ANTINOCICEPTIVE AND ANTIOXIDANT EFFECTS OF ETHANOL EXTRACT AND RESIDUAL FRACTION OF Rothmannia longiflora SALISB (RUBIACEAE) IN NEUROPATHIC PAIN INDUCED BY CHRONIC CONSTRICTION INJURY OF THE SCIATIC NERVE

Rothmannia longiflora is a plant found in Nigeria and most African countries, which is used in the management of pain and inflammation. The anti-nociceptive properties of the ethanol leaf extract and residual aqueous fraction of Rothmannia longiflora (EERL and RAQF) in rats was studied after the qualitative screening and acute toxicity studies. The antinociceptive properties of EERL and RAQF (500 and 1000 mg/kg p.o) were evaluated using a neuropathic pain model in rats. The result of qualitative evaluation of EERL and RAQF revealed the presence of flavonoids, tannins, saponins, steroids, glycosides, anthraquinones and phenols. The acute oral toxicity (LD50) of the EERL and RAQF in rats was found to be greater than 5,000 mg/kg body weight. The result of this work demonstrated the ability of EERL and RAQF to significantly increase the pain latency time, p<0.01(9.40) on D7, p<0.01(10.72) on D14, p<0.05(11.72) and p<0.05(8.73) on D7, p<0.01(10.30) on D14, respectively, compared to the control. Similarly, the concentrations of SOD increased significantly p<0.05(1.58), p<0.01(1.60); CAT p<0.01(1.80), p<0.01(1.62); GSH p<0.01(1.50), p<0.01(1.36) compared to the control while the concentrations of MDA significantly decreased p<0.001(111.88), p<0.05(132.46) compared to control at 1000 mg/kg, thus validating the herbal medicinal activity of the plant for the management of neuropathic pain.