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Antioxidant and cytoprotective potentials of Parmeliaceae lichens and identification of active compounds

Figure 2. Effects of extracts Cb (a), Ps (b) and Ug (c) on the cell viability of SH-SY5Y cells evaluated by MTT assay. Initially,
cells were treated only with the extracts in a range of concentrations from 0.25 to 100 µg/ml (24 h) (graphics on the left) and

certain concentrations were later tested for protection against H2O2 (0.1 mM, 30 min) (graphics on the right). Means ± SD,
*p < 0.05 V s control; # p < 0.05 V s H2O2.

3.3.b. Intracellular ROS production assay themselves remarkable intracellular ROS production when
compared to control cells (data not shown). However,
Figure 3 shows that SH-SY5Y cells exposed to H2O2 pretreatments with the chosen concentrations of the three
presented intracellular ROS levels significantly increased extracts displayed a significant inhibitory activity against
to approximately 20% in comparison to control cells H2O2- induced ROS production within the neuron-like
(100% ROS generation) throughout the experiment. cells.
Moreover, none of the lichen extracts caused by

% Intracellular ROS production 140? Hydrogen?
peroxide?0.1?mM?

130?

Cb?+?hydrogen?
120? peroxide?
# # # ## #
110? ## # ## Ps?+?hydrogen?
peroxide?

100? Ug?+?hydrogen?
peroxide?
90?
Trolox?0.01?mM?+?
80? hydrogen?peroxide?
0?
20? 40? 60? 80? 100? 120?

Time (mins)

Figure 3. Effects of pretreatments with Cb, Ps, Ug and trolox on H2O2- induced ROS generation in SH-
SY5Y cells (concentrations: 0.5 µg/mL for Cb and Ug and 0.25 µg/mL for Ps).. Mean values, # p <
0.05 Vs H2O2, and affects all points below.

3.3.c. Determination of caspase-3 activity elevation, almost to basal levels. However, Ps pretreatment
could not diminish the induced caspase-3 up-regulation.
We evaluated the potential inhibitory activity of lichen With these results, protective effects of Cetrelia braunsiana
extracts on caspase-3 activity by a fluorimetric method. As and Usnea ghattensis extracts might be partially attributed
shown in Figure 4, exposition of SH-SY5Y cells to H2O2 to an inhibition of apoptosis, but not in the case of
resulted in a remarkable increase by over 270 % of Parmotrema saccatilobum.
caspase-3 activity compared to control cells. Pretreatments
with Cb and Ug were able to significantly reverse this

@Real Academia Nacional de Farmacia. Spain 171