PHARMACOGNOSTIC AND BIOLOGICAL EVALUATON OF THE ROOT BARK OF SABA COMORENSIS (BOJ.) PICHON (APOCYNACEAE)
PHARMACOGNOSTIC AND BIOLOGICAL EVALUATON OF THE ROOT BARK OF SABA COMORENSIS (BOJ.) PICHON (APOCYNACEAE)
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Date
2009-02
Authors
UNUAGBE, Attah Francis Alfred
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Abstract
Saba comorensis (Boj) Pichon (Apocynaceae) has been used traditionally in
various parts of Tropical Africa region as an aphrodisiac, for rheumatism, arthritis, liver
disease, jaundice, venereal disease, normal spleen function, as laxative, and purgative.
This study is aimed at establishing the pharmacognostic features of the root bark
as well as testing its biological activity.
Macro-morphological features of Saba comorensis root include faint
longitudinal striations with occasional cracks in the inner surface, slightly rough cork
with well marked small circular ridges almost running uniformly with root hairs; the
young root bark is doubled-quilled while the older one is channelled. Fracture is short
and granular while the fractured surface shows a reddish-brown cork.
Microscopically, the transverse section of the root bark showed the presence of sclereids
containing starch grains, pericyclic fibres, lignified sieve tubes, lignified phloem fibres
(14.4-25.2μm), medullary ray usually biseriate with abundant starch grains (3.6-9.0μm)
and clusters of calcium oxalate crystals (7.2-18.0μm ) in the medullarly rays and
parenchyma. The result of extractive values are: alcohol-soluble extractive (16% w/w ±
0.04), water–soluble extractive (22% w/w ± 0.06), total ash (13.67% w/w ± 0.03), the
acid-insoluble ash (8.89% w/w ± 0.02) and moisture content (8.3% w/w ± 0.01).
Preliminary phytochemical analysis revealed the presence of tannins, saponins,
flavonoids, alkaloids, cardiac glycosides, anthraquinones, steroids, terpenoids,
carbohydrates and proteins while the chemo-microscopy indicated the presence of
cellulose, lignin, starch grains, proteins and fat and oils.
Thin-layer chromatography of the ethanolic extract showed four spots each
using 10% sulphuric acid as spray reagent (heated at 100-105оc) and iodine vapour,
while chloroform extract gave two spots using Dragendorff spray reagent.The root of the plant was also evaluated for the LD50, anti-inflammatory,
analgesic, ulcerogenic assay in animal models and its anti-oxidant properties. The LD50
was found to be above 770mg/kg body weight. The ethanolic extract at 50mg/kg,
100mg/kg and 150mg/kg i.p significantly decreased the number of acetic acid-induced
writhing, but not in a dose dependent manner. At 100mg/kg the effect was 90.6%
inhibition, which is significantly comparable to the standard drug aspirin with 91.2%.
The extract elicited a dose dependent inhibition of both acute and chronic inflammation.
Since results from this study strongly indicate the non-steroidal anti-inflammatory- like
activity of the extract, its ulcerogenic effect was tested on fasted animals. Like most
non-steroidal ant-inflammatory drugs, the extract caused gastric ulceration. The
magnitude of the ulceration is dose dependent. Ulceration was higher for ethanol extract
compared to the chloroform extract. The mean ulcer score of the plant extract at
500mg/kg was less than aspirin at 150 mg/kg. The scavenging activity (antioxidant
properties) of the extracts using stable DPPH free radical showed that the ethanol
extract has a higher antioxidant activity relative to chloroform extract. The
concentration of the extract required to quench 50% of the free radical (ED50) for
ethanol and chloroform extracts were 0.198 and 0.284 respectively.
. The result of the pharmacognostic study could be used in setting some
diagnostic indices for the proper identification and preparation of a monograph on the
root bark of the plant,while the results obtained from the biological evaluation provide
scientific basis for the anti-inflammatory, analgesic, and ulcerative properties of the root
of Saba comorensis.
Description
A THESIS SUBMITTED TO THE POSTGRADUATE SCHOOL
AHMADU BELLO UNIVERSITY IN PARTIAL FULFILLMENT OF THE
REQUIRMENTS FOR THE AWARD
OF MASTER OF SCIENCE IN
PHARMACOGNOSY AND DRUG DEVELOPMENT
DEPARTMENT OF PHARMACOGNOSY AND DRUG DEVELOPMENT,
FACULTY OF PHARMACEUTICAL SCIENCES,
AHMADU BELLO UNIVERSITY,
ZARIA, NIGERIA
Keywords
PHARMACOGNOSTIC,, BIOLOGICAL EVALUATON,, ROOT BARK,, SABA COMORENSIS,, PICHON,, (APOCYNACEAE).