Browsing by Author "Adegle, R."
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Item Anti-plasmodial, Cytotoxic and Antioxidant Activities of Selected Ghanaian Medicinal Plants(SAGE, 2022) Appiah-Opong, R.; Agyemang, K.; Dotse, E.; Atchoglo, P.; Owusu, K.B.; Aning, A.; Sakyiamah, M.; Adegle, R.; Ayertey, F.; Appiah, A.A.; Nyarko, A.K.Malaria affects about half of the world’s population. The sub-Saharan African region is the most affected. Plant natural products have been a major source of antimalarial drugs; the first (quinine) and present (artemisinin) antimalarials are of natural product origin. Some secondary metabolites demonstrate adjuvant antioxidant effects and selective activity. The focus of this study was to investigate the anti-plasmodial activity, cytotoxicities and antioxidant properties of eight (8) Ghanaian medicinal plants. The anti-plasmodial activity was determined using the SYBR green assay and the tetrazolium-based colorimetric assay (MTT) was employed to assess cytotoxicity of extracts to human RBCs and HL-60 cells. Antioxidant potential of plant extracts was evaluated using Folin-Ciocalteu and superoxide dismutase assays. Phytochemical contstituents of the plant extracts were also assessed. All the extracts demonstrated anti-plasmodial activities at concentrations <50 μg/ml. Parkia clappertoniana and Terminalia ivorensis elicited the strongest anti-plasmodial activities with 50% inhibitory concentrations (IC50) of 1.13 μg/ml and 0.95 μg/ml, respectively. This is the first report on anti-plasmodial activities of Baphia nitida, Tabernaemontana crassa and Treculia Africana. T. Africana showed moderate anti-plasmodial activity with IC50 value of 6.62 µg/mL. Extracts of P. clappertoniana, T. Africana and T. ivorensis (0.4 mg/mL) showed >50% antioxidant effect (SOD). The extracts were not cytotoxicity towards RBCs at the concentration tested (200 μg/ml) but were weakly cytotoxic to HL-60 cell. Selectivity indices of most of the extracts were greater than 10. Our results suggest that most of the plant extracts have strong anti-plasmodial activity and antioxidant activity which warrants further investigations.Item Anti-plasmodial, Cytotoxic and Antioxidant Activities of Selected Ghanaian Medicinal Plants(SAGE, 2022) Appiah-Opong, R.; Agyemang, K.; Dotse, E.; Atchoglo, P.; Owusu, K.B.; Aning, A.; Sakyiamah, M.; Adegle, R.; Ayertey, F.; Appiah, A.A.; Nyarko, A.K.Malaria affects about half of the world’s population. The sub-Saharan African region is the most affected. Plant natural products have been a major source of antimalarial drugs; the first (quinine) and present (artemisinin) antimalarials are of natural product origin. Some secondary metabolites demonstrate adjuvant antioxidant effects and selective activity. The focus of this study was to investigate the anti-plasmodial activity, cytotoxicities and antioxidant properties of eight (8) Ghanaian medicinal plants. The anti-plasmodial activity was determined using the SYBR green assay and the tetrazolium-based colorimetric assay (MTT) was employed to assess cytotoxicity of extracts to human RBCs and HL-60 cells. Antioxidant potential of plant extracts was evaluated using Folin-Ciocalteu and superoxide dismutase assays. Phytochemical contstituents of the plant extracts were also assessed. All the extracts demonstrated anti-plasmodial activities at concentrations <50 μg/ml. Parkia clappertoniana and Terminalia ivorensis elicited the strongest anti-plasmodial activities with 50% inhibitory concentrations (IC50) of 1.13 μg/ml and 0.95 μg/ml, respectively. This is the first report on anti-plasmodial activities of Baphia nitida, Tabernaemontana crassa and Treculia Africana. T. Africana showed moderate anti-plasmodial activity with IC50 value of 6.62 μg/mL. Extracts of P. clappertoniana, T. Africana and T. ivorensis (0.4 mg/mL) showed >50% antioxidant effect (SOD). The extracts were not cytotoxicity towards RBCs at the concentration tested (200 μg/ml) but were weakly cytotoxic to HL-60 cell. Selectivity indices of most of the extracts were greater than 10. Our results suggest that most of the plant extracts have strong anti-plasmodial activity and antioxidant activity which warrants further investigations.Item Determination of the absolute configuration of the novel anti-trypanosomal iridoid molucidin isolated from Morinda lucida by X-ray analysis(ELSEVIER, 2015-12) Karasawa, S.; Yoza, K.; Tung, N.H.; Uto, T.; Morinaga, O.; Suzuki, M.; Kwofie, K.D.; Amoa-Bosompem, M.; Boakye, D.A.; Ayi, I.; Adegle, R.; Sakyiamah, M.; Ayertey, F.; Aboagye, F.; Appiah, A.A.; Owusu, K.B.