Abstract:
Background: Both young and old leaves of Vernonia amygdalina (VA) are traditionally used to treat inflammation,
pain and fever. However, the efficacy of young and old leaves for treating these ailments have not been com-
pared till date.
Aim: To ascertain the effect of young and old leaves of VA in managing inflammation, pain and fever.
Methods: Both quantitative and qualitative phytochemical screening of ethanol extracts of young (EthYL) and
old (EthOL) leaves of VA were performed. The anti-inflammatory activity of orally administered EthYL and
EthOL (50–200 mg/kg) and Diclofenac (10 mg/kg) were evaluated in carrageenan-induced inflammation model
in rats. Antipyretic activity of EthYL, EthOL and Aspirin (25 mg/kg) were assessed in the Baker’s yeast-induced
pyrexia model. Anti-allodynic effect of both extracts were evaluated by inserting inflamed paws of rats in cold
water. Antinociceptive property of the extracts were assessed using tail withdrawal and formalin-induced no-
ciception test. Histopathological examination of the paws was performed, in addition to formalin test to un-
derstand the possible mechanism of action of the extracts. Negative control rats received 2 ml/kg normal saline
in all tests.
Results: The amount of flavonoids, alkaloids, tannins, and phenolics were significantly (p < 0.05) higher in
EthOL than EthYL, while saponins were significantly higher (p < 0.05) in EthYL than EthOL. The antioxidant
ability and total antioxidant capacity were significantly (p < 0.05) higher in EthYL than EthOL. However, this
was significantly (p < 0.05) lower than the anti-oxidant activity of Ascorbic acid. A dose-dependent increase in
anti-inflammatory, antipyretic and antinociceptive properties were observed in both EthYL and EthOL, similar to
the standard drugs. Mast cell degranulation accompanied by vasodilatation and high leukocytosis were observed
in the negative control, but were markedly low in extract treated groups. Both extracts mediated their analgesic
effect through opioidergic and nitric oxide pathways with EthYL additionally implicating the muscarinic cho-
linergic system.
Conclusion: Although both EthYL and EthOL alleviate inflammation, pyrexia and nociception, EthYL of VA was
found to be more potent than EthOL.
