Extraction was by cold maceration using methanol. The extract was concentrated in vacuo to yield a brown solid of 120.191 g. The crude methanol extract was partitioned into n-hexane 0.1 g, dichloromethane 2.5 g, ethylacetate 4.6 g, and methanol 10.0 g fractions via coarse chromatography. Secondary metabolites identified; 21.73±0.36% alkaloids, 40.78±0.27% flavonoids, 15.99±0.044% saponins, 6.088±0.06% tannins, 3.086±0.03% terpenoids and 12.13±0.01% Cardiac Glycosides. Acute toxicity test showed no death in the rats administered with low dose (1000 mg/kg) and high dose (6000 mg/kg). Analgesic activities of crude methanol extract and fractions showed that at a low dose of 4000 mg/kg of the extract and the fractions have percentage inhibition of pains as methanol crude (63.48±4.62), methanol fraction (79.14±7.39), dichloromethane fraction (60.79±6.69), ethylacetate fraction (23.26±9.75) and n-hexane fraction (64.82±9.75). At a high dose of 8000 mg/kg, the percentage inhibition of pain was 5200±2.00, 71.87±7.04, 80.31±6.20, 45.61±12.60 and 43.87±8.13. Statistical analysis; P>0.05 confidence level, methanol fraction recorded highest analgesic activities while ethylacetate fraction had least.

Pulverized leaves samples of Newbouldia laevis were extracted by cold maceration using methanol. The extract was concentrated in vacuo to yield a reddish brown solid of 120.191 g. The crude methanol extract was partitioned into n-hexane 0.1 g, dichloromethane 2.5 g, ethyl acetate 4.6 g, and methanol 10.0 g, fractions via coarse chromatography. Methanol fraction gave the highest yield and was subjected to further purification using repeated column chromatography to yield pure components, namely NLM24 (R f 0.48), EAc:n-hex:MeOH (4:5:1) and NLM19 (R f 0.47), EAc:n-hex:MeOH, respectively. These pure fractions were subjected to 1 H NMR, 13 C, COSY, HSQC and HMBC spectroscopy. Pheophytin A and β-amyrin were proposed as the structures of the isolated compounds. Even though the pure fractions were not used for the analgesic activity, the literature reveals that pheophytin A & β-amyrin are potent analgesics.