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

Resumo

Introduction: Guatteria australis belongs to the Annonaceae family and is
considered a native and endemic species in Brazil. The analysis of the essential oil
of G. australis presented in vitro antimicrobial and antiproliferative activity against
the tumor cell lines and anti-inflammatory in vivo in pleurisy model. Other analyzes
such as the biomonitoring phytochemical study of bioactive methanolic extracts
allowed to isolate and identify four substances of G. australis, being palmatine,
lysicamine, subsessiline and liriodenine (SIQUEIRA, C.A.T. 2015). This study aimed to
evaluate the extract of G. australis branches on mechanical and thermal
hyperalgesia induced by inflammation. Material and Methods: Three
experimental groups of male Swiss mice (n = 6) were formed, and the control group
was treated with 0.9% saline solution, one group treated with the ethanolic extract
of G. australis and another with dexamethasone (1 mg / kg). They were induced to
edema with injected carrageenan (300 ?g). The mechanical hyperalgesia was
evaluated by the electronic von Frey test and the cold allodynia with the acetone
drop test. Both were evaluated three and four hours after induction of inflammation.
Results: The results of the paw with draw Threshold test compared to the control
group, the group treated with the extract of G. australis reversed the mechanical
hyperalgesia in the 3 hour period by 93% and the 4 hour period by 80%. In the cold
allodynia test when compared to the control group and the dexamethasone group,
the group treated with the extract of G. australis reverted 35% to cold allodynia in
relation to the control group and the dexamethasone group reverted 61% in relation
to the group control group, both within 3 hours and 4 hours, the dexamethasone
group reversed 51%. Discussion and Conclusion: In summary, the G. australis
extract presented potential action on mechanical and thermal hyperalgesia induced
by inflammation and new studies should be performed to show its mechanisms of
action.
INTRODUCTION
Guatteria australis belongs to the Annonaceae family and is considered a
native and endemic species in Brazil and its popular names are pindaúva-preta,
cork, embiú, imbiú, pindaúva-branca. Its main phytogeographic domain is the
Atlantic Forest, in the Dense Ombrophylous Forest, but it is found in the Northeast
(Bahia), Center-West (Goiás), Southeast (Minas Gerais, Espírito Santo, São Paulo and
Rio de Janeiro), South , Santa Catarina and Rio Grande do Sul) (LOBÃO, AQ et al.,
2011). The analysis of the essential oil of G. australis presented in vitro
antimicrobial and antiproliferative activity against the tumor cell lines and antiinflammatory
in vivo in pleurisy model. Other analyzes such as the biomonitoring
phytochemical study of bioactive methanolic extracts allowed to isolate and identify
four substances of G. australis, being palmatine, lysicamine, subsessiline and
liriodenine (SIQUEIRA, C.A.T. 2015). Hyperalgesia is the increase in the pain
response produced by a noxious stimulus and according to the modifications can be
classified as primary hyperalgesia, being restricted to the injured site and is
observed with mechanical and thermal stimuli and generally lasts for hours up to
four days after the surgical incision; and in secondary hyperalgesia that occurs in
the area surrounding the lesion, occurs with mechanical stimuli and frequently lasts
for hours up to seven days after tissue injury and according to the size of the area of
secondary hyperalgesia, there is a greater chance of developing persistent pain
after surgery (OLIVEIRA, CMB et al., 2010). Inflammation is characterized as a
complex reaction of vascularized tissues to infection, exposure to toxins or cellular
injury, with extravasation of plasma proteins and leukocytes. Although inflammation
plays a protective role in the control of infections, it can also cause tissue damage
(ABBAS, A.K. et al., 2008). This study aimed to evaluate the extract of G. australis
branches on mechanical and thermal hyperalgesia induced by inflammation.
MATERIAL AND METHODS
Swiss mice were divided in three groups (n=6), one group received the saline
(0.9%) by oral route, one group treated with ethanolic extract from G. australis and
another treated subcutaneously with dexamethasone ( 1 mg / kg). Each animal
received 100 ?L of carrageenan (300 ?g) injected intradermally into the right hind
paw one hour after the treatments, inducing edema. Mechanical hyperalgesia was
evaluated using the electronic von Frey test, increasing pressure method and cold
allodynia with the acetone drop test. Both experiments were evaluated three and
four hours after induction of inflammation. The experimental procedures performed
in this study were in agreement with the Ethical Directors in Animal Research and
approved by the Ethics Committee on Animal Experimentation at UFGD (01/2015).
RESULTS
The study carried out the following comparative results between the control
group, when compared in two different methods: The first was the Paw with draw
Threshold methodology. In this first comparison it was obtained that the G. australis
reversed mechanical hyperalgesia in 94% compared to the control group, occurring
in two periods, one of 3 hours and another of 4 hours. In the latter, the reduction
was 80%. In a second moment the following procedure was used: Cold Alodynia -
"Cold Allodynia". The following result was obtained when compared to the control
group and to the drug Dexamethasone: G. australis reverted 35% to cold allodynia
compared to the control group. Dexamethasone reversed 61% of cold allodynia
compared to the control group. The comparative described refers to the first 3
hours, with a reversal of 51% by Dexamethasone in the 4 hour of the experiment.
DISCUSSION AND CONCLUSION
In summary, the G. australis extract presented potential action on
mechanical and thermal hyperalgesia induced by inflammation and new studies
should be performed to show its mechanisms of action.
Acknowlegments
The authors thank the Drª. Cândida Kassuya for all the knowledge acquired
during the study and Prof. Dr. Marcos José Saulo for the partnership with the
research group.