Abstract

â�?��?Evaluation of Aqueous Methanol Stem Bark Extract of Stereospermum kunthianum for Wound Healing Effects in Alloxan-induced Diabetic Ratsâ�?�

Author(s): Ifeadi Chekwube Nkemjika

Background and Purpose: The stem bark extract of Stereospermum kunthianum (Family: Bignoniaceae) is used in traditional medicine to treat wounds, bronchitis, pneumonia, coughs, gastritis, rheumatic arthritis, ulcers, dysentery, leprosy, venereal diseases, and other inflammatory and pain-related health conditions in humans. The aim of this study was to evaluate the wound healing, analgesic and anti-inflammatory properties of the stem bark extract of S. kunthianum in alloxan-induced diabetic rats for development into a drug development. Experimental Approach: The aqueous-methanol extract of S. kunthianum was analyzed for phytochemical constituents. The aqueous-methanol stem bark extract of the plant was evaluated for 72 h for its acute toxicity in the adult Wistar rats. Similarly, the extract of Stereospermum kunthianum was evaluated for wound healing using excision and incision wound healing models in diabetic-induced rats. Results: The results revealed that saponins, terpenes, tannins and steroids were present in the extract. Its acute toxicity profile was determined in the diabetic rats. In the acute toxicity studies, there was no observed toxicity sign up to the dose up to 5000 mg/kg p.o. and i.p. The estimated oral and intraperitoneal median lethal dose (LD50) of the extract was ≥ 5,000 mg/kg. The S. kunthianum stem bark extract (100 mg/kg p.o, 200 mg/kg p.o, 400 mg/kg p.o) caused significant reduction of wound area. The excision wound contraction (%) in rats treated with S. kunthianum stem bark extract (100 mg/kg p.o, 200 mg/kg p.o, 400 mg/kg p.o.) was most effective and had 100% wound contraction as when compared to the controls groups (distilled water; 10 ml/kg and Vitamin C; 100 mg/kg, p.o.) which had 92.3% and 88.0% respectively. S. kunthianum stem bark extract (100, 200, 400 mg/kg, p.o.) caused a complete (100%) epithelialization after 25 days of treatment, while Vitamin C (100 mg/kg p.o.) and the negative control (distilled water; 10 ml/kg) had epithelialization of 85% and 86% within the said period. The extract (400 mg/kg, p.o.) produced the shortest mean wound closure time (WC50) of 5 days, the extract (100, 200 mg/kg, p.o.) had WC50 of 6 days and 7 days, respectively, while Vitamin C (100 mg/kg, p.o) and distilled water (10 ml/kg, p.o.) had the mean wound closure time (WC50) of 8 days each. In the Incision wound studies, the S. kunthianum stem bark extract (100, 200,400 mg/kg, p.o) showed a progressive rate of wound repair with increasing doses of the extract. However, there was a dose-dependent increase in the tensile strength with values of 983.5 g, 984.4 g and 1066.0 g when the extract was tested at 100, 200 and 400 mg/kg, respectively. Conclusion: The results obtained from the research corroborated the ethno-medicinal claims and have given the scientific justification for the use of S. kunthianum stem bark extract for wound healing. Implication: The S. kunthianum stem bark extract therefore has the potential to be developed as a wound healing agent. Key Words: Wound healing, Diabetes mellitus, Stereospermum kunthianum stem bark extract, surgical wounds (excision and incision), tensile strength, phytoconstituents, wound contraction, mean wound closure time, wound epithelialization.