ADRB2 and Respiratory tract infection: As mentioned above, MXSG is used to treat respiratory tract infections, acute bronchitis, pneumonia, bronchial asthma and other lung diseases, as well as H1N1, Corona Virus Disease 2019 (COVID-19) and other pulmonary infectious diseases (Wang et al., 2011), with mechanism of stimulation of beta 2-adrenergic receptors on bronchial smooth muscle, inhibition of neutrophil entry into the airways, and reduction of airway inflammation (Kao et al., 2001), and exerts broad-spectrum antiviral effects by inhibiting viral RNA and protein synthesis (Hsieh et al., 2012).