EVALUATION OF Guatteria australis LEAVES ON MECHANICAL AND THERMIC HYPERALGESIA INDUCED BY INFLAMMATION

Resumo

Introduction: : The Annonaceae is the principal magnoliídeas family, with 2440
species and 130 genus (Couvreur et al., 2011; KoekNoorman et al., 1997). In Brazil,
385 species are found, 158 are being endemics, most of the Amazon biome (Maas
et al., 2010). The specie Guatteriaaustralis belong to Annonaceae family and is
widely distributed in Atlantic Forest.Some studies show that species of the genus
Guatteria has a relevant importance therapeutic. However, few studies get to prove
the effectivity of some species.Objective:This study aimed to evaluate the
antinociceptive effect of leaves from G.autralisin mechanical hyperalgesia, as well
thermalallodynia, induced by inflammation. Material and Methods:Three
experimental groups of male swiss mice (n = 6) were formed, a control group that
received only the saline solution 0,9% by oral route, one group treated with the
ethanolic extract from Guatteriaaustralis leaves and another treated by
subcutaneous route with dexamethasone (1mg/kg). Each animalreceived100 ?L of
carragenin (300 ?g) intradermally injected in theirhind right paw one hour after the
treatments inducing edema (Winter et al., 1962). The mechanical hyperalgesia was
evaluated using the increasing electronic pressure-meter test of von Frey
(Vivancoset al., 2004) and the cold allodynia with the acetone drop test (Decosterd
and Woolf, 2000). Both experiments were evaluated three and four hours after the
inflammation induction. The experimental procedures executed in this study were in
accordance with the Ethical Principals in Animal Research and approved by the
Committee for Ethics in Animal Experimentation at the UFGD. Results: In the
hyperalgia mechanic test, the swiss mice group which received the ethanolic
extracts treatment of G. australis reversed significativement in 82% the mechanic
hyperalgia compared to the control group, after three hours of the injection of
100uL of carrageenan on the mice hind right paw. After four hours of inflammation
induction, the group treated by G. australis reverted in 71% compared to the
controlled group. In the second test performed, allodynia to the cold temperature,
showed that the swiss mice group that received the ethanolic extracts treatment
from the leaves of G. australis reverted significativement in 46% the allodynia to
cold temperature compared to the control group, after three hours since the drop of
acetone test beginning. After four hours, the test was performed again and they
checked that the swiss mice group treated with G. australis reverted
significativement in 37% the allodyna to the cold temperature compared with the
control group. Conclusion: In both tests performed, the ethanol extract was
effective compared to the control groups and the group treated with
dexamethasone. After induction of inflammation, the mechanic hyperalgesia was
considerably reversed, as well as the allodynia to the cold temperature after the
acetone test.Taking these results, it can be concluded that the use of the ethanolic
extract of Guatteriaaustralis has benefits over to the sensibility decrease
nociceptive and also the decrease to the allodynia to the cold temperature. Other
studies should be conducted to evaluate the mechanisms of action.
Acknowlegments: CAPES, CNPq and FUNDECT.