Phytochemical screening of aqueous leaf extract of Blighia sapida K.D. Koenig (Sapindaceae) and its analgesic property in mice

Ethnopharmacological relevance: Blighia sapida is traditionally used in treating intercostal pain, psychosis, stomach ache, back pain, and skin diseases. However, there is limited information on the scientific basis for its use traditionally in the treatment of pain.

Aim of study: To identify the major constituents in the aqueous leaf extract of Blighia sapida (AEBS) and to assess its analgesic properties in mice.

Materials and methods: Bioactive compounds were identified and quantified in AEBS by High Performance Liquid Chromatography/Photodiode Array Detector (HPLC/DAD). Analgesic activity of AEBS was assessed at doses of 125, 250, and 500 mg/kg p.o., using animal models.

Results: Chlorogenic acid, saponins, tannins, caffeic acid, quercetin, gallic acid, pyrogallol, quinine, caffeine, and nicotine were identified. At doses 250 mg/kg (p < 0.05) and 500 mg/kg (p < 0.01), AEBS significantly inhibited acetic acid induced writhing in comparison with the control. It also significantly inhibited pain in the inflammatory phase of the formalin induced paw licking test at 250 mg/kg (p < 0.01) and 500 mg/kg (p < 0.05) doses, in comparison with the control. It did not inhibit pain in the neurogenic phase of the formalin paw licking and in the hot plate tests.

Conclusion: Blighia sapida leaf extract possesses analgesic activity that is mediated by peripheral mechanisms but not through central mechanisms.