ± 1.28%), inhibition of lipoxygenase activity (75.96 ± 7.64 mg/mL) and interfered the interaction of SARS-CoV-2 spike protein and angiotensin-converting enzyme 2 (48.04 ± 3.18%). Furthermore, in-silico analysis results supported that liquiritin, 3,5-dicaffeoylquinic acid, and luteolin-7-O-glucoside with the highest affinity between SARS-CoV-2 RBD and human angiotensin-converting enzyme II (hACE2) receptor. Our findings suggest that PAFYY has the potential for anti-SARS-CoV-2 infection, anti-oxidation stress, and anti-inflammation, and may be used as supplements for amelioration or prevention of COVID-19 symptoms, as well as the representative compounds can be used for quality control of PAFYY in the future.