Yaw Duah Boakye

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.

Review: African medicinal plants with wound healing properties

ETHNOPHARMACOLOGICAL RELEVANCE Wounds of various types including injuries, cuts, pressure, burns, diabetic, gastric and duodenal ulcers continue to have severe socio-economic impact on the cost of health care to patients, family and health care institutions in both developing and developed countries. However, most people in the developing countries, especially Africa, depend on herbal remedies for effective treatment of wounds. Various in vitro and in vivo parameters are used for the evaluation of the functional activity of medicinal plants by using extracts, fractions and isolated compounds. The aim of the review is to identify African medicinal plants with wound healing properties within the last two decades. MATERIALS AND METHODS Electronic databases such as PubMed, Scifinder(®) and Google Scholar were used to search and filter for African medicinal plants with wound healing activity. The methods employed in the evaluation of wound healing activity of these African medicinal plants comprise both in vivo and in vitro models. In vivo wound models such as excision, incision, dead space and burn wound model are commonly employed in assessing the rate of wound closure (contraction), tensile strength or breaking strength determination, antioxidant and antimicrobial activities, hydroxyproline content assay and histological investigations including epithelialisation, collagen synthesis, and granulation tissue formation. In in vitro studies, single cell systems are mostly used to study proliferation and differentiation of dermal fibroblasts and keratinocytes by monitoring typical differentiation markers like collagen and keratin. RESULTS In this study, 61 plants belonging to 36 families with scientifically demonstrated or reported wound healing properties were reviewed. Various plant parts including leaves, fruits, stem bark and root extracts of the plants are used in the evaluation of plants for wound healing activities. CONCLUSION Although, a variety of medicinal plants for wound healing can be found in literature, there is a need for the isolation and characterization of the bioactive compounds responsible for the wound healing properties. Also, cytotoxicity studies should be performed on the promising agents or bioactive fractions or extracts.

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.

Anti-inflammatory activity of aqueous leaf extract of Phyllanthus muellerianus (Kuntze) Exell. and its major constituent, geraniin

ETHNOPHARMACOLOGICAL RELEVANCE Phyllanthus muellerianus (Kuntze) Exell. which belongs to the Family Euphorbiaceae is a shrub widely distributed in West Africa. It is used traditionally to manage wounds and wound infections, menstrual disorders, fevers, pain and inflammation. Hence to confirm its ethnobotanical uses in managing inflammation, we investigated the anti-inflammatory properties of aqueous leaf extract of P. muellerianus (PLE) and its major isolate, geraniin in experimentally-induced inflammation in rats. MATERIALS AND METHODS Carrageenan induced oedema and adjuvant induced arthritis models in rats were used in this study. RESULTS In the carrageenan-induced acute inflammation, both 300mg/kg PLE-treated and 10mg/kg geraniin-treated groups significantly reduced the mean maximal swelling attained at 4h to 46.75±4.97% (p<0.01) and 61.65±6.70% (p<0.05), respectively, from the inflamed control response of 122.60±16.39%. In the adjuvant-induced chronic inflammation, both PLE-treated (100 and 300mg/kg) groups and geraniin-treated (10 and 30mg/kg) groups significantly (p<0.001) reduced the total limb swelling over 16 days in the polyarthritic phase compared to the arthritic control. These observations were supported by the radiograph records and the histological investigations of the hind limbs which showed reduced bone damage in both PLE and geraniin-treated rats. CONCLUSION The findings may confirm the ethnobotanical use of PLE in the management of inflammatory disorders or conditions and observed anti-inflammatory property of PLE may largely be due to its major constituent, geraniin.

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.

