An electrochemical impedance sensor for monitoring of gallic acid inhibited neuraminidase activity of PPR HN protein

Abstract

Peste des petits ruminants (PPR) virus has a surface glycoprotein, hemagglutinin neuraminidase (HN) with functional sites for cell attachment and neuraminidase (NA) activity. The neuraminidase activity of PPR virus (Sungri/96) was biochemically characterized with fluorometric assay, enzyme linked lectin assay (ELLA) and electrochemical impedance spectroscopy (EIS). Furthermore, the inhibitory effect of gallic acid on the virus neuraminidase activity was also evaluated in-vitro in B95a cells. Screen printed carbon electrode were used for the EIS assay. The activity of the viral neuraminidase was presented as the change in charge transfer resistance (Rct). The measurement of neuraminidase activity with EIS was found comparable to ELLA. Cell toxicity (CC50) concentration of gallic acid was found to be 61.0 ± 1.0 µM in B95a cells. A dose dependent effect of gallic acid on the virus neuraminidase activity was observed in both EIS and ELLA measurement. The anti PPRV activity of gallic acid was quantified by cell ELISA and 7.0 ± 1.0 µM was calculated concentration that has 50% viral inhibition in B95a cells. The gallic acid used in present study had neuraminidase inhibitory activity both in ELLA and EIS, furthermore it also reduces the virus propagation in vitro in B95a cells. For high throughput screening of anti-neuraminidase compounds including phytocompounds, electrochemical impedance spectroscopy could be vividly used.