Antinociceptive Effect of Ethanolic Extract of Hybanthus enneaspermus Leaf in Rats

Pharmacological mechanisms involved in the analgesia induced by ethanol extract of <em>Hybanthus enneaspermus</em> leaves

“… 30 We have suggested that the anti-nociceptive action of EEHE is both centrally- and peripherally-mediated. 11 The present study validates our previously reported anti-nociceptive effect of EEHE and provides additional information that opioidergic pathway greatly contributes to EEHE-induced analgesia during both TFL and formalin tests, while histaminergic and adrenergic pathways also partly contribute to it during the tail-flick test only but not during the formalin test.…”

“…Forty-two male rats were randomized into seven treatment groups (n=6 rats in each group). Group I (control) received distilled water (10 mL/kg) while groups II and III received acetaminophen (the reference drug, 100 mg/kg ip) and EEHE (1000 mg/kg po), 11 respectively. Groups IV–VII were pretreated with cimetidine (50 mg/kg ip), 22 naloxone (5 mg/kg ip), 23 propranolol (0.15 mg/kg ip), 24 and prazosin (0.15 mg/kg ip), 25 respectively, 20 minutes before EEHE (1000 mg/kg po) treatment.…”

“…For instance, Hybanthus enneaspermus leaves are known as “ēwé ābíwéré” in Yoruba language (meaning a leaf that induces painless or fast delivery or both during labor) because of their widespread ethnopharmacological use as a traditional analgesic herb, especially to reduce labor pain in pregnant women. 11 While Awobajo et al 12 demonstrated the uterotonic effect of their aqueous extract in isolated uterine muscles of pregnant rats, Afolabi et al 11 demonstrated the dose-dependent anti-nociceptive effect of their ethanol extract in male Wistar rats. Phytochemical screening of H. enneaspermus leaves extract 13 has shown that the leaves contain saponins, tannins, and flavonoids, which are known to have analgesic effect in animals.…”

“…Phytochemical screening of H. enneaspermus leaves extract 13 has shown that the leaves contain saponins, tannins, and flavonoids, which are known to have analgesic effect in animals. 14 , 15 Afolabi et al 11 speculated that the anti-nociceptive effect exhibited by the ethanol extract of H. enneaspermus leaves (EEHE) might be due to the synergistic action of its phytochemical components. However, the pharmacological mechanisms involved in the analgesic action of the leaves have not been determined.…”