Antinociceptive activities of extracts of croton megalocarpus hutch (eurphobiaceae) using animal models
Abstract
The use of plant parts for therapeutic purposes has been widely practiced in Africa. One of the
trees used for fever and analgesia is Croton megalocarpus. However, animal studies have not
been done to evaluate this claimed antinociceptive activity. The objective of the study was to
investigate the antinociceptive activity of Croton megalocarpus using animal models of pain.
The nociceptive tests used in this experiment were the Writhing, Tail Flick and the Formalin
tests. Swiss albino mice of both sexes were used in a randomized design. In the writhing test,
the mice were injected intraperitoneally with doses of the Extract, Aspirin and the Vehicle. Sixty
minutes later, they were injected with 0.1 ml of 0.6% acetic acid and the number of writhes
observed. In the tail flick test, the mice were injected intraperitoneally with doses of the
Extract, Morphine and the Vehicle. An hour later, a light beam was focused on the animal's tail
and a timer started. When the animal flicked its tail, the timer was stopped and the time
recorded. The same was repeated after thirty, sixty and ninety minutes. In the formalin test,
the mice were injected with doses of the Extract, Morphine, Aspirin and the Vehicle. An hour
later, they were injected with 0.1 ml of 5% formalin in the sub plantar region of the hind paw.
The time spent in pain behavior was then recorded. In the writhing test, all the doses of the
extract exhibited significant (p < 0.05) antinociceptive effects compared to the vehicle. In the
tail flick test the 50, 100 and 200 mg / kg doses of the extract exhibited significant (p < 0.05)
antinociceptive effects compared to the vehicle. In the formalin test, the 50 mg / Kg dose of the
extract did not exhibit significant antinociceptive effect whereas the 100 and 200 mg / Kg doses
exhibited significant effects (p < 0.05) in the early phase compared to the vehicle. In the late
phase, all the doses of the extract exhibited significant (p < 0.05) antinociceptive effects
compared to the vehicle. These results showed that the extracts of C. megalocarpus exhibited
peripheral, chronic and central antinociceptive activity hence it probably contains
phytochemicals that may be of value in development of a novel drug for analgesia. However,
further studies need to be done to elucidate nature and mechanism(s) of action of these
metabolites
Publisher
University of Nairobi
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Attribution-NonCommercial-NoDerivs 3.0 United StatesUsage Rights
http://creativecommons.org/licenses/by-nc-nd/3.0/us/Collections
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