|
Evaluation of aqueous
methanolic extract of Sorghum bicolor leaf base for
antinociceptive and anti-inflammatory activities
F. C. Nwinyi* and H. O. Kwanashie
Department
of Pharmacology and Clinical Pharmacy, Ahmadu Bello
University Main Campus, P. M. B. 1045, Zaria, 810271, Kaduna
State, Nigeria.
*Corresponding author. E-mail:
fchyme@yahoo.co.uk.
Tel: +234-802 321 5755.
Accepted 5
June, 2009 |
|
Sorghum
bicolor
(Family: Gramineae; Poaceae) is used traditionally for some
ailments related to pain and inflammation. This study
was therefore aimed at investigating possible
antinociceptive and anti-inflammatory effects of this plant.
The aqueous methanolic (70% methanol ) extract of the leaf
base, its aqueous and ethylacetate fractions were evaluated
for antinociceptive activity using acetic acid-induced
writhing test (test on chemical pain) and tail flick test
(test on mechanical pain) in Swiss albino mice. The site for
antinociception was determined using formalin test in Wistar
rats. Anti-inflammatory activity was evaluated using egg
albumin-induced hind paw oedema in Wistar rats. Acute
toxicity studies of all the extracts were also carried out
on rats and mice to determine their LD50. The
aqueous methanolic extract and its aqueous fraction
exhibited a significant (P < 0.05) antinociceptive activity
while the ethylacetate fraction did not show antinociceptive
effect. The aqueous methanolic extract showed higher percent
pain inhibition in the early phase of formalin test but did
not inhibit inflammation. The calculated oral LD 50
value for the aqueous methanolic extract was ≥ 2000 mg/kg in
both mice and rats. In rats, the calculated intraperitoneal
LD 50 value 48 h post treatment observation was
1,414.2 mg/kg while in mice, the calculated intraperitoneal
LD 50 value was 1341.6 mg/kg for 48 h post
treatment time. The intraperitoneal LD50 value
for both aqueous and ethylacetate fractions were ≥ 2000
mg/kg 48 h post treatment. The study revealed that S.
bicolor leaf base contains analgesic components which
are probably more in the aqueous fraction of the crude
extract. This effect appeared centrally mediated. The
extract did not show anti-inflammatory property.
Key
words: Sorghum bicolor, fractions, antinociception, anti-inflammation, acute toxicity. |
