Pharmaceutical Microbiology
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Item Antibacterial, antibiofilm activities and toxicity of uvaria chamae P. beauv (annonaceae)(2024) Oluremi, B. B.; Oloche, J. J.; Abiona, P. D.; Ofudi, C. B."Background: Bacteria biofilms are a serious global health concern. The rapid increase of antimicrobial resistance in diarrheagenic bacteria due to biofilm formation has limited the clinical usefulness of some antibiotics in circulation. Objectives: Uvaria chamae has shown broad spectrum antibacterial activity, hence the need to study its antibiofilm activity against enteroaggregative Escherichia coli (EAEC) strains implicated in paediatric diarrhoea. Methods: Samples of authenticated U. chamae root, stem and leaf were collected, air-dried, ground and extracted by cold maceration in dichloromethane and methanol separately. The EAEC strains tested were; O42, DH5α, MN5DE, D25D and D28I. The plant extracts were subjected to quantitative and qualitative phytochemical screening and the 50% lethality (LC50) brine shrimp assay carried out. Extracts were screened for antibacterial activity using agar diffusion method, while agar dilution and broth dilution methods were used to determine minimum inhibitory and bactericidal concentrations, respectively. Biofilm inhibition of the active extracts was investigated by crystal violet method. Results: All the EAEC strains were multi-drug resistant, but susceptible to gentamicin and azithromycin. Dichloromethane leaf extract (DLE) and methanol leaf extract (MLE) inhibited the growth of the tested EAEC strains with the MIC of MLE D28I being MIC 3.75 mg/mL. The percentage biofilm inhibition by MLE against EAEC strains O42, MND5E and D25D were 72%, 74.5%, and 63%, respectively. Alkaloids were the most abundant in the methanol leaf extract of U. chamae (MLE). The extracts had LC50 >1000 μg/mL. Conclusion: Uvaria chamae is non-toxic and possesses antibiofilm potential that could be further developed as a natural remedy for diarrhoea.Item Molecular modeling identification of key secondary metabolites from xylopia aethiopica as promising therapeutics targeting tssential measles viral proteins(Hindawi, 2023-02) Oloche, J. J.; Oluremi, B. B.; Aruwa, C. E.; Sabiu, S.This study computationally screened three key compounds (vanillin (VAN), oxophoebine (OPB), and dihydrochalcone (DHC)) derived from Xylopia aethiopica (Guinea pepper), a medicinal plant with known antiviral activity, against key druggable measles virus (MV) proteins (fusion protein (FUP), haemagglutinin protein (HMG), and phosphoprotein (PSP)). Each molecular species was subjected to a 100 ns molecular dynamics (MD) simulation following docking, and a range of postdynamic parameters including free binding energy and pharmacokinetic properties were determined. The docking scores of the resulting OPB-FUP (-5.4kcal/mol), OPB-HMG (-8.1 kcal/mol), and OPB-PSP (-8.0kcal/mol) complexes were consistent with their respective binding energy values (-25.37, -28.74, and -40.68 kcal/mol), and higher than that of the reference standard, ribavirin (RBV) in each case. Furthermore, all the investigated compounds were thermodynamically compact and stable, especially HMG of MV, and this observation could be attributed to the resulting intermolecular interactions in each system. Overall, OPB may possess inhibitory properties against MV glycoproteins (FUP and HMG) and PSP that play important roles in the replication of MV and measles pathogenesis. While OPB could serve as a scaffold for the development of novel MV fusion and entry inhibitors, further in vitro and in vivo evaluation is highly recommended.Item In vitro inhibition of multi-drug resistant pseudomonas efflux pump by xylopia aethiopica (dunal) A. rich(African Research Opinion Communication (AROC), 2021-09) Oloche, J. J.; Oluremi, B. B.; Koya, T. O.Global health is under constant threat due to antimicrobial drug resistance. Bacterial Infections caused by Pseudomonas aeruginosa are of importance because of their antibiotics resistance. This study aimed at evaluating the effects of extracts of Xylopia aethiopica (XA) on multidrug-resistant (MDR) Pseudomonas isolates. Fresh samples of XA leaf, stem bark and roots were collected from the botanical garden, University of Ibadan, Nigeria. Dried and pulverized samples were extracted with methanol and partitioned into n-hexane, dichloromethane and ethyl acetate. Phytochemical screening of the extracts was performed by standard methods. Antimicrobial activity and synergistic interaction were determined using microdilution and checkerboard broth dilution methods, respectively. The results revealed that crude methanol extracts of XA leaf, stem bark and root significantly (p<0.05) inhibited the growth of all tested MDR Pseudomonas isolates at 10 mg/mL. At 1 mg/mL, the ethyl acetate fraction of the leaf, and dichloromethane fraction of the roots produced clear zones of inhibition of 12 – 20 mm, and minimum inhibitory concentrations (MICs) of 1 μg/mL and 0.5 mg/mL, respectively. The modulation factor (MF) of ciprofloxacin, dichloromethane fraction of XA roots and ethyl acetate fraction of XA leaf were 4, 8, and 4 on MDR isolates E01006, OAU058 and P. aeruginosa ATCC 27853, respectively. In all tested isolates, but not E01006 and E01024, the fractional MICs of ciprofloxacin/ethylacetate fraction of XA leaf extract combination was not significantly different (p>0.05) compared with ciprofloxacin/verapamil combination. In conclusion, the root and leaf fractions Xylopia aethiopica that demonstrated antimicrobial activity against MDR P. aeruginosa