EVALUATION OF THE ANTIOXIDANT, ANTI-INFLAMMATORY, HEPATOPROTECTIVE AND CYTOTOXIC PROPERTIES OF MORINDA LUCIDA Benth
EVALUATION OF THE ANTIOXIDANT, ANTI-INFLAMMATORY, HEPATOPROTECTIVE AND CYTOTOXIC PROPERTIES OF MORINDA LUCIDA Benth
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Date
2012-11
Authors
ADEJO, GODWIN OJOCHOGU
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Abstract
The anti-oxidant, anti-inflammatory, hepatoprotective and cytotoxic effects of different plant parts of Morinda lucida were studied. Methanolic extracts of the plant parts, viz: the whole fruit, leaf, stem bark, and root were prepared and the yields varied in the order: stem bark > fruit > leaf > root. LD50 test in rats indicated non-toxicity of all the plant parts at doses of 5000mg extract/kg body weight. Anti-oxidation assays presented a higher activity of superoxide dismutase (SOD) among the group post-treated with bark extract. In the pretreatment (hepatoprotective) experiment, there was a significantly higher SOD activity (p<0.05) in the leaf and bark groups than the ‘CCl4 only’ group, indicating antioxidative
effects. However, the vitamins (α-Tocopherol and ascorbic acid) groups showed significantly higher values (p<0.05) than the entire experimental groups. Glutathione peroxidase (GPx) activity was significantly higher in the bark and leaf extracts post-treatment group than the
‘CCl4 only’ group (p<0.05). The extract pre-treatment group also showed the bark and leaf presenting significantly higher activity than the ‘CCl4 only’ group. Catalase enzyme activity
was significantly higher (p<0.05) in the leaf extract pre-treatment group. Obtained value was comparable to the normal control (73.1±10.6 Umol/min/mg protein). Anti-inflammatory properties at doses of 100, 300 and 500mg extract/kg body weight exhibited inhibitory effect on carrageenan-induced rat paw oedema in a dose-dependent manner. Respectively, Morinda lucida leaf extracts showed percentage (%) inflammatory inhibition of 83.53±10.50, 91.67±8.33, and 100.00±0.00. Stem bark extract showed 58.33±15.37, 91.67±8.33 and
91.67±8.33. Fruit extract showed 58.33±15.37, 75.00±17.08 and 100.00±0.00; and root extract showed 100.00±0.00 at all the doses. In the serobiochemical assays, liver function tests showed lowest AST activity in the root extract among the extract post-treatment group
while the fruit extract showed the lowest among the pre-treatment group (p<0.05). The ALT activity of all the different extracts demonstrated significant reductions (p<0.05) in the posttreatment
(hepatocurative) group as compared to the positive control. A similar pattern of
lowered ALT activity was also observed in the pre-treatment group, with the bark extract showing the lowest value. Total bilirubin concentration was significantly lower (p<0.05) in all the extracts post-treatment group, with values obtained for leaf and fruit being comparable
to the normal control group. In the extract pre-treatment group, all the extracts showed
significantly lower total bilirubin concentration than the ‘CCl4 only’ group (p<0.05) and comparable to the values obtained for the vitamin groups. Lipid profile studies showed that
cholesterol-lowering effect of the extracts was most effective in the post-treatment group administered with bark extract even though all the different extracts exhibited similar effects.
But in the pre-treatment group, the leaf extract was most active. HDL concentration was significantly higher (p<0.05) among the extracts pre-treated groups except in the leaf extracts
where there was no significant difference, compared with the ‘CCl4 only’ group. Also, in the extract post-treatment group, all the groups showed significantly higher (p<0.05) HDL concentration than the ‘CCl4 only’ group. The LDL concentration was only significantly
lower among the bark extract post-treatment group, while in the extract pre-treatment group,
the leaf and bark presented significantly lower (p<0.05) LDL concentrations, concentrations were lowest in the root extract pre-treated group. All the pre-treatment groups
were however lower in total urea than the ‘CCl4 only’ group. In the post-treatment groups all
the extracts demonstrated lowered total urea concentration than the ‘CCl4 only’ group. Total
protein concentration was higher in all the post-treatment groups than ‘CCl4 only’ group. In
the extract pre-treatment group, only the leaf and root extracts group showed higher total
protein concentration than the ‘CCl4 only’ group. Cytotoxic properties using the brine shrimp
assay which included the hatchability assay and lethality assay revealed that while that of
root, leaf, and stem bark showed half-inhibitory concentration (IC50) of 190mg/L, 210mg/L
and 407mg/L respectively, the fruit extract showed IC50 of 170mg/L and exerted total
hatchability inhibition on the artemia cysts at 600mg/L concentration. The lethality assay
revealed that the leaves possessed the highest cytotoxicity properties among all the plant
parts, at 316.2mg/L followed by the root extract at 398.1mg/L while the least was the fruit
extract at 631mg/L. Plasmid nicking assay showed the genotoxic properties of the extracts at
lower concentration of 100μg/10μL. Only the bark extracts demonstrated genoprotective
effect. The genotoxic properties of the extracts increased with increased concentration.
Histological slides of liver and kidney tissues showed that all the fruit, leaf and root extracts
possessed only slight to non-hepatoprotective or hepatocurative effects except the bark
extract, and whose effects on hepatoprotection was most pronounced. These results suggest
that different parts of Morinda lucida possess significant anti-oxidant, anti-inflammatory,
hepatoprotective/ hepatocurative, cytotoxic and genotoxic properties (at lower concentrations
however), to justify their various uses in folklore medicine.
comparable to
the normal group. Triglyceride concentrations were significantly lower in all the extract posttreatment
groups when compared to ‘CCl4 only’ group (p<0.05). A similar trend was also
observed in the extracts pre-treatment groups, presenting significantly lower (p>0.05)
triglyceride concentrations than the ‘CCl4 only’ group. Kidney function assays viz: total
creatinine and total urea concentration were also carried out. Although, all the parts showed a
reduction in creatinine concentration (p<0.05) in both the extract pre-treated and post-treated
groups, creatinine levels showed that the most significant nephroprotective effects (p<0.05)
was exhibited by the leaf extract while the extracts of the other plant parts did not. Total urea
Description
IN PARTIAL FULFILMENT OF THE REQUIRMENT FOR THE
AWARD OF DOCTORATE DEGREE IN BIOCHEMISTRY
DEPARTMENT OF BIOCHEMISTRY, AHMADU BELLO
UNIVERSITY ZARIA
Keywords
EVALUATION, ANTIOXIDANT, ANTI-INFLAMMATORY, HEPATOPROTECTIVE, CYTOTOXIC, PROPERTIES, MORINDA, LUCIDA, Benth