-A.; Tuffour, I.; Atchoglo, P.; Shoyama, Y.The strong anti-trypanosomal active compound, molucidin, contains a spirolactone tetracyclic iridoid skeleton and is isolated from Morinda lucida as an enantiomer of oruwacin, which is isolated from the same plant. To confirm the absolute configuration of molucidin, we prepared single crystals of molucidin for X-ray analysis. The absolute configuration of the afforded single crystal was determined by X-ray crystallography using a Cu radiation source. X-ray diffraction data were collected at 93 K in the 2θ range 7.468–134.99° and analyzed using the SHELXL-2014 program. The corresponding chiral quaternary carbon atoms in molucidin were unambiguously determined as 1R, 5S, 8S, 9S, and 10S. Notably, both enantiomers of a single molecule, molucidin and oruwacin, with a rigid structure have been isolated from the same plant species. The biosynthetic pathway for the formation of molucidin is also discussed on the basis of the absolute configuration. Our results for the first time support for structural elucidation of tetracyclic iridoids using X-ray analysis.Item In vitro antiprotozoan activity and mechanisms of action of selected Ghanaian medicinal plants against Trypanosoma, Leishmania, and Plasmodium parasites(Phytotherapy Research, 2018-08) Ohashi, M.; Amoa-Bosompem, M.; Kwofie, K.D.; Agyapong, J.; Adegle, R.; Sakyiamah, M.M.; Ayertey, F.; Owusu, K.B.A.; Tuffour, I.; Atchoglo, P.et.al.Trypanosomiasis, leishmaniasis, and malaria are protozoan infections of public health importance with thousands of new cases recorded annually. Control of these infection(s) with existing chemotherapy is limited by drug toxicity, lengthy parenteral treatment, affordability, and/or the emergence of resistant strains. Medicinal plants on the other hand are used in the treatment of various infectious diseases although their chemical properties are not fully evaluated. In this study, we screened 112 crude extracts from 72 selected Ghanaian medicinal plants for anti-Trypanosoma, anti-Leishmania, and anti-Plasmodium activities in vitro and investigated their mechanisms of action. Twenty-three extracts from 20 plants showed significant antiprotozoan activity against at least 1 of 3 protozoan parasites screened with IC50 values less than 20 μg/ml. Eleven extracts showed high anti-Trypanosoma activity with Bidens pilosa whole plant and Morinda lucida leaf extracts recording the highest activities. Their IC50 (selectivity index [SI]) values were 5.51 μg/ml (35.00) and 5.96 μg/ml (13.09), respectively. Nine extracts had high anti-Leishmania activity with Annona senegalensis and Cassia alata leaf extracts as the most active. Their IC50 (SI) values were 10.8 μg/ml (1.50) and 10.1 μg/ml (0.37), respectively. Six extracts had high anti-Plasmodium activity with the leaf and stem-bark extracts of Terminalia ivorensis recording the highest activity. Their IC50 (SI) values were 7.26 μg/ml (129.36) and 17.45 μg/ml (17.17), respectively. Only M. lucida at 25 μg/ml induced significant apoptosis-like cell death in Trypanosoma parasites. Anti-Leishmania active extracts induced varying morphological changes in Leishmania parasites such as multiple nuclei and/or kinetoplast, incomplete flagella division, or nuclear fragmentation. Active extracts may be potential sources for developing new chemotherapy against these infections.Item New anti-trypanosomal active tetracyclic iridoid isolated from Morinda lucida Benth.