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Glycyrrhiza glabra (licorice) reduced neuropathic pain perception by reducing cortisol, brain nitric oxide and brain lactic dehydrogenase levels in experimental animals

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S44 Abstract / IBRO Reports 7 (2019) S2–S51
significantly (p< 0.05) increased the number of sectional cross-
ings in OFT. At this dose, CG significantly (p< 0.05) reduced the
duration of immobility in FST on day 1 and 7, with significant
increase (p< 0.05) in the brain level of adrenaline relative to con-
trol. The standard antidepressant drug used, fluoxetine (selective
serotonin reuptake inhibitor), significantly reduced (p< 0.05) the
duration of immobility in the FST (day 1) and TST (day 7 and 21)
relative to control. It significantly increased (p< 0.05) the duration
of swimming on day 1 in FST compared with control. Histopatho-
logical assessment of representative brain tissues showed normal
histological presentations in all the treatment groups.CG exhib-
ited antioxidant activity in the metal chelating, DPPH and FRAP
in-vitro assays. In respect of the acute toxicity test, CG did not
produce any mortality administered orally up to 5 g/kg. No visi-
ble signs of delayed toxicity and mortality were observed when
the animals were monitored for a further 14 days. In respect of the
intraperitoneal (i.p.) route, no deaths were recorded at the low-
est dose of 500 mg/kg while mortality was 100 % at the highest
dose of 1500 mg/kg. The i.p. median lethal dose (LD50) was esti-
mated to be 1288.25 mg/kg. Qualitative phytochemical screening
revealed the presence of alkaloids, phenols, flavonoids, glycosides,
reducing sugars, tannins, phlobatannins, saponins, steroids and ter-
penoids. Quantitative phytochemical estimation revealed the order
of abundance to be flavonoids >tannins >alkaloids >glycosides >
saponins >reducing sugars. In conclusion, sub-acute treatment
with CGresulted in significant antidepressant activity possibly
associated with adrenergic enhancement in the brain. Also, CG pos-
sesses in-vitro antioxidant activity probably due to the presence of
polyphenols. The results justify the ethnobotanical use of CG for the
management of mental disorder.
Keywords:Crinum glaucum, Forced swim test, Tail suspension
test, Antidepressant, Antioxidant.
Ethical approval: CMUL/HREC/12/17/330 (Health Research
Ethics Committee, College of Medicine, University of Lagos,
Nigeria).
https://doi.org/10.1016/j.ibror.2019.09.088
E7
Glycyrrhiza glabra (licorice) reduced
neuropathic pain perception by reducing
cortisol, brain nitric oxide and brain lactic
dehydrogenase levels in experimental animals
O. Akintoye1,, O. Fabunmi 1, O. Olaseinde 2,A.
Ajibare1, G. Ayilara 2, B. Owoyele 2
1Department of Physiology, College of Medicine,
Ekiti State University, P.M.B. 5355, Ado-Ekiti 36001,
Nigeria
2Department of Physiology, College of Health
Sciences, University of Ilorin, P.M.B.1515, Ilorin
240001, Nigeria
E-mail address: akinclass15@gmail.com
(O. Akintoye).
Neuropathic pain is one of the most common causes of chronic
pain worldwide, causing a lot of psychological discomfort “physi-
ologic stress” and physical disability challenges, which translated
to high medical burden on the global economy. There are differ-
ent anti-nociceptive treatments for neuropathic pain with their
limitations. The extract of Licorice root has been used in many
food products, soft drinks and snacks as a sweetener. Several stud-
ies have demonstrated the pharmacological importance of licorice
such as anti-inflammatory, anti-tumor, anti-viral, anti-nociceptive
activity on acute pain and anti-microbial activities among others.
However, there is no data till date to demonstrate its effect on
neuropathic pain. Therefore, the aim of the study is to study the
effect of licorice root extract on sciatic nerve induced neuropathic
pain. Thirty-five male 6 week-old Wistar rats bought at the Ani-
mal House of College of Medicine, Ekiti State University, (weight
200 ±20 g) were used for the study. The rats were housed and main-
tained in standard conditions of light, feeding and temperature in
the Animal House of College of Medicine, Ekiti State University.
The study was conducted in accordance with the standards estab-
lished by the Guide for the Care and Use of Laboratory Animals.
Baseline values for von Frey test were obtained prior to surgery.
Neuropathic pain was induced by chronic constriction injury (CCI)
of sciatic nerve of rats in groups 2 to 7. Group 1 did not undergo
CCI. Groups 1 and 2 received no interventions. Administrations of
licorice began in group 3, 4 and 5 three days after surgery and
continued for 18 days. Group 3 received 10 mg/kg of Imipramine;
4 and 5 received 75 mg/kg and 150 mg/kg of licorice respectively.
Group 6 and 7 received 75 and 150 mg/kg respectively for 10 days
before surgery and treatment continued three days after surgery for
another 18 days. All vehicle and licorice were administered paren-
terally. Paw withdrawal thresholds were assessed on days 3, 7, 14
and 21. Blood plasma levels of cortisol, brain lactate dehydrogenase
(LDH) and brain nitric oxide (BNO) were screened using ELISA on
day 21. Groups treated with licorice and imipramine demonstrated
significant increase in change in paw withdrawal threshold com-
pared with group 2 that received no intervention. Cortisol, brain
LDH and BNO concentrations were significantly lower (p< 0.05) in
groups 5, 6 and 7 compared with group 2 and 3 rats. In conclusion,
licorice exhibits anti-nociceptive property through the suppression
of the central noradrenaline pathway and preventing HPA axis dys-
function in CCI induced neuropathic pain animal. This effect is dose
and duration dependent, opening a new door in the management
of neuropathic pain.
Keywords: Animal; Brain nitric oxide; Cortisol; Licorice; Neu-
ropathic pain.
https://doi.org/10.1016/j.ibror.2019.09.089
E8
Subacute oral administration of codeine causes
up-ward regulation of pro-apoptotic genes in
the forebrain tissue of rabbits
A.A. Abubakar1,, H.S. Garba 1, G.S. Uthman 2
1Department of Human Anatomy, University of
Maiduguri, Maiduguri, Borno State, Nigeria
2Department of Pharmacology and Toxicology,
Faculty of Pharmacy, University of Maiduguri,
Maiduguri, Borno State, Nigeria
E-mail addresses: abubakarasabe97@gmail.com,
garbaus2000@yahoo.co.uk (A.A. Abubakar).
Addictive drugs, such as cocaine, opioidsand amphetamines,
trigger strong and persistent neuroadaptive changes in the brain
through a series of gene regulatory mechanisms leading to addic-
tion. Studies have reported involvement of miRNAs in drug
addiction mainly associated with cocaine-related drug addiction,
although there is no direct report of miRNAs involvement in opioid-
related addiction so far. Apoptosis or programmed cell death is a
normal process of removing candidate cells for death. Accordingly,
this is a physiological process for progression and homeostasis of
human systems such as immune and nervous systems. Previous
investigations have revealed that several endogenous and exoge-
nous agents can induce apoptosis. Among the known regulators of
apoptosis,the Bcl-2 protein stands out for its ability to suppress cell
death induced by a wide variety of insults and stimuli, including
some of the mediators suspected to be inducers of neuronal cell
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