Browsing by Author "Mensah, T."
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Item Bioaccessibility and children health risk assessment of soil-laden heavy metals from school playground and public parks in Accra, Ghana(Springer Link, 2023) Kyene, M.O.; Gbeddy, G.; Mensah, T.; et al.Parks and playground soils constitute a critical matrix for children exposure to hazardous substances due to their high exposure rate. However, minimal investigation has been conducted in Ghana on the subject, thus the need for this research. One hundred and twenty (120) soil samples were collected between April 2015 and March 2016 and then analyzed for heavy metals using atomic absorption spectroscopy. The health risk posed to school children by the heavy metals laden in soil was assessed via oral bioaccessibility and hazard index. The oral bioaccessibility of the metals was estimated using the simple bioaccessibility extraction test (SBET) method. Iron (Fe) measured the highest range of total metal concentrations of 2785.0–15275.0 mg kg−1 followed by Pb of 2.1–284.0 mg kg−1. The oral bioaccessibility of the metals varied significantly with Pb and Cu exhibiting the highest mean values of 47.80% and 54.45%, respectively. The sequence for the mean bioaccessibility result does not correspond with the mean concentration of metals in the soil. The hazard index (HI) for most of the heavy metals indicated no potential non-carcinogenic health risk to children (HI < 1) except for Pb. The prolonged use of leaded fuel in Ghana prior to its outright ban on January 1 2004 and the persistence of Pb in soil media may account for its high risk. The deleterious health effects of Pb on children call for the adoption and implementation of appropriate environmental management of playgrounds so as to mitigate children’s exposure to soil-laden heavy metals.Item Paenidigyamycin G: 1-Acetyl-2,4-dimethyl-3-phenethyl-1H-imidazol-3-ium(molbank, 2019-11-21) Tetevi, G.M.; Kwain, S.; Mensah, T.; Camas, A.S.; Camas, M.; Dofuor, A.K.; Azerigyik, F.A.; Oluwabusola, E.; Deng, H.; Jaspars, M.; Kyeremeh, K.The Ghanaian Paenibacillus sp. DE2SH (GenBank Accession Number: MH091697) is a prolific producer of potent antiparasitic alkaloids. Further detailed study of the culture broth of this strain produced the compound Paenidigyamycin G (1), which is a derivative of the known antiparasitic compound PaenidigyamycinA(2). Compound (1) was isolated on HPLC at tR 37.5 min and its structure determined by IR, UV, MS, 1D, and 2D-NMR data. Compound 1 produced weak to moderate antileishmanial and antitrypanosomal activity when tested against Leishmania donovani (Laveran and Mesnil) Ross (D10) and Trypanosoma brucei subsp. brucei strain GUTat 3.1 with IC50 = 115.41 and 28.75 M, respectively. This result is interesting since the parent compound 2 is known to possess consistent and potent antiparasitic activity. However, 1 displayed a promising selectivity profile towards T. brucei subsp. brucei due to its relatively low toxicity against normal mouse macrophages RAW 264.7 cells (SI = 8.70). Given that compound 1 is also the main metabolite found in the hexane fraction of all extracts produced by Paenibacillus sp. DE2SH when it is co-cultured with other bacteria strains, it must possess some unique biological functions which should make it an excellent candidate for further biological activity screening in other bioassays.Item Synthesis and Characterization of Chrysophyllum albidum (African Star Apple) Plant-Mediated Zinc Oxide Nanostructures and Evaluation of Their Antioxidant, Anti-Inflammatory, and Antimicrobial Activity(Journal of Nanomaterials, 2022) Droepenu, E.K.; Jackson, N.A.N.; Kyene, M.O.; Ayertey, F.; Brew-Daniels, H.; Mensah, T.; Adomako, C.; Nartey, A.P.; Gyampoh, A.O.; Boamah, L.A.This study sought to evaluate the added advantage of mediating ZnO nanostructures with a medicinal plant. The synthesized ZnO nanocrystalline structures were confirmed by Fourier transform infrared spectrometer and characterized through scanning electron microscope, transmission electron microscope, ultraviolet–visible spectroscopy, and energydispersive X-ray spectrometer. The antioxidant, anti-inflammatory, and antimicrobial activities of the ZnO nanostructure mediated with methanol extracts of the leaf, fruit, and seed of Chrysophyllum albidum were then evaluated using DPPH assay, egg albumin denaturation assay, and agar well diffusion methods, respectively. All the characterization analyses revealed high-purity hexagonal-shaped ZnO nanoparticles which were agglomerated. The mean diameter of the particles determined were 11:3±1:7 nm, 20:4±3:2 nm, and 27:3±6:6 nm for C. albidum seed, fruit, and leaf extract-mediated ZnO NPs, respectively. The EC50 values recorded for the antioxidant activity of the extract-mediated ZnO NPs were 0:507 ± 0:015, 0:255 ± 0:006, 0:193 ± 0:003, and 0:004 ± 0:000 mg/mL for leaf, fruit, seed, and ascorbic acid, respectively. From the antimicrobial analysis, C. albidum seed extract-mediated ZnO NPs recorded the highest zone of inhibition (24:33 ± 0:47) against S. aureus whereas C. albidum leaf extract-mediated ZnO NPs gave the lowest zone of inhibition (13:00 ± 1:41) against E. coli at a concentration of 50 mg/mL. Moreover, C. albidum fruit extract-mediated ZnO NPs presented the highest zone of inhibition (18:00 ± 0:82) against the fungus (C. albicans) also at a concentration of 50 mg/mL. The IC50 values recorded for the anti-inflammatory activity of the extract-mediated ZnO NPs showed inhibition in the order fruit > seed > leaf. Meanwhile, extracts of the samples showed the presence of flavonoids, alkaloids, saponins, and glycosides as phytochemical constituents in the leaf, fruit, and seed samples. In conclusion, the synthesized ZnO NPs from the extracts of C. albidum displayed significant antioxidant, anti-inflammatory, and antimicrobial activities against some selected microbes and fungi.