Wound Healing and Anti-Infective Properties of Myrianthus arboreus and Alchornea cordifolia

Myrianthus arboreus P. Beauv. (Cecropiaceae) and Alchornea cordifolia (Schum. & Thonn.) Muel. Arg. (Euphorbiaceae) are tropical plants used for the treatment of ailments such as diarrhoea, malaria, boils, dysentery, wounds and skin infections. The study investigated the antimicrobial, antioxidant and wound healing properties of methanol leaf extract of M. arboreus (MLMA), aqueous (AqLAC) and ethanol leaf extracts (ELAC) of A. cordifolia. The antimicrobial activity of the extracts was examined using the agar diffusion and micro-dilution methods against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 4853, Staphylococcus aureus ATCC 25923, Bacillus subtilis NTCC 10073 and clinical strain of Candida albicans. Antioxidant property of the extracts was determined by DPPH method and wound healing property of the extracts determined using excision wound model. MLMA exhibited activity against S. aureus, B.subtilis, E. coli, P. aeruginosa and C. albicans with MIC values of 8.0, 6.0, 8.0, 10.0 and 6.0 mg/mL, respectively. ELAC showed good antimicrobial activity against S. aureus, B.subtilis, E. coli, P. aeruginosa and C. albicans with MICs of 3.0, 4.0, 6.0, 4.0 and 4.0 mg/mL respectively; and AqACL had MICs of 2.5, 3.0, 10.0, 4.0 and 3.0 mg/mL, respectively. The IC 50 of MLMA, AqACL and ELAC were 2.68, 0.79, 0.78 µg/mL respectively. The extracts (5% w/w AqACL and 10% w/w MMAL extract creams) showed potent wound healing capacity with better wound closure (p<0.05) at day 1 and day 9 (p<0.001) compared with untreated wounds. Histological investigations showed enhanced wound tissue proliferation, fibrosis and re-epithelization compared with the untreated wound tissues. Phytochemical screening of extracts revealed the presence of tannins, alkaloids, glycosides, terpenoids and flavonoids. The biological activities of the extracts from the two plants may justify their uses in treatment for microbial infections and wounds.

In vitro Activity and Evaluation of Quality of Some Selected Penicillins on the Ghanaian Market using Developed HPLC Methods

The use of antibiotics in health delivery is inevitable since it is one of the most prescribed medications. The quality and efficacy of these medications are crucial in health systems since they can affect the quality of healthcare delivery. The study was designed to determine the quality and activity of some penicillins on the Ghanaian market. A total of 54 samples (29 capsules and 25 suspensions) of different brands and batches were collected from different pharmacies in Accra and Kumasi, Ghana, from October 2011 to May 2012. The activity (zones of inhibition) and minimum inhibitory concentration (MIC) of the samples were determined by the agar-well diffusion and micro-dilution methods respectively against two typed strains of Gram-negative and Gram-positive bacteria. Quality of the samples was determined quantitatively by developed and validated HPLC methods. The MICs of flucloxacillin and cloxacillin samples were ≥ 1400 µg/mL, whiles that of amoxicillin samples were ≥ 200 µg/mL, with reference to the standard antibiotics which gave MICs of 200 to 800 µg/mL against all the test bacteria with the suspensions exhibiting higher antimicrobial activity. Specificity, linearity, precision and accuracy of the developed HPLC method were determined. HPLC analysis of the samples revealed that 75% of amoxicillin capsule samples and 92.3% of amoxicillin suspension samples contained the right amount of active pharmaceutical ingredient (API) with percentages ranging from 93.2 to 104.3% and 81.0 to 104.1% respectively. For samples of flucloxacillin capsules, 62.5% of the samples showed API content from 96 to 120.5%. All the suspension samples have their API within BP and USP specification of 114.4 to 120.0%. Capsules (58.6%) of all the samples contained the right API whereas 64% of them were recorded for suspensions. Out of the 54 samples evaluated, 61.1% were within the BP and USP specifications. The biological assay revealed higher MIC values for all the penicillin samples evaluated compared with the reference samples. Among the samples evaluated, amoxicillin showed better quality of 82.8% as compared to flucloxacillin (31.3%) and cloxacillin (44.4%) samples. Efforts should therefore be made to improve the quality and storage conditions of these antibiotics and also constant monitoring and surveillance of activity and potency of these antibiotics should be done.

