Browsing by Author "Amponsah, Isaac Kingsley"

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    A comparative study of Ghanaian propolis extracts: Chemometric analysis of the chromatographic profile, antioxidant, and hypoglycemic potential and identification of active constituents
    (Scientific African, 2023-11) Amankwaah, Frederick; Addotey, John Nii; Orman, Emmanuel; Adosraku, Reimmel; Amponsah, Isaac Kingsley; 0000-0002-4372-3992
    Diabetes is a disease characterized by high post-prandial glucose levels, which lead to other complications such as peripheral end organ damage. The use of enzyme inhibitors in the management of Type-2 diabetes ensure the control of blood glucose levels via the control of carbohydrate metabolism. The use of standard agents such as acarbose is associated with unwanted side effects hence the need to investigate other sources of antihyperglycemic agents. Propolis, a natural substance from bees, possesses diverse biological activities including antioxidant, antimicrobial and antidiabetic properties. However, the phytochemical content of propolis and its extracts may vary depending on the geographical area, the solvent of extraction and type of bees. This study represents the first attempt to compare different extracts of propolis from the same source in sub-Saharan Africa. In this study, the effect of solvent and source of Ghanaian propolis on parameters such as the total phenolic and flavonoid contents, chromatographic profile, antioxidant and α-amylase inhibitory effects were investigated with the aim of identifying and characterizing the most promising extract, which could be of direct or indirect benefit in the management of Type-2 diabetes. Combinations of water, ethanol-water and ethanol extracts were prepared from propolis from three regions. Phytochemical screening was performed on the extracts after which the Folin Ciocalteu method and aluminum chloride colorimetric assay were used to estimate the total phenolic and flavonoid contents respectively. Antioxidant potential of extracts was estimated using DPPH and phosphomolybdenum assays. In-vitro α-amylase inhibition assay was used to investigate hypoglycemic effect of the extracts. Statistical tools such as ANOVA, principal component analysis, hierarchical cluster analysis employed to determine sources of variations within the data obtained, to classify the extracts based on activity and to predict the most effective extract. This extract was then subjected to UHPLC-Q-TOF MS/MS and GC–MS techniques to characterize the constituents. Chemometric analysis of the data obtained showed that the variations in the data could be explained by both propolis source and extraction solvent. Though ethanol extracts generally contained more constituents, the more notable activities were in the ethanol-water extracts. The ethanol-water extract of Bono East propolis (EWBE) was the most potent DPPH radical scavenger (IC50 of 149.37 ± 2.90 µg/mL as compared to 116.60 ± 0.93 µg/mL GAE standard). It was also one of the three extracts which were more potent than acarbose (369.89 µg/mL) in the α-amylase inhibition assay. The predominant constituents from the LC-MS dereplication of EWBE were caffeic acid and flavonoid derivatives whilst 5,5-dimethyl-1-oxa-5 silacyclononanone-9 was the most significant active constituent identified through the GC–MS analysis. The identified constituents are known to have strong antioxidant and antidiabetic properties. The effects of source and solvent of extraction on the biological and physicochemical properties of propolis in Ghana have been quantified using statistical tools. The combined biological effects of propolis suggest a possible role in their usage in the management of type-2-diabetes and its related complications. Ethanol-water extracts were the most promising with EWBE showing the strongest antihyperglycemic activity. Such extracts represent leads towards further research into toxicity and formulation in order to develop safe and useful products for the management of type-2 diabetes.
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    A formulation of Clausena anisata (Willd.) Hook. f. Ex Benth and Cassia sieberiana DC. alleviates the symptoms associated with osteoarthritis: a single-blind, randomised controlled trial of a traditional Ghanaian remedy
    (Springer Open, 2019) Kwesi Prah, Thomford; Yorke, Joseph; Ama Kyeraa, Thomford; Amponsah, Isaac Kingsley; 0000-0002-5229-0340
    Background: Clinical validation of herbal medicinal products is important for their widespread acceptance and application. In this single-blind, randomised controlled trial, a traditional Ghanaian herbal medicine formulation with Clausena anisata (Willd.) Hook. f. ex Benth and Cassia sieberiana DC. as ingredients was evaluated for its safety and effectiveness in the management of patients with osteoarthritis. The formulation for the purposes of this study was labelled with the code GC-500. Methods: A total of 57 participants were randomly assigned to receive either this herbal remedy, GC-500, or the control treatment of diclofenac. Subjects were then followed up for a period of 8 weeks using a modified Graded Chronic Pain Scale (GCPS) for their efficacy assessments. The control treatment comprised 13 subjects and the GC 500 group 44 subjects. Results: Upon completion of the study, 28 (63.63%) subjects in the GC-500 group attained the primary outcome, (GCPS of Grade 0) compared to 5 (38.46%) subjects in the control group. Improvement in disease indicators such as characteristic pain intensity, disability score and disability days was comparable between the GC-500 and diclofenac. Intensity of pain reduced after 8 weeks of treatment; disability score and disability days also declined indicating an improvement in the quality of life of subjects. GC-500 was also shown to be safe for human use. Conclusion: The herbal medicine formulation GC-500, provides a credible treatment option for managing the pain associated with osteoarthritis.
