In vitro and in vivo investigations on the antiviral activity of a series of mixed-valence rare earth borotungstate heteropoly blues

Abstract

A series of mixed-valence rare earth borotungsto-heteropoly blues, K 15H 2[Ln(BW 9W 2O 39) 2]·28H 2O (Ln(2), Ln = La, Ce, Pr, Nd, Sm, Eu, Gd), have been prepared and characterized by IR, UV, XPS, ESR and electrochemistry. The cytotoxicity and antiviral activity of these rare earth borotungstate heteropoly blues were investigated against influenza A(FluVA) strain (A/H1N1/Jingfang/1/91 and A/H3N2/Jingfang/30/95) and influenza virus B(FluVB) (B/Hufang/1/87) in MDCK cells. The results show that K 15H 2[Pr(BW 9W 2O 39) 2]·28H 2O (Pr(2)) exhibits the highest antiviral activity against FluVA with EC 50 of less than 4.0 μg/ml (A/H1N1/Jingfang/1/91) and 6.0 μg/ml (A/H3N2/Jingfang/30/95), respectively, and has the lowest toxicity with CC 50 of more than 480 μg/ml against MDCK cells. Additionally, both K 15H 2[Pr(BW 9W 2O 39) 2]·28H 2O (Pr(2)) and K 15H 2[Eu(BW 9W 2O 39) 2]·28H 2O (Eu(2)) showed excellent antiviral activities against FluVB by inhibiting FluVB replication at an EC 50 of less than 8.0 μg/ml. Furthermore, investigation on in vivo antiviral activity of Pr(2) against FluVA(FM1) in mice by giving the dosage either orally (p.o.) or intraperitoneally (i.p.), indicates that Pr(2) exhibits higher inhibitory activity than that of positive control, virazole, and that it's more effective when administered by i.p.