Anti-Inflammatory and Analgesic Activities of African Medicinal Plants

Over a long period of time, several medicinal plants have been used for the treatment and management of various forms of inflammatory conditions by African traditional healers and herbalists. But most of these plants are not documented as compared to the Chinese or Indian (Ayurveda) traditional medicines. About 5000 plant species have been used for centuries for the treatment of various diseases, including inflammatory diseases, and as food. A few African medicinal plants with demonstrated anti-inflammatory and analgesic properties have been documented in the last two decades. This chapter reviews such plant species and their extracts, fractions, and compounds that have been shown to exhibit experimental or clinical anti-inflammatory or analgesic activity, the possible mechanism of action, and their therapeutic value. In the current review, we identify 50 African medicinal plants belonging to 33 families having anti-inflammatory and analgesic properties in the literature over the last 20 years. Two pure compounds, namely pseudo-akuammigine, from the seeds of Picralima nitida (Stapf) T. Durand & H. Durand, and leonotinin, isolated from the aerial parts of Leonotis nepetaefolia (L.) W.T. Aiton, have been found to possess anti-inflammatory properties.

Anti-infective Properties and Time-Kill Kinetics of Phyllanthusmuellerianus and its Major Constituent, Geraniin

Microbial resistance to existing antimicrobial agents remains a global challenge. In recent years, there has been a significant upsurge in the search for newer antimicrobial agents from nature with plants becoming the major focus in most parts of the world due to the vast availability of plants, which have not been screened for their antimicrobial activity. Hence, the study investigates the antimicrobial properties of aqueous aerial part extract of Phyllanthus muellerianus (PLE) and its major constituent, geraniin. The agar well diffusion and micro-dilution methods as well as time-kill kinetic studies were used to determine the antimicrobial activity of PLE and geraniin against Escherichia coli ATCC 25922, Pseudomonas aeruginosa ATCC 27853, Staphylococcus aureus ATCC 25923, Bacillus subtilis NCTC 10073, Streptococcus pyogenes (clinical isolate) and Candida albicans (clinical isolate). The mean zones of growth inhibition for PLE and geraniin were in the range of 12.0 ± 0.0 to 22.7 ± 0.3 and 12.0 ± 0.0 to 21.6 ± 0.3 mm, respectively. MIC of both PLE and geraniin ranged from 0.31 to 5 and 0.08 to 1.25 mg/mL (90 to 1310 μM), respectively whiles the minimum cidal concentrations were 5.0 to 50.0 and 2.5 to 10 mg/mL (2.62 to 10.5 mM), respectively. The time-kill kinetics study showed that PLE and geraniin may act as microbiostatic agents. Preliminary phytochemical screening of PLE showed the presence of alkaloids, glycosides, saponins, tannins, flavonoids and terpenoids. The observed antimicrobial activity of the extract, PLE, may be due in large proportion to its major constituent, geraniin.

Antimicrobial Activities and Time-Kill Kinetics of Extracts of Selected Ghanaian Mushrooms

The rapid rise of antimicrobial resistance is a worldwide problem. This has necessitated the need to search for new antimicrobial agents. Mushrooms are rich sources of potential antimicrobial agents. This study investigated the antimicrobial properties of methanol extracts of Trametes gibbosa, Trametes elegans, Schizophyllum commune, and Volvariella volvacea. Agar well diffusion, broth microdilution, and time-kill kinetic assays were used to determine the antimicrobial activity of the extracts against selected test organisms. Preliminary mycochemical screening revealed the presence of tannins, flavonoids, triterpenoids, anthraquinones, and alkaloids in the extracts. Methanol extracts of T. gibbosa, T. elegans, S. commune, and V. volvacea showed mean zone of growth inhibition of 10.00 ± 0.0 to 21.50 ± 0.84, 10.00 ± 0.0 to 22.00 ± 1.10, 9.00 ± 0.63 to 21.83 ± 1.17, and 12.00 ± 0.0 to 21.17 ± 1.00 mm, respectively. The minimum inhibitory concentration of methanol extracts of T. gibbosa, T. elegans, S. commune, and V. volvacea ranged from 4.0 to 20, 6.0 to 30.0, 8.0 to 10.0, and 6.0 to 20.0 mg/mL, respectively. Time-kill kinetics studies showed that the extracts possess bacteriostatic action. Methanol extracts of T. gibbosa, T. elegans, S. commune, and V. volvacea exhibited antimicrobial activity and may contain bioactive compounds which may serve as potential antibacterial and antifungal agents.