Antinociceptive Activity of Methanol Leaf Extract of Newbouldia laevis in Wistar Rats.
Gideon Kelechi Madubuike¹*, Omeh Ndukaku Yusuf ², Kelsi Chinemerem Ndukwe², Aruh Ottah Anaga³.
- Department of Veterinary Physiology and Pharmacology, Michael Okpara University of Agriculture, Umudike.
- Department of Biochemistry, Michael Okpara University of Agriculture, Umudike.
- Department of Veterinary Physiology and Pharmacology, University of Nigeria, Nsukka
| Key words:
Antinociception, Newbouldia laevis, acetic acid, formalin, peripheral. .
*Corresponding author: madubuike.kelechi@mouau.edu.ng Page No.: 23-29 Volume: 2, Issue 1 2021 Trends in Natural Products Research Copy Right: NAPREG |
Abstract Side effects attributable to currently available pain killers necessitated the search for novel analgesics with higher safety index. In Nigerian traditional medicine, Newbouldia laevis is reputed for alleviating pain. The present study investigated the methanol extract of N. laevis for antinociceptive potential in Wistar rats. Dried and pulverized leaves (550 g) of N. laevis were extracted with 80 % methanol (1.65 L) by cold maceration. Acute toxicity and preliminary phytochemical analysis of the extract were done following standard methods. Analgesic models adopted for the study included: acetic acid-induced writhing reflex, hot plate test, tail immersion and formalin tests. In each of the models thirty adult Wistar rats were assigned to five groups (n = 6). Group 1 (control) received distilled water (5 ml/kg) while group 2 rats were dosed with 20 mg/kg tramadol (reference drug). Groups 3-5 received 200, 300 and 400 mg/kg of the extract, respectively. All treatments were administered orally. The acute toxicity test produced no death even at highest dose of 5000 mg/kg. The preliminary phytochemical analysis revealed the presence of alkaloids, flavonoids, glycosides, polyuronoids and tannins. The extract significantly reduced abdominal constrictions in the treated rats, with 800 mg/kg evoking 44 % antinociceptive activity against 89 % anticociception achieved by tramadol. In the hot plate and tail immersion tests, the extract caused no significant difference in the rats’ response to noxious stimuli. However, during the second phase of the formalin test, the extract significantly reduced the number of flinches in the treated rats when compared with the control. The results of this study showed that N. laevis methanol leaf extract possesses significant peripheral antinociceptive property. This validates its use in ethno medicine to minimize or abolish pain. |