Evaluation of the Anti-nociceptive Effect of the Ethanol Leaf Extract and Ethyl Acetate Fraction of Eleusine indica Linn, Baertn.
Ezeugo, Ogonna1, *Ofokansi Martha, Nneoma2, Akah Peter, Achunike1,2
- Department of Pharmacology and Toxicology, Nnamdi Azikiwe University, Awka, Anambra State, Nigeria
- Department of Pharmacology and Toxicology, University of Nigeria, Nsukka, Nigeria, Enugu State, Nigeria.
|Key words: Eleusine indica, Anti-nociceptive, Ethyl Acetate, Phytoconstituents.
*Corresponding author: firstname.lastname@example.org;
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Efforts made over the decades to develop effective therapies for pain have been hampered by the cost and adverse effects of conventional anti-nociceptive. There is still need for effective, potent and safe drugs for pain. This study investigated the anti-nociceptive activity of the ethyl acetate fraction of the ethanol leaf extract of E. indica in rodents. The leaves were extracted with ethanol by cold maceration and the extract was subjected to bioassay-guided liquid-liquid chromatographic separation to obtain n-hexane, ethyl acetate, butanol and aqueous fractions. Only the ethylacetate fraction (ETF) exhibited significant anti-nociceptive activity. The oral acute toxicity (LD50) of the extract and the phytochemical constituents of the extract and the ethyl acetate fraction were determined. Pain was induced in mice experimentally using hot plate and acetic acid. The experimental mice were given 200, 400 and 600 mg/g of the extract or fraction. Tween 80 (3 % w/v), morphine or piroxican served as control treatments. The oral LD50 of the extract was above 5000 mg/kg. Saponins, tannins, flavonoids, alkaloids and steroids were the most abundant phytocompounds in the EE while ETF contained mainly tannins and flavonoids. Against thermal induced nociception the extract and fraction evoked significant (p < 0.05) prolongation of the reaction time which peaked 90 minutes post administration. At dose of 600 mg/kg of both the extract and fraction, and 50 mg/kg of diclofenac sodium, the post treatment reaction time at 90 min was 8.8±0.3, 10.5±0.5 and 15.8±0.6 seconds, respectively. Both the EE and ETF displayed dose-dependent and significant (p < 0.05) inhibition of acetic acid-induced writhing. At 600 mg/kg, the ethyl acetate fraction produced 67.71 % inhibition of writhing reflex that was similar to 65.92 % produced by piroxicam (100 mg/kg). The findings of this study indicate that the leaves of Eleusine indica have potential in the treatment of pain and that the anti-nociceptive activity may be attributed to phytoconstituents present mainly in the ethyl acetate fraction.