2021, Vol. 9, Issue 2, Part A

author(s)
Florence Chimezie Nwinyi, Paul Abdu, Shehu Naallah Alhaji Saidu, Joseph Omamegbe and Adamu Mohammed

abstract
Stereospermum kunthianum Cham (Family; Bignoniaceae) is a plant that has its different parts used in traditional medicine for the treatment of different ailments. Its stem bark extract is used for treatment of wounds, ulcers, gastritis, bronchitis and other pain and inflammatory related health conditions. This study was prompted by the need to authenticate some of these ethnomedicinal claims. The stem bark of S. kunthianum was successively macerated in 80 % v/v methanol and the extract was used to evaluate its usefulness in pain and inflammatory conditions. The aqueous-methanol extract of S. kunthianum was analysed for phytochemical constituents. Its acute toxicity profile was determined in rats and mice. Anti-inflammatory activity of the extract was evaluated using fresh egg albumin-induced paw oedema model and formalin-induced paw oedema model in rats. The extract was also tested for anti-nociceptive effect using acetic acid-induced writhing test in mice and formalin-induced pain test in rats. The results revealed that saponins, terpenes, tannins and steroids were present in the extract. The estimated oral and intraperitoneal median lethal dose (LD₅₀) of the extract in rats was ≥ 5,000 mg/kg. The intraperitoneal LD₅₀ of the extract in mice was also ≥ 5,000 mg/kg. The extract (100, 200 and 400 mg/kg i.p) reduced egg albumin-induced paw oedema in rat over a period of 120 min (2 h). The reduction was significant (p < 0.05) up to 60 min. and the percent inflammatory inhibition for the extract was comparable to that of acetyl salicylic acid (ASA, 100 mg/kg i.p). Formalin-induced oedema test also revealed that S. kunthianum reduced paw oedema in rats up to Day 6 and the reduction effect was higher than that of ASA (100 mg/kg p.o). Acetic acid-induced writhing test for anti-nociception showed that S. kunthianum (100 – 400 mg/kg i.p) significantly (p < 0.05) reduced the number of acetic acid-induced writhes in mice over 120 min and the reduction was dose-dependent. The extract doses of 200 and 400 mg/kg had higher percent inhibition of nociception than the tested dose of acetyl salicylic acid (100 mg/kg p.o). Anti-nociceptive study also revealed that S. Kunthianum (100, 200 and 400 mg/kg i.p) caused a significant (p < 0.05) reduction of formalin-induced pain at the late phase (15 – 60 min). The reduction was not dose-dependent and was comparable to that of ASA (100 mg/kg i.p). The extract (100, 200 and 400 mg/kg i.p) produced non-significant pain inhibition in the early phase (0 – 10 min). In conclusion, the study showed the justification for the ethno-medicinal use of S. kunthianum stem bark extract for the treatment of inflammatory and pain-related health conditions. The findings are also suggestive of peripheral mechanism of action. S. kunthianum stem bark extract therefore has the potential to be developed as anti-inflammatory and analgesic agent.