Kwesi Boadu Mensah

Antimicrobial, Antioxidant, and Wound Healing Properties of Kigelia africana (Lam.) Beneth. and Strophanthus hispidus DC.

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.

Antimicrobial and anti-inflammatory activities of pterygota macrocarpa and cola gigantea (sterculiaceae)

Pterygota macrocarpa and Cola gigantea are African medicinal plants used in traditional medicine for the treatment of sores, skin infections, and other inflammatory conditions including pains. This study therefore aims at investigating the antimicrobial properties of ethanol leaf and stem bark extracts of P. macrocarpa and C. gigantea using the agar diffusion and the micro-dilution techniques and also determining the anti-inflammatory properties of the extracts of these plants in carrageenan-induced foot edema in seven-day old chicks. The minimum inhibitory concentration of both ethanol leaf and bark extracts of P. macrocarpa against the test organisms was from 0.125 to 2.55 mg/mL and that of C. gigantea extracts was 0.125 to 2.75 mg/mL. Extracts with concentration of 50 mg/mL were most active against the test organisms according to the agar diffusion method. All the extracts of P. macrocarpa and C. gigantea at 30, 100, and 300 mg/kg body weight except ethanol leaf extract of C. gigantea exhibited significant anti-inflammatory effects (P ≤ 0.001).

Antimicrobial and anti-inflammatory properties of Funtumia elastica

Context: Funtumia elastica (Preuss) Stapf. (Apocynaceae) has a long ethnopharmacological history for uses such as treatment of whooping cough, asthma, blennorhea, painful menstruation, fungal infections, and wounds. Objective: To investigate the antimicrobial and anti-inflammatory properties of ethanol extracts from the leaves and stem bark of Funtumia elastica based on its ethnopharmacological uses and also determine the secondary metabolites present in the extracts. Materials and methods: The antimicrobial activities of ethanol leaf and bark extracts of F. elastica were determined using the microdilution technique (MIC determination) and agar diffusion method using 10, 25, and 50 mg/mL concentrations against Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis, Candida albicans, Aspergillus flavus and Aspergillus niger as test organisms. Anti-inflammatory activities of the doses of extracts at 30, 100, and 300 mg/kg per body weight were determined by carrageenan-induced edema in the footpad of 7-day-old chicks and the foot volumes measured at hourly interval post-treatment for 5 h. Results: The MIC ranges of both ethanol leaf and bark extracts against the test organisms were 125 (lowest MIC) to1550 µg/mL (highest MIC) and 125 (lowest MIC) to 1750 µg/mL (highest MIC), respectively. The ethanol leaf and bark extract of F. elastica showed significant anti-inflammatory activity (p ≤ 0.001) at 30, 100 and 300 mg/kg. Preliminary phytochemical screening revealed that F. elastica bark contains hydrolysable tannins, sapogenetic glycosides, steroids and saponins while the leaves contain hydrolysable tannins, flavonoids, starch and alkaloids. Tannin contents of the leaf and stem bark were 2.4 and 1.3% w/w (related to the dried material), respectively. Discussion and conclusion: Both ethanol leaf and bark extracts of F. elastica showed antimicrobial and anti-inflammatory activities and these pharmacological properties may be responsible for the ethnomedicinal uses of the leaves and stem bark of the plant.

Evaluation of Antimicrobial and Wound Healing Potential of Justicia flava and Lannea welwitschii

Microbial infections of various types of wounds are a challenge to the treatment of wounds and wound healing. The aim of the study is to determine the antimicrobial, antioxidant, and in vivo wound healing properties of methanol leaf extracts of Justicia flava and Lannea welwitschii. The antimicrobial activity was investigated using agar well diffusion and microdilution methods. The free radical scavenging activity of the methanol leaf extracts was performed using 1,1-diphenyl-2-picryl-hydrazyl (DPPH). The rate of wound contraction was determined using excision model. The test organisms used were Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 4853, Bacillus subtilis NTCC 10073, Staphylococcus aureus ATCC 25923, and clinical strains of Candida albicans. The MICs of methanol leaf extract of J. flava against test organisms were E. coli (7.5 mg/mL); P. aeruginosa (7.5 mg/mL); S. aureus (5 mg/mL); B. subtilis (7.5 mg/mL); and C. albicans (5 mg/mL). The MICs of methanol leaf extract of L. welwitschii against test organisms were E. coli (5 mg/mL); P. aeruginosa (10 mg/mL); S. aureus (5 mg/mL); B. subtilis (2.5 mg/mL); and C. albicans (2.5 mg/mL). The MBC/MFC of the extract was between 10 and 50 mg/mL. The IC50 of the reference antioxidant, α-tocopherol, was 1.5 μg/mL and the methanol leaf extracts of J. flava and L. welwitschii had IC50 of 65.3 μg/mL and 81.8 μg/mL, respectively. The methanol leaf extracts of J. flava and L. welwitschii gave a significant reduction in wound size as compared to the untreated. The rates of wound closure after the application of the extracts (7.5% w/w) were compared to the untreated wounds. On the 9th day, J. flava extract had a percentage wound closure of 99% (P < 0.01) and that of L. welwitschii exhibited wound closure of 95% (P < 0.05) on the 13th day compared to the untreated wounds. The two extracts significantly (P < 0.01) increased the tensile strength of wounds compared to the untreated wounds. The extracts treated wound tissues showed improved angiogenesis, collagenation, and reepithelialization compared to the untreated wound tissues. The preliminary phytochemical screening of J. flava and L. welwitschii leaf extracts revealed the presence of tannins, alkaloids, flavonoids, and glycosides. The above results indicate that methanol leaf extracts of J. flava and L. welwitschii possess antimicrobial and wound healing properties which may justify the traditional uses of J. flava and L. welwitschii in the treatment of wounds and infections.

