Browsing by Author "Bayor, Marcel Tunkumgnen"

Now showing 1 - 4 of 4
  • Thumbnail Image
    Item
    The Anticancer and Other Bioacttvity Investigations on the Extract and Some Compounds of Croton Membranaceus [Euphorbiaceae]
    (2007) Bayor, Marcel Tunkumgnen
    Cancer is still responsible for many deaths worldwide. However, cancer prevention is almost impossible due to its numerous aetiological factors. Therefore, the best solution for cancers remains early detection and cure or treatment. Meanwhile, the current treatment options available for cancer including; surgery, radiation therapy, bone marrow transplant and chemotherapy are not only extremely expensive and unaffordable especially for third world countries such as Ghana, but are plagued with treatment failures due to toxic side effects, drug resistance and intolerance. As such the need to search for new, potent, effective, relatively safer, reliable and affordable remedies for the treatment and management of cancer is still paramount. Research into plants has increased in recent years as they have been a source of numerous bioactive compounds including very potent anticancer agents. In Ghana, several plants are used by herbalists and traditional healers for the treatment and/or management of various cancers generally called "kokram" (Twi). However, the efficacies of these plant products as anticancer agents are often ill defined. This « research project therefore, sought to establish a scientific basis for the justification and validation or otherwise of the traditional uses of a selection of Ghanaian medicinal plants in the treatment and management of cancers, and to identify and select suitable candidate(s) for further anticancer investigations and other possible bioactivities including, antimalarial and antimicrobial effects. In this study, the methanolic extracts of ten plant species were evaluated for cytotoxicity and growth inhibitory activities against three human cancer cell lines, DLD-1, MCF-7 and Ml4, using the MTT assay. The extracts of Adenia lobata root, Clerodendrum capitatum leaves, Garcinia kola stem bark, Plumbago zeylanica leaves and Vernonia conferta root, showed relatively low cytotoxic activities (IC50 values above 68 ng/ml), while extracts of Ficus asperifolia leaves, Paullinia pinnata root and Thonningia sanguinea root exhibited moderate activity (IC50 values 40 - 52 fig/ml) against at least one of the three cell lines. Croton membranaceus root extract exhibited markedly higher cytotoxic activities, particularly against the DLD-1 and MCF-7 cells (IC50 = 16.0 and 17.4 (ig/ml, respectively), while Zanthoxylum xanthoxyloides bark extract was 2-3 fold more active against DLD-1 cells (IC50 - 16 jig/ml) than against the other cell lines. These results lent some support for the use of these species, especially C membranaceus and Z xanthoxyloides in traditional medicines for the treatment of cancer and further work on these plants were deemed worthwhile. The bioassay guided fractionation of the methanolic extract of Croton membranaceus root (CMR) revealed that the cytotoxic activity resided mostly in the ethyl acetate fraction. Separation of this fraction using column chromatography resulted in the isolation of six compounds including; a novel furano-clerodane diterpenoid [ 12-oxo-15,16-epoxy- 3,13(16), 14-clerodatrien-17,18-dioic acid dimethyl ester] for which was suggested the trivial name "crotomembranafuran" (1), the glutarimide alkaloid, [2,-N-(2- methylbutanoyO-A^phenylethyl-glutarimide] commonly called julocrotine (2), p- sitosterol (3), p-sitosterol-3-D-glucoside (4), the labdane diterpenoid [labda- 8( 17), 13E-dien-6a, 15-di-O-glucopyranoside] commonly called gomojoside H (5) and DL-butane-1,2,3,4-tetraol (DL-threitol) (6). Apart from julocrotine (2), which has previously been obtained from this plant species, this is the first report of the isolation of compounds 1, 3, 4, 5 and 6 from Croton membranaceus. Three of the compounds, crotomembranafuran (1), p-sitosterol-3-D-glucoside (4) and DL-threitol (6) were active against human prostate cancer (PC-3) cells, with IC50 values of 4.1, 9.7 and 6.6 |j.g/ml, respectively, which indicated that the novel compound (1) was significantly the most active. In the antimalarial testing, p-sitosterol (3), p-sitosterol-3-D-glucoside (4) and DL-threitol (6) exhibited little or no in vitro antiplasmodial activity on Plasmodium falciparum strain 3D7, with IC50 values above 100 pg/ml. However, crotomembranafuran (1), julocrotine (2) and gomojoside H (5) had weak activity giving IC50 values of 43.61, 44.62 and 46.11 ng/ml, respectively. In the antimicrobial investigations, gomojoside H (5) showed significant antimicrobial activity against Staphylococcus aureus, Bacillus subtilis and Pseudomonas aeruginosa, giving minimum inhibitory concentrations (MICs) of less than 10 jig/ml. The other compounds had little or no antimicrobial activity with MICs above 200 µg/ml. The results of the study established that Croton membranaceus root has a number of bioactive compounds including labdane and clerodane type diterpenoids, glutarimide alkaloids and phytosterols. Whilst gomojoside H (5) is a potent antibacterial agent, crotomembranafuran (1) is a novel clerodane diterpenoid with significant cytotoxic (anticancer) properties especially on human prostate cancer (PC-3) cells, and its presence together with the previously known p-sitosterol-3-D-glucoside (4) and DL- threitol (6) could explain, at least in part, the success claimed for the use of the Croton membranaceus root extract in the treatment and management of prostate and other related cancers.  
