Background
Plant species from the genus
Tecoma
are found in tropical and subtropical regions around the world. Some of them are grown as ornamental plants and others can be used as medicinal plants. In the present study, ethanolic extracts from trunks and leaves of
Tecoma
species were tested in vitro using assays against the
Zika virus.
Methods
There was a total of 8 extracts obtained from different anatomical parts of three
Tecoma
species. The
Tecoma castaneifolia
,
T. garrocha
,
T. stans
var.
angustata
and
T. stans
var.
stans
were prepared by percolation with ethanol. The antiviral activity was assayed in vitro against the
Zika virus
by the MTT colorimetric method (
n
= 3). The UPLC-DAD-MS analysis of ethanolic extracts was performed from all the studied species. The biofractionation of
T. stans
var.
stans
trunk extract using different separation techniques led to the isolation of crenatoside compound.
Results
Ethanolic extract from
Tecoma
species leaves were more active against the
Zika virus
(EC
50
149.90 to 61.25 μg/mL) when compared to the trunk extracts tested (EC
50
131.0 to 66.79 μg/mL and two were not active). The ethyl acetate and aqueous fractions obtained from
T. stans
var.
stans
trunk were active against the
Zika virus
with EC
50
values of 149.90 and 78.98 μg/mL, respectively. Crenatoside is a phenylethanoid glycoside isolated from the ethyl acetate of
T. stans
var.
stans
trunk extract. This compound was tested and exhibited EC
50
34.78 μM (21.64 μg/mL), thus demonstrating a better result than the original ethanolic extracts as well as others extracts of
Tecoma
species, and it was more active than the positive control, ribavirin (386.84 μM). Furthermore, its selectivity index was at least 2.5 times higher than the tested ethanolic extracts and 11.1 times more potent than ribavirin.
Conclusion
The
Tecoma
species demonstrated interesting in vitro activity against the
Zika virus
. The crenatoside, phenylethanoid glycoside that was for the first time isolated from
Tecoma stans
var.
stans
, exhibited a potent and relevant anti-
Zika virus
activity, being more active than ribavirin (positive ...