In-vivo analgesic activity of ethanol leaf extract of Sphenocentrum Jollyanum in albino mice

Abstract

This study assessed the in-vivo analgesic activity of ethanol leaf extract of Sphenocentrum jollyanum in albino mice using analgesic models such as acetic acid-induced abdominal writhing, formalin-induced paw licking and thermally-induced pain in mice. Acetylsalicylic acid (ASA) was used as the reference drugs for the acid-induced abdominal writhing and formalin-induced paw licking while Dexamethasone was used as standard drug for thermally-induced pain. A total of seventy-five matured Swiss Albino mice of both sexes weighing between 15 – 25 g (divided into three groups of 25 mice each for the 3 different studies) were used for this study. They were randomly divided into 5 groups of five mice each. Group I served as the normal control and received 10 mL/kg body weight (bw) distilled water. Group II (Standard control), received standard drugs- Acetylsalicylic acid (ASA) or Dexamethasone. Groups III, IV and V received 474.34, 948.68 and 1423.03 mg/kg bw ethanol leaf extract of S. jollyanum respectively. All administration was done intraperitoneally. The animals were fed normal rat pellet and had water ad libitum. The results showed a significant (p< 0.05) dose dependent reduction in the acetic acid-induced abdominal writhing and formalin-induced paw licking at all doses (Groups III-V) compared with acetylsalicylic acid standard drug Group II. In the acetic acid-induced writhing and formalin paw licking models, the extract had the highest writhing and paw licking effects of 37.40± 0.68 and 28.60 ± 0.60 at the highest dose of 1423.03 mg/kg respectively. Similarly, the extract caused a dose-dependent increase in percentage inhibition of abdominal writhing and paw licking effects at total timing of 105 mins with the highest dose of 1423.03 mg/kg respectively. Additionally, the extract (groups III-V) and standard drug (II) demonstrated a dose-dependent (p < 0.05) increase in PRT compared with control group I, with the standard drug dexamethasone (group II) having the highest effect. Sphenocentrum Jollyanum leaves extract also showed significant increase in PRT from 135 to 190% compared to control group I. The result obtained from this study suggests that the extract of Sphenocentrum Jollyanum leaf may be an effective analgesic agent that may act by the inhibition of prostaglandin synthesis or via peripheral mechanism of pain inhibition.