Anti-poliovirus activity of Baccharis dracunculifolia and propolis by cell viability determination and real-time PCR

Aims:  The aim of this work was to evaluate the antiviral activities of Baccharis dracunculifolia (extract and essential oil), propolis and some isolated compounds (caffeic and cinnamic acids) against poliovirus type 1 (PV1) replication in HEp-2 cells.
Method:  Three different protocols (pre-, simultaneous and post-treatments) were used to verify the effect of addition time of the variables on PV1 replication by crystal violet method and relative viral RNA quantification by real-time PCR for analysing in which step of virus replication the variables could interfere.
Conclusions:  Data revealed that the B. dracunculifolia showed the best antiviral activity percentage in the simultaneous treatment, as well as lower relative viral quantification by real-time PCR. Variables might block partially the viral entry within cells, affect the steps of viral cycle replication into cells, or lead to RNA degradation before the virus entry into cells or after their release to the supernatant.
Significance and Impact of the Study:  Baccharis dracunculifolia is the most important botanical source of the south-eastern Brazilian propolis, and its potential for the development of new phytotherapeutic medicines has been investigated. Propolis is commonly used for its antimicrobial and immunomodulatory activities. Nevertheless, B. dracunculifolia and propolis effects on PV1 have not been investigated yet.