Date Published: April 11, 2013
Publisher: Hindawi Publishing Corporation
Author(s): Christian Agyare, Anita Serwaa Dwobeng, Nicholas Agyepong, Yaw Duah Boakye, Kwesi Boadu Mensah, Patrick George Ayande, Martin Adarkwa-Yiadom.
Microbial infections of various types of wounds are a challenge to the treatment of wounds and wound healing. The study was to investigate antimicrobial and antioxidant properties of methanol leaf and stem bark extracts of Kigelia africana and methanol leaf and root extracts of Strophanthus hispidus and also to determine wound healing properties of the extracts. The antimicrobial activities of the methanol extracts were determined against two Gram-positive and two Gram-negative bacteria and a fungus using agar diffusion and micro-dilution methods. The antioxidant activity was determined using 1,1-diphenyl-2-picryl–hydrazyl (DPPH) method. The influence of the extracts on rate of wound closure was investigated using the excision wound model and histopathological investigation of treated and untreated wound tissues performed. The MICs of leaf extract of K. africana against test organisms were 2.5–7.5 mg/mL and stem bark extract were 2.25–7.5 mg/mL. The leaf extract of S. hispidus had MIC range of 2.5–7.5 mg/mL and 2.5–10 mg/mL for root extract. The IC50 of leaf and stem bark extracts of K. africana were 56.9 and 13.7 μg/mL, respectively and leaf and root of S. hispidus were 49.8 and 45.1 μg/mL, respectively. K. africana extracts (7.5% w/w) showed significant (P < 0.05) wound contraction at day 7 with 72% of wound closure whiles significant (P < 0.05) wound contractions were observed on day 11 for stem bark of K. africana, leaf and root extracts of S. hispidus. Wound tissues treated with the extracts showed improved collagenation, re-epitheliazition and rapid granulation formation compared with untreated wound tissues. The extracts were found to contain alkaloids, saponins, tannins, flavonoids, carbohydrates, and sapogenetic glycosides. The HPLC finger-printing of the extracts were developed. The leaf, stem bark and root extracts of K. africana and S. hispidus exhibited antimicrobial, antioxidant, and enhanced wound healing properties and these may justify the medicinal uses of the plants for treatment of microbial infections and wounds.
Wound is most commonly used when referring to injury to the skin or underlying tissues or organs by a blow, cut, missile, or stab. Wound also includes injury to the skin caused by chemicals, cold, friction, heat, pressure and rays, and manifestation in the skin of internal conditions, for example, pressure sores and ulcers . Wounds have a tremendous impact on the healing healthcare economy. Chronic wounds represent a major health burden and drain on the healthcare resources in the world including Ghana .
The present investigation describes some of the biological activities including antimicrobial and wound healing properties of the leaves, stem bark, and roots extracts from the tropical plants K. africana and S. hispidus. Plant products are potential wound healing agents, and largely preferred because of their widespread availability, less or no side effects, and effectiveness as crude preparations . The phytochemical screening of the dried leaves and root of S. hispidus revealed the presence of tannins, alkaloids, saponins, steroids, carbohydrates and sapogenetic glycosides, and flavonoids in the leaves. Alkaloids were absent in the dried leaves and stem bark of K. africana and saponins, steroids, carbohydrates, and sapogenetic glycosides were present in both plant materials. Flavonoids were also found in the leaves of K. africana (Table 1). The HPLC finger-printing of the extracts (KAL, KASB, SHL, and SHR) was also developed for identification and quality control purposes (Figures 1, 2, 3, and 4).
The methanol leaf and stem bark of K. africana and methanol leaf and root extracts of S. hispidus exhibited antioxidant, antimicrobial activities with MIC ranges of 2.25 to 7.5 mg/mL and 2.5 to 10 mg/mL, respectively, against the test organisms, enhanced wound healing properties and these pharmacological properties may justify the medicinal uses of these plants for treatment of microbial infections and wounds. Bioactivity guided fractionation and isolation of the bioactive compounds responsible for the biological activities would be carried out.