and synergised with ciprofloxacin have the potential to rejuvenate the antimicrobial activity of ciprofloxacin in MDR P. aeruginosa.Item Anticancer and antibacterial activities of solanum aethiopicum L., solanum macrocarpon L. and garcinia kola heckel(2021-05) Oluremi, B. B.; Oloche, J. J.; Aden, A. J.Cancer and infectious diseases are among the top ten leading causes of death in developing countries. The discovery and development of newer agents for combating these global health problems cannot be overemphasized. This study was designed to investigate the activities of extracts of Solanum aethiopicum, Solanum macrocarpon and Garcinia kola on cancer and antibacterial pathogens. The Agar well diffusion method was used to evaluate antibacterial activity of the extracts. In vitro anticancer activity against cervical cancer (HeLa), breast cancer (MCF-7) and epidermoid carcinoma of the larynx (HEp-2) was done by microscopic evaluation of morphology and by determination of 50% cytotoxic concentrations (CC50). The CC50 of ethyl acetate extracts of Solanum aethiopicum and Solanum macrocarpon against MCF-7 were 38.79 μg/mL and 41.30 μg/mL respectively, and were significantly lower (p < 0.05) compared to the CC50 of the other extracts. Dichloromethane extract of Garcinia kola was significantly cytotoxic (p<0.05) on cervical cancer (CC50 = 38.13 μg/mL) compared to DCM extracts from Solanum aethiopicum and Solanum macrocarpon. The minimum concentration of methanol extracts of Solanum aethiopicum, Solanum macrocarpon and Garcinia kola that inhibited the growth of Staphylococcus aureus, Pseudomonas aeruginosa, Escherichia coli and Klebsiella pneumoniae was 1.56 mg/mL. Solanum aethiopicum, Solanum macrocarpon and Garcinia kola extracts demonstrated significant (p < 0.05) anticancer and antibacterial activities and as such are promising sources of novel plant-derived anticancer and antibacterial drugs.Item Evaluation of phytochemical constituents and antimicrobial activity of leaves and stem bark extracts of sarcocephalus latifolius(2018) Oluremi, B.; Oloche, J. J.; Fasusi, E. T.; Lawal, A. M.Sarcocephalus latifolius is reported to have a wide range of medicinal properties and it is commonly used in the treatment of malaria, hypertension, diarrhea, dysentery and dental problems. Considering its characteristics, it is important to identify the phytochemical constituents and further evaluate the antimicrobial activity. Thus, this study was designed to identify the phytochemical constituents and to evaluate the antimicrobial activity of the leaf and stem bark extracts of Sarcocephalus latifolius on bacteria strains isolated from dental samples. The phytochemical compounds in leaf and stem bark extracts of Sarcocephalus latifolius were analyzed using GC-QPMS. The mixture of bioactive compounds present in leaf and stem extracts of Sarcocephalus latifolius were tested against Gram-positive and Gram-negative bacteria for inhibition of growth using agar-cup-diffusion method. Results emerging from this study show that a total of 19 compounds and 25 compounds were identified from the leaf and stem bark extracts respectively. Decanoic acid, decanoic acid, benzene carboxylic acid and terpenes; phytol and farnesyl acetatewere identified to be the main constituents. Furthermore, the extracts at concentrations of 25-50 mg/ml inhibited the growth of bacteria isolates in a manner that is comparable to the standard antibiotic (p<0.05). The significant zones of inhibition of bacterial growth by leaf and stem extracts of Sarcocephalus latifolius validates the use of extracts of Sarcocephalus latifolius in traditional medicine and as a promising source of antimicrobial agents.Item Suboptimal bacteriological quality of household water in municipal Ibadan, Nigeria(2024) Alabi, O. S.; Akintayo, I.; Odeyemi, J. S.; Oloche, J. J.; Babalola, C. M.; Nwimo, C.; Popoola, O.; Mogeni, O. D.; Marks, F.; Okeke, I. N.Access to potable water is difficult for many African residents. This study evaluated the bacteriological quality of household water collected in the dry and wet seasons across five municipal local government areas (LGAs) in Ibadan, a large city in southwest Nigeria. A total of 447 water samples (dry season, n 5 250; wet season, n 5 197) were aseptically collected from a random sample of mapped households within Ibadan’s five municipal LGAs. The pH values and total aerobic and coliform bacterial counts were measured, and samples were screened for Escherichia coli, Salmonella, Shigella, and Yersinia by standard phenotypic techniques and multiplex polymerase chain reaction. The most common source of water was well (53.2%), followed by borehole (34%). None of the households used municipal tap water. Cumulatively, aerobic (P 5 0.0002) and coliform (P 5 0.0001) counts as well as pH values (P 5 0.0002) changed significantly between seasons, with increasing and decreasing counts depending on the LGA. Nonpotable water samples were found to be very common during the dry (86.8%) and wet (74.1%) seasons. Escherichia coli spp., as indicators of recent fecal contamination, were isolated from 115 (25.7%) of the household water sources. Thirty three Salmonella, four enteroaggregative E. coli, and four enterotoxigenic E. coli isolates but no Shigella or Yersinia isolates were identified. This study revealed the absence of treated tap water and the poor quality of alternative sources with detectable pathogens in municipal Ibadan. Addressing the city-wide lack of access to potable water is an essential priority for preventing a high prevalence of feco-orally transmitted infections.