Antiviral Activity of Rapana thomasiana Hemocyanin against Bovine Rotavirus

The aim of this study was to investigate the antiviral activity of hemocyanin isolated from natural marine snail Rapana thomasiana (RtH) and its structural subunit RtH-1 against Bovine rotavirus (BRV). R. thomasiana is widespread in the Black Sea, Mediterranean Sea and Marmara Sea, and hemocy¬anins have received extensive research in recent years due to their antitumor, antibacterial, antiviral and antifungal activities. We examined RtH from R. thomasiana and its subunit (RtH-1) for its effect on the replication of Bovine rotavirus (BRV), Negovan strain, in Madin-Darby bovine kidney (MDBK) cells. The experiments were performed at non-toxic concentrations of both products - lower than the maximum tolera¬ble concentration (MTC) (10 mg/mL). The anti-BRV activity of RtH and RtH-1 was determined in two time intervals - at 48 hours and 120 hours of exposure. At 48 hours, the activity of both products was significant, showing dependence on the concentration of the applied substance. In RtH-1 the most noticeable decrease in viral titer with Δlg = 2.25 was observed at concentrations higher than 1 mg/mL, and in RtH the same effect was observed at a concentration of 3.2 mg/mL. In the second time interval (120 hours), the activity of both products decreased significantly. It could be concluded that conformational changes in proteins are the most likely reason for the clear antiviral activity at 48 hours, followed by a decrease in activity as time progresses to 120 hours. On the other hand, virus molecules can also undergo conformational changes over time.