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A methanolic extract of Russelia equisetiformis whole plant was studied for anti-inflammatory and analgesic activities in rats and mice using carrageenan-induced rat paw oedema, acetic-acid-induced writhing and tail-flick test. The extract, at 10, 20 and 40 mg/kg, significantly (P <0.05) inhibited carrageenan-induced oedema in rats. Abdominal constriction induced by acetic acid was also inhibited by the extract, within the same dose range. The extract at the same dose also prolonged the latency period in the tail-flick response test, which was reverted by naloxone. The results suggested that the extract possesses potential anti-inflammatory and analgesic properties.

Aims: This study was designed to investigate the effects of crude ethanol and partition extracts of Newbouldia laevis leaves on excitotoxin-induced stereotypy in mice. Place and Duration of Study: The study was carried out in the Laboratory of the Department of Pharmacology and Therapeutics, College of Health Sciences, Ladoke Akintola University of Technology, Ogbomoso, Nigeria, between July and October, 2020. Methodology: Following pretreatment of mice with graded doses (150 - 600 mg/kg b.w) of crude extract (NLE) and partition fractions [n-butanol partition fraction (BPE), n-hexane partition fraction (HPE) and ethylacetate partition fraction (EAPE)] of Newbouldia laevis leaves, stereotypy was induced by the administration of methamphetamine (35 mg/kg b.w) and apomorphine (5mg/kg b.w.), and stereotypy scores were recorded thereafter. The effects of BPE and NLE on catalepsy were also determined. Statistical significance was taken at P<0.05 Results: In both apomorphine and methamphetamine models, stereotyped behavior was significantly decreased (P<0.05) in the treated mice compared to the control. The degree of protection offered by Newbouldia laevis extracts against excitotoxin-induced stereotypy was in the order: BPE>NLE>EAPE>HPE. In the catalepsy test, BPE (600 mg/kg b.w) significantly potentiated haloperidol-induced catalepsy compared to control (P<0.05). Likewise, NLE significantly increased catalepsy compared to control (P<0.05). Conclusion: Findings from this study indicate that crude and partition extracts of Newbouldia laevis leaves attenuated stereotypy in methamphetamine and apomorphine models, and thus could be effective remedy for schizophrenia-like psychosis.

Objective: The study was designed to investigate the anti-nociceptive activity of Euphorbia hirta leaf and its possible mechanism of action. Methods: The extract of Euphorbia hirta obtained from the leaf was prepared as per standard procedures and evaluated at the three doses (300, 600, and 1200 mg/kg, i.p). The extract was screened for anti-nociceptive activity using heat-induced (tail-flick) and chemical-induced (acetic acid-induced writhing and formalin-induced paw lick) nociception models in mice. The possible mechanism of action of the extract was evaluated using antagonists of notable nociceptive pathways. Results: Intraperitoneal administration of Euphorbia hirta extract at the doses of 600 and 1200 mg/kg significantly (p<0.05) reduced the formalin-induced paw licking in both neurogenic and inflammatory phases of the test. While administration of the extract at the dose of 300 mg/kg significantly inhibited the pain due to formalin in the inflammatory phase but not in the neurogenic phase. The anti-nociceptive effect of Euphorbia hirta extract increased the reaction time to thermal stimulus, also inhibited the acetic acid-induced writhing dose-dependently. The anti-nociceptive effect exhibited by Euphorbia hirta extract in the formalin test was reversed by the administration of naloxone, theophylline, and atropine. Glibenclamide, nifedipine, and yohimbine, however, did not significantly block the anti-nociceptive effect of the extract. Meanwhile, methylene blue administration enhanced the anti-nociceptive effect of the extract. Conclusion: The results indicated that Euphorbia hirta extract produces a dose-related anti-nociceptive effect in several models of chemical and thermal pain, through mechanisms that might involve interaction with adenosine, cholinergic, and opioid receptors.

Objective: This study investigated the anti-nociceptive and anti-inflammatory activities of the aqueous extract of Ficus capensis (AEFC) by bio-guided fractionation. Methods: The anti-nociceptive and anti-inflammatory effects of AEFC (250, 500, 1000 mg/kg, i.p) were assessed using acetic acid-induced writhing, hot plate, tail-flick, formalin tests, and carrageenan-induced paw oedema respectively. The AEFC was fractionated base on polarity different into butanol, ethyl acetate, and n-hexane fractions. The fractions (500 mg/kg) obtained were subjected to the same experimental procedures mentioned above. The EAF, which exerted the most productive activities, was further subjected to fractionation procedures that yielded six fractions (labeled CF1-CF6). These fractions (200 mg/kg) were tested for potential anti-nociceptive and anti-inflammatory activities. Notable antagonists (Naloxone and atropine) of nociceptive pathway were used to evaluate the mechanism of the anti-nociceptive action of F. capensis. Results and Discussion: The AEFC, BF, EAF, and CF4 caused a significant (p<0.05) reduction in the number of abdominal writhes, an increase in reaction time against the hot plate, tail-flick tests, and a significant (p<0.05) inhibition in both phases of formalin test. The AEFC, BF, EAF, CF4, and CF6 caused a significant (p<0.05) inhibition of paw oedema development due to carrageenan. Atropine significantly reversed the anti-nociceptive effect of CF4 in both phases of the formalin test. The result obtained revealed that CF4 produced central and peripheral anti-nociceptive effects, while CF6 is peripherally mediated. Conclusion: The results support the traditional uses of F. capensis in the treatment of various diseases associated with pain and inflammation. The column fraction CF4 exhibited muscarinic receptor-mediated anti-nociceptive activity.