Discussion:
During the 1800's, patients were treated with
S. purpurea after the symptoms for smallpox had already appeared and as a preventive during epidemics. Historical reports stated that
“the effects were so…speedy and beneficial as to leave no doubt that they were due to the Sarracenia” [8].
“The disease continued very severe until (S. purpurea) was administered, and became entirely changed in its severity after the administration…, the effect being due to (S. purpurea) alone” [1]. In this study, we demonstrated that
S. purpurea extracts were able to effectively inhibit viral replication and the viral-induced cytopathic effects of various
Orthopoxviruses. The data supports that
S. purpurea effectively inhibited MPXV and VARV replication similarly to VACV, and points to the relevance of using VACV as a model of the more virulent MPXV and VARV. At doses where virus replication was inhibited, little to no cellular toxicity was observed.
In regards to broad-spectrum antiviral activity, the data supports that the antiviral activity associated with
S. purpurea was at least partially specific to poxviruses in comparison to other non-related viruses tested. Since
S. purpurea treated cells were still able to support the replication of other virus families, it further supports that
S. purpurea treatment does not disrupt the intracellular environment of the cell. For VACV, a single treatment was fairly effective at preventing viral replication, but partial replication soon recovered,
likely due to a breakdown or utilization of the active component(s) within the extract. However, treating the cells with fresh S. purpurea every six hours completely abolished the replication of VACV. This correlates well with how patients were treated in the past where the treatment regime involved taking 4–6 doses of the extract per day
[11]. Our data supports that extracts of
S. purpurea effectively inhibit the replication of VACV, MPXV and VARV
in vitro. This activity toward
Orthopoxviruses is consistent with the historical reports of
S. purpurea as a therapy against smallpox infections. The goal of this study was to characterize anti-poxvirus activity of
S. purpurea extracts in order to verify and evaluate the botanical material under similar preparation methods as that done historically in the 1800's. Collectively,
the data suggests that S. purpurea targets early viral transcription leading to an inhibition in viral replication.