(Bioorganic & Medicinal Chemistry Letters, 2015-08) Suzuki, M.; Tung, N.H.; Kwofie, K.D.; Adegle, R.; Amoa-Bosompem, M.; Sakyiamah, M.; Ayertey, F.; Owusu, K.B.-A.; Tuffour, I.; Atchoglo, P.; Frempong, K.K.; Anyan, W.K.; Uto, T.; Morinaga, O.; Yamashita, T.; Aboagye, F.; Appiah, A.A.; Appiah-Opong, R.; Nyarko, A.K.; Yamaoka, S.; Yamaguchi, Y.; Edoh, D.; Koram, K.; Ohta, N.; Boakye, D.A.; Ayi, I.; Shoyama, Y.Human African trypanosomiasis (HAT), commonly known as sleeping sickness has remained a serious health problem in many African countries with thousands of new infected cases annually. Chemotherapy, which is the main form of control against HAT has been characterized lately by the viewpoints of toxicity and drug resistance issues. Recently, there have been a lot of emphases on the use of medicinal plants world-wide. Morinda lucida Benth. is one of the most popular medicinal plants widely distributed in Africa and several groups have reported on its anti-protozoa activities. In this study, we have isolated one novel tetracyclic iridoid, named as molucidin, from the CHCl3 fraction of the M. lucida leaves by bioassay-guided fractionation and purification. Molucidin was structurally elucidated by 1H and 13C NMR including HMQC, HMBC, H–H COSY and NOESY resulting in tetracyclic iridoid skeleton, and its absolute configuration was determined. We have further demonstrated that molucidin presented a strong anti-trypanosomal activity, indicating an IC50 value of 1.27 μM. The cytotoxicity study using human normal and cancer cell lines indicated that molucidin exhibited selectivity index (SI) against two normal fibroblasts greater than 4.73. Furthermore, structure–activity relationship (SAR) study was undertaken with molucidin and oregonin, which is identical to anti-trypanosomal active components of Alnus japonica. Overlapping analysis of the lowest energy conformation of molucidin with oregonin suggested a certain similarities of aromatic rings of both oregonin and molucidin. These results contribute to the future drug design studies for HAT.Item Procyanidin trimer C1 derived from Theobroma cacao reactivates latent human immunodeficiency virus type 1 provirus.(Biochemical and Biophysical Research Communications, 2015-04) Hori, T.; Barnor, J.; Nguyen Huu, T.; Morinaga, O.; Hamano, A.; Ndzinu, J.; Frimpong, A.; Minta-Asare, K.; Amoa-Bosompem, M.; Brandful, J.; Odoom, J.; Bonney, J.; Tuffour, I.; Owusu, B.-A.; Ofosuhene, M.; Atchoglo, P.; Sakyiamah, M.; Adegle, R.; Appiah-Opong, R.; Ampofo, W.; Koram, K.; Nyarko, A.; Okine, L.; Edoh, D.; Appiah, A.; Uto, T.; Yoshinaka, Y.; Uota, S.; Shoyama, Y.; Yamaoka, S.Despite remarkable advances in combination antiretroviral therapy (cART), human immunodeficiency virus type 1 (HIV-1) infection remains incurable due to the incomplete elimination of the replication-competent virus, which persists in latent reservoirs. Strategies for targeting HIV reservoirs for eradication that involves reactivation of latent proviruses while protecting uninfected cells by cART are urgently needed for cure of HIV infection. We screened medicinal plant extracts for compounds that could reactivate the latent HIV-1 provirus and identified a procyanidin trimer C1 derived from Theobroma cacao as a potent activator of the provirus in human T cells latently infected with HIV-1. This reactivation largely depends on the NF-κB and MAPK signaling pathways because either overexpression of a super-repressor form of IκBα or pretreatment with a MEK inhibitor U0126 diminished provirus reactivation by C1. A pan-PKC inhibitor significantly blocked the phorbol ester-induced but not the C1-induced HIV-1 reactivation. Although C1-induced viral gene expression persisted for as long as 48 h post-stimulation, NF-κB-dependent transcription peaked at 12 h post-stimulation and then quickly declined, suggesting Tat-mediated self-sustainment of HIV-1 expression. These results suggest that procyanidin C1 trimer is a potential compound for reactivation of latent HIV-1 reservoirs.