  • Thumbnail Image
    Item
    The Anticancer and Other Bioactvity Investigations on the Extract and Some Compounds of Croton Membranaceus [Euphorbiaceae]
    (2007) Bayor, Marcel Tunkumgnen
    Cancer is still responsible for many deaths worldwide. However, cancer prevention is almost impossible due to its numerous aetiological factors. Therefore, the best solution for cancers remains early detection and cure or treatment. Meanwhile, the current treatment options available for cancer including; surgery, radiation therapy, bone marrow transplant and chemotherapy are not only extremely expensive and unaffordable especially for third world countries such as Ghana, but are plagued with treatment failures due to toxic, side effects, drug resistance and intolerance. As such the need to search for new, potent, effective, relatively safer, reliable and affordable remedies for the treatment and management of cancer is still paramount. Research into plants has increased in recent years as they have been a source of numerous bioactive compounds including very potent anticancer agents. In Ghana, several plants are used by herbalists and traditional healers for the treatment and/or management of various cancers generally called "kokram" (Twi). However, the efficacies of these plant products as anticancer agents are often ill defined. This research project therefore, sought to establish a scientific basis for the justification and validation or otherwise of the traditional uses of a selection of Ghanaian medicinal plants in the treatment and management of cancers, and to identify and select suitable candidate(s) for further anticancer investigations and other possible bioactivities including, antimalarial and antimicrobial effects. In this study, the methanolic extracts of ten plant species were evaluated for cytotoxicity and growth inhibitory activities against three human cancer cell lines, DLD-1, MCF-7 and Ml4, using the MTT assay. The extracts of Adenia lobata root, Clerodendrum capitatum leaves, Garcinia kola stem bark, Plumbago zeylanica leaves and Vernonia conferta root, showed relatively low cytotoxic activities (IC50 values above 68 ng/ml), while extracts of Ficus asperifolia leaves, Paullinia pinnata root and Thonningia sanguinea root exhibited moderate activity (IC50 values 40 - 52 jig/ml) against at least one of the three cell lines. Croton membranaceus root extract exhibited markedly higher cytotoxic activities, particularly against the DLD-1 and MCF-7 cells (IC50 = 16.0 and 17.4 Hg/ml, respectively), while Zanthoxylum xanthoxyloides bark extract was 2-3 fold more active against DLD-1 cells (IC50 = 16 fig/ml) than against the other cell lines. These results lent some support for the use of these species, especially C. membranaceus and Z xanthoxyloides in traditional medicines for the treatment of cancer and further work on these plants were deemed worthwhile. The bioassay guided fractionation of the methanolic extract of Croton membranaceus root (CMR) revealed that the cytotoxic activity resided mostly in the ethyl acetate fraction. Separation of this fraction using column chromatography resulted in the isolation of six compounds including; a novel furano-clerodane diterpenoid [ 12-oxo-15,16-epoxy- 3,13( 16), 14-clerodatrien-17,18-dioic acid dimethyl ester] for which was suggested the trivial name "crotomembranafuran" (1), the glutarimide alkaloid, [2,-7V-(2- methylbutanoyl)-A^-phenylethyl-glutarimide] commonly called julocrotine (2), p- sitosterol (3), p-sitosterol-3-D-glucoside (4), the labdane diterpenoid [laB&a- 8(17),13E-dien-6a, 15-di-O-glucopyranoside] commonly called gomojoside H (5) and DL-butane-1,2,3,4-tetraol (DL-threitol) (6). Apart from julocrotine (2), which has previously been obtained from this plant species, this is the first report of the isolation of compounds 1, 3, 4, 5 and 6 from Croton membranaceus. Three of the compounds, crotomembranafuran (1), p-sitosterol-3-D-glucoside (4) and DL-threitol (6) were active against human prostate cancer (PC-3) cells, with IC50 values of 4.1, 9.7 and 6.6 jig/ml, respectively, which indicated that the novel compound (1) was significantly the most active. In the antimalarial testing, (3-sitosterol (3), P-sitosterol-3-D-glucoside (4) and DL-threitol (6) exhibited little or no in vitro antiplasmodial activity on Plasmodium falciparum strain 3D7, with IC50 values above 100 fig/ml. However, crotomembranafuran (1), julocrotine (2) and gomojoside H (5) had weak activity giving IC50 values of 43.61, 44.62 and 46.11 jug/ml, respectively. In the antimicrobial investigations, gomojoside H (5) showed significant antimicrobial activity against Staphylococci aureus, Bacillus subtilis and Pseudomonas aeruginosa, giving minimum inhibitory concentrations (MICs) of less than 10 ng/ml. The other compounds had little or no antimicrobial activity with MICs above 200 fig/ml. The results of the study established that Croton membranaceus root has a number of bioactive compounds including labdane and clerodane type diterpenoids, glutarimide alkaloids and phytosterols. Whilst gomojoside H (5) is a potent antibacterial agent, crotomembranafuran (1) is a novel clerodane diterpenoid with significant cytotoxic (anticancer) properties especially on human prostate cancer (PC-3) cells, and its presence together with the previously known P-sitosterol-3-D-glucoside (4) and DL- threitol (6) could explain, at least in part, the success claimed for the use of the Croton membranaceus root extract in the treatment and management of prostate and other related cancers.
