GSR and infection: However, addition of Riboflavin along with antibiotics AZM or CIP to the peritoneal macrophages followed by infection with S. aureus led to significant increase (p < 0.05) in the activity of glutathione reductase enzyme in the lysate at 60 and 90 min of CIP treated macrophages and only in 90 mins in the AZM treated group when compared to the activity of glutathione reductase enzyme of Riboflavin treated S. aureus infected macrophages (Table 3).