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    Chemical constituents, anti-inflammatory, anti-oxidant and antimicrobial activities of the stem bark and leaves of Ficus Exasperata (VAHL)
    (2012) Amponsah, Isaac Kingsley
    The work presented in this thesis involves the scientific investigation of the traditional uses of the leaves and stem bark of Ficus exasperata Vahl (Moraceae) as an anti-inflammatory, analgesic and wound healing agent. It also describes the isolation and characterization of the active principles from the Ficus exasperata. The petroleum ether, chloroform, ethyl acetate and 70% ethanolic extracts of the leaves and stem bark were assessed for anti-inflammatory, antioxidant and anti-microbial activities. The anti-inflammatory activities of the extracts and isolates were investigated using the carrageenan – induced foot pad eodema model in seven – day old chicks. The extracts were given orally to the chicks at 30, 100 and 300 mg/kg body weight, 1 hour after induction of oedema with carrageenan. Diclofenac and dexamethasone were used as reference drugs and the foot volume measured by water displacement plethysmography for five hours. All extracts exhibited anti – inflammatory effect with the stem bark showing the highest activity (ED50 = 50.65± 0.012). Antioxidant properties of the extracts were investigated using five assays; total antioxidant capacity, total phenolic content, DPPH scavenging activity, reducing power and lipid peroxidation activity. The most active antioxidant extract was the stem bark with IC50 values of 42.27±0.012, 20.09±0.001 and 61.80±0.001 µg/ml for the lipid peroxidation, DPPH scavenging and reducing power assays. The respective values for the standard antioxidant compound n-propyl gallate were 73.54±0.014, 10.8±0.002 and 66.88±0.002 µg/ml. Antimicrobial evaluation of extracts at concentrations of 10 mg/ ml was done using the agar well diffusion and micro-dilution assays. Seven organisms; P. aeruginosa, S. typhi, K. pneumoniae, E. coli, B. subtlilis, S. aureus and C. albicans were used. The chloroform extract of the stem bark was the most active with MIC of 1000 µg/ml against P. aeruginosa and S. aureus. Bergapten, oxypeucedanin hydrate and sitosterol-3-O-β-D-glucopyranoside were isolated from the bioactive chloroform extract of the stem bark whereas β-sitosterol and sitosterol-3-O-β-D-glucopyranoside were isolated from the pet-ether and ethyl acetate extracts of the leaves. To the best of our knowledge, this is the first report of the isolation of these compounds in Ficus exasperata. They exhibited dose-dependent anti-inflammatory activities with ED50 values of 101.6 ± 0.003, 126.4 ± 0.011, 275.9 ± 0.012 and 123.4 ± 0.033 mg/kg body weight for bergapten, oxypeucedanin hydrate, sitosterol-3-O-β-D-glucopyranoside and β-sitosterol respectively. They also showed significant DPPH scavenging effect with IC50 values of 63.38 ± 0.010, 46.63 ± 0.011, 220.3 ± 0.031 and >1000 µg/ml for the respective compounds. In the antimicrobial assay, β-sitosterol and its glucoside were inactive against all the organisms. Bergapten and oxypeucedanin hydrate gave MIC’s >1000 µg/ml against all susceptible organisms. They were the most active anti-inflammatory, anti-oxidant and antimicrobial compounds. The results of these studies have demonstrated that extracts of the leaves and stem bark of F. exasperata possess anti-inflammatory activity and also display antioxidant and antimicrobial activities. These findings provide scientific justification for the use of the stem bark and leaves of F. exasperata Vahl, in various traditional medicines, for the treatment of inflammatory and infectious conditions.