  • No Thumbnail Available
    Item
    Pectin from Okra (Abelmoschus esculentus L.) Has Potential as a Drug Release Modifier in Matrix Tablets
    (The Scientific World Journal, 2021) El Boakye-Gyasi, Mariam; Owusu, Frederick William Akuffo; Entsie, Philomena; Agbenorhevi, Jacob K.; Banful, Ben Kwaku Branoh; Bayor, Marcel Tunkumgnen; 0000-0002-8879-230X; 0000-0003-2674-6217; 0000-0002-4858-8339; 0000-0002-8516-7656; 0000-0003-2268-6122; 0000-0002-4170-1140
    Natural polymers have become attractive to pharmaceutical researchers and manufacturers as excipients because of the ad vantages they possess relative to their semisynthetic and synthetic counterparts. Although pectin from some natural sources has been investigated for use in the pharmaceutical industry as excipients, pectin from okra, which is readily available and used as food in many parts of the world, has not been extensively investigated as a potential control-releasing agent in tablets. ,is study thus seeks to determine the drug release modifying properties of okra pectin from 6 different genotypes of okra cultivated and available in Ghana. Pectin was extracted from different genotypes of okra, physicochemical properties were characterized, and control release matrix tablets of metformin (F1–F6) were formulated using the wet granulation method with the okra pectin as the drug release modifier, respectively. ,e drug content, in vitro drug release, and mathematical kinetic modeling of drug release from the matrix tablets were studied. Drug release profiles of formulated matrix tablets were compared to an existing (innovator) brand of metformin sustained-release tablet on the market using the similarity and difference factors, respectively. ,e extracted pectin had percentage yields ranging from 6 to 20% w/w with swelling indexes and water-holding capacities between 300–500% and 9-10 mL/ g, respectively, and pH within 6.20–6.90. All the formulated batches passed the drug content test (90–105%) and produced the optimal release of metformin (>80%) after 24 hours. Different batches of formulated tablets exhibited different mechanisms of drug release with batches F1, F2, F5, and F6 being similar (f 2 values being >50 and f 1 values <15) to the innovator brand. Pectin from the 6 different genotypes of okra studied has the potential for use as drug release modifiers in pharmaceutical manufacturing of control release matrix tablets and production of more affordable medicines.
  • No Thumbnail Available
    Item
    Potential and Comparative Tablet Disintegrant Properties of Pectin Obtained from Five Okra Genotypes in Ghana
    (Hindawi Scientifica, 2021) Owusu, Frederick William Akuffo; Boakye-Gyasi, Mariam El; Agbenorhevi, Jacob K.; Bayor, Marcel Tunkumgnen; Ofori-Kwakye, Kwabena
    Okra pectin has been studied as a potential excipient in tablet formulations for pharmaceutical industries. Okra is widely grown and available in Ghana and other parts of the world. .e prospective use of pectin from okra genotypes grown in Ghana as tablet disintegrants has not been reported. .is study aims to determine the potential and comparative disintegrating properties of pectin from five okra genotypes (Abelmoschus esculentus L.) in Ghana using uncoated immediate release paracetamol tablet formulations. .e yield of the pectin from the various genotypes ranged between 6.12 and 18.84% w/w. .e extracted pectins had pH ranging from slightly acidic to almost neutral (6.39–6.92). Pectin from the various genotypes exhibited good swelling indexes (˃200%), varying solubility in different solvents, and low moisture content (˂20%). Elemental analysis of the extracted pectin from the various genotypes revealed very low levels of toxic metals and micronutrients. Pectin from the various genotypes was evaluated as disintegrants within concentrations of 5–10% w/w (F1–F18). .eir disintegrating properties were compared to that of maize starch BP. All the formulated batches of uncoated immediate release paracetamol tablets (F1–F18) passed the following: uni formity of weight test, uniformity of dimensions, hardness, friability (˂1%), and drug content (95–105%). Significant differences (p ≤ 0.05) were observed between the hardness of the maize starch tablets and tablets formulated from pectin of the various genotypes. Pectin from all genotypes other than PC5 exhibited good disintegrating properties (DT ˂ 15 min) and subsequently passed the dissolution profile test (≥70% release in 45 minutes). Tablets formulated with PC5 as disintegrants at all concentrations (5% w/w (F5), 7.5% w/w (F11), and 10% w/w (F17)) failed the disintegration and dissolution tests. Ultimately, pectins extracted from PC1, PC2, PC3, and PC4 can be commercially exploited as disintegrants in immediate release tablets