Placental infection by the Zika Virus: investigation of the action of natural products
with antiviral activity
Natural products, ZIKV, Passiflora edulis, Schinus terebinthifolius Radd
Introduction: The Zika virus (ZIKV) is an emerging arbovirus, which has spread
rapidly in recent years and has caused large outbreaks. It is originally from Africa and
has spread to Asia, Oceania and the Americas, and its main transmitter is the genus
Aedes mosquito. In 2015, in the face of an outbreak in Brazil, it drew the attention
of health authorities, where the association of the virus infection with fetal
neurological complications began, supported by studies carried out during the ZIKV
outbreaks in Brazil and French Polynesia. Although ZIKV activity has declined
significantly in recent years, the potential for ZIKV introduction and transmission in
new areas is high and unpredictable. Thus, the development of vaccines and drugs
against ZIKV remains a research priority, with natural products being important
sources in the discovery of compounds with antiviral activity. Objective: To
characterize the antiviral effect of ethanol extracts obtained from the species
Passiflora edulis, Schinus terebinthifolius Raddi, Moringa oleífera and Cocos lucífera,
on the response of placental cells exposed to ZIKV. Methods: HTR-8/SVneo cells
derived from the first trimester of pregnancy and term placental explants were
exposed to the extracts and cell viability was evaluated. The extracts that proved to
be viable were exposed to infection by the ZIKV strains in the trophoblast cells and
the antiviral potential was analyzed by qRT-PCR and flow cytometry. In view of the
infection and the treatments of the extracts, the cell cycle and production of
cytokines were analyzed. Results: None of the extracts tested decreased the viability
of placental explants, on the other hand, only extracts of Passiflora edulis seed,
Schinus terebinthifolius Raddi fruit and Schinus terebinthifolius Raddi bark did not
decrease the viability of HTR-8SV/neo cells. All the extracts tested were effective in
reducing the viral load both in HTR-8SV/neo cells and in placental explants, with
more impressive results with the Passiflora edulis seed extract. In the production of
cytokines, none of the extracts intervened in the modulation of interferons.
Infection-induced IL-8 was reduced by the bark extract of Schinus terebinthifolius
Raddi, while IL-10 was increased with the fruit extract of Schinus terebinthifolius
Raddi. TNF-a was decreased in the presence of treatments with Schinus
terebinthifolius Raddi and Passiflora edulis. Conclusion: All these results show that
the tested extracts are promising sources of compounds with antiviral action against
ZIKV, mainly from Schinus terebinthifolius Raddi and Passiflora edulis.