Toxicity assessment of Erythrophleum ivorense and Parquetina nigrescens

Erythrophleum ivorense and Parquetina nigrescens are found growing in tropical regions and they are used in African traditional medicine to treat various ailments including wounds, boils and anaemic conditions. Some species of plant in the Erythrophleum genus are also known to be poisonous and toxic to several livestock. However, there is no information on the toxicity of E. ivorense and P. nigrescens. This study is to determine the cytotoxicity and subchronic toxicity properties of methanol leaf extract (EIML) and methanol stem barks extract (EIMB) of E. ivorense and methanol leaf and aerial part extract of P. nigrescens (PNML). Concentrations from 0.1 to 100 μg/mL of the extracts were used to determine the influence of the extracts on the release of lactate dehydrogenase (LDH) from HaCaT keratinocytes. The EIML and EIMB extracts showed increase in LDH released from HaCaT keratinocytes at 0.1–10 μg/mL and 1–100 μg/mL for the PNML extracts (p > 0.05). Wistar rats were orally administered with 100, 300 and 1000 mg/kg body weight of the extracts (EIML, EIMB and PNML, respectively) for 35 days. Tissues from the kidney and liver of the rats treated with lower doses (100–300 mg/kg body weight) of EIML extract showed highly vascularized kidneys with numerous glomerular tufts, healthy hepatocytes and sinusoids in liver. However, there were persistent renal tissue inflammation and glomerular degeneration in kidney, and increased inflammatory infiltrates with few vacuolations and scarrings in liver in rats treated with higher extract dose of 1000 mg/kg body weight of rat. The rats treated with EIMB extract showed persistent renal and hepatocyte inflammations with glomerular and hepatocyte necrosis at all administered doses (100, 300 and 1000 mg/kg body weight) which are indications of renal and hepatic toxicities. Though rats administered with 100 and 300 mg/kg of PNML extract showed renal haemorrhage and inflammation and hepatic inflammation, the rats administered with 1000 mg/kg body weight showed restoring glomerular tufts and improved vasculature and liver with reduced inflammatory infiltrates with healthy hepatocytes. Phytochemical screening of EIML, EIMB and PNML extracts revealed the presence of alkaloids, tannins, flavonoids, sterols, cardiac glycosides and terpenoids.

Assessment of an ethanolic seed extract of Picralima nitida ([Stapf] Th. and H. Durand) on reproductive hormones and its safety for use.

Background: Picralima nitida seed extract (PNE) has aphrodisiac and contraceptive effect. Aim: To investigate the effect of PNE on reproductive hormones. Materials and Methods: The size and length of the combs of white leghorn day-old chicks treated with testosterone (0.5-1.5 mg/kg), cyproterone (3-30 mg/kg), or PNE (50-500 mg/kg) for 7 days, as well as cyproterone (10, and 30 mg/kg) on PNE-induced, and PNE (50-500 mg/kg) on testosterone-induced comb growth, were measured in the chick comb test. The effect of PNE the percentage change in an oviduct-chick weight ratio of Rhode Island Red layer day-old chicks treated with 17-β-estradiol (0.1-0.9 µg), PNE (30-300 mg/kg) or vehicle, for 6 days, was determined in the chick uterotrophic assay. Liver and kidney function was well lipid, and hematological profile tests were conducted to assess safety. Results: 7-day treatment with PNE and testosterone increased significantly (P ≤ 0.01-0.001) while cyproterone significantly decreased (P ≤ 0.001) comb growth dose-dependently. Qualitatively, testosterone and PNE treatment resulted in relatively brighter red combs. Cyproterone caused significant inhibition (P ≤ 0.001) of both testosterone and PNE-induced comb growth. Co-administration of testosterone and PNE suppressed comb growth significantly (P ≤ 0.001). Administration of 17-β estradiol and PNE increased (P ≤ 0.001) oviduct-chick weight ratio dose-dependently. No significant changes were observed in assessing liver and kidney function, lipid profile, and hematological parameters. Conclusion: PNE exhibits both androgenic (partial testosterone agonist) and estrogenic activity. It has no detrimental effects on the blood, liver, and kidney tissue with prolonged use.