GASTROPROTECTIVE EFFECT OF AQUEOUS STEM BARK EXTRACT OF ANOGEISSUS LEIOCARPUS AGAINST ETHANOL-INDUCED GASTRIC ULCER IN RATS
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Date
2021-03-26
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Ahmadu Bello University Zaria
Abstract
The Gastroprotective effect of aqueous stem bark extract of Anogeissus leiocarpus against
ethanol induced gastric ulcer in albino rats was investigated. Eighty-six albino rats (weighing
160-250g) of both sexes were used in this study. Phytochemical studies revealed the presence of
flavonoids, alkaloids, saponins, anthraquinones, tannins, cardiac glycosides, steroids and
triterpenes. The median lethal dose (LD50) of the aqueous stem bark of A. leiocarpus was found
to be above 5000mg/kg body weight orally. Pre-treatment by oral administration of aqueous
stem bark extract of A. leiocarpus at doses of 100, 200 and 400mg/kg b.w for 14 days, dose
dependently and significantly decreased the mean ulcer score, ulcer index, percentage ulceration
and preventive index (p˂0.05) induced by 70% ethanol. The standard drug (cimetidine
100mg/kg) also decreased the ulcer scores. The severity of the reaction to ethanol on gastric
mucosa and cytoprotection by aqueous A. leiocarpus were apparent by histological assessment of
the gastric mucosa. The ulcer control showed intense ulcerated gastric mucosal epithelial cells,
necrotic tissue and heavy infiltration. The section of gastric mucosa from rat pre-treated with
stem bark aqueous extract of Anogeissus leiocarpus at 100 and 200mg/kg b. w. showed slightly
eroded mucosal epithelial cells, less infilteration and haemorrhage. In the 400mg/kg b.w. stem
bark aqueous extract of Anogeissus leiocarpus pre-treated rat, there is no observable
haemorrhagic necrosis of gastric mucosa and showed protection against the histopathological
changes observed in ulcer (ethanol) treated group with an intact gastric pits, maintenance of
mucosa even after exposure of ethanol. Cimetidine (100mg/kg b.w.) pre-treated group
demonstrates slight ulceration, less hemorrhagic necrosis and infiltration in the gastric mucosa of
rat. The oxidative analysis shows significant decrease in Malondialdehyde (MDA) at 100mg/kg,
200mg and 400mg/kg b.w as well as the (100mg/kg b.w) cimetidine group (p˂0.05) when
compared with the ulcer control activity. Antioxidant capacity of animals treated with 100mg/kg,
200mg/kg and 400mg/kg b.w showed a significant increase in catalase activity as well as
100mg/kg cimetidine group (p˂0.05) when compared with the ulcer control group. There was a
significant increase (p˂0.05) in Superoxide dismutase (SOD), at 400mg/kg b.w and 100mg/kg
cimetidine groups when compared with the ulcer control group. In Glutathione Peroxidase
(GPx), there was a significant increase at 200 and 400mg/kg b.w group (p<0.05) but there was
no significant increase in 100mg/kg groups as well as (100mg/kg) cimetidine group (p 0.05)
when compared with the ulcer control group. The aqueous extract of A. leiocarpus was partially
purified by column chromatography. Eluents with similar Rf values were pooled together into
five fractions using thin layer chromatography (TLC). The qualitative (spectrophotometrically
using DPPH) and quantitative antioxidant activity of the five pooled fractions were determined
to using 1, 1-Diphenyl-2-picrylhydrazyl (DPPH) spray to identify the fraction with highest
activity on a TLC plate, an active spot turned from violet to yellow. Fraction A had higher DPPH
percentage inhibition of (97.95%) and the lowest IC50 (20.88). Fourteen phytocomponents with
known and unknown biological activities in the most active fraction A were characterized using
Gas chromatography-Mass spectrometry (GCMS) and Fourier transformed infrared (FTIR). In
conclusion these findings suggest that aqueous stem bark extract of A. leiocarpus possesses
antioxidant properties and dose-dependent gastroprotection, these justify the ethno medicinal use
of the plant in the treatment and management of gastric ulcer.