Paul Keilah Lunga

Background: In endemic countries, people remain at risk of contracting both malaria and typhoid concurrently. Though experimental animal models are very reliable for understanding human diseases, the rat model for Plasmodium–Salmonella coinfection remains underresearched. Objectives: The present study was performed to characterize the rat model of malaria–typhoid coinfection focusing on physical, hematological, and biochemical parameters. Methods: Thirty‐four Wistar rats were distributed into five groups including normal control, immunosuppressed, Salmonella ‐infected, Plasmodium ‐infected, and Salmonella–Plasmodium ‐coinfected. Physical signs, mobility, and the fecal appearance of animals were observed. Plasmodium load was monitored through microscopic Giemsa‐staining thin blood smears. Concurrently, Salmonella load was evaluated after feces culture in Shigella–Salmonella agar medium based on the McFarland turbidity to determine the number of colony‐forming units. Hematological and biochemical parameters were assessed using an automatic hematology analyzer and a spectrophotometer, respectively. Results: All the infected animals exhibited at least one clinical sign including piloerection, eye depigmentation, or hyperthermia. Coinfected animals showed severe anemia, leukocytosis, and thrombocytosis compared with monoinfected animals. A significant ( p < 0.001) drop in total blood proteins and cholesterol levels was observed in infected rats, with a remarkable decrease in Salmonella–Plasmodium ‐coinfected rats, whereas transaminase levels significantly ( p < 0.001) increased in the same coinfected group. Conclusion: This model provides many important features of Salmonella and Plasmodium sequential coinfection and therefore may be used as a tool to better understand, diagnose, and care for human malaria and/or typhoid pathogenesis.

Objective: To evaluate the anti-shigellosis activity of the hydroethanol extract of Diospyros gilletii (D. gilletii) stem bark in Shigella flexneri (S. flexneri)-induced diarrheal mice. Methods: The hydroethanolic extract was obtained by maceration of D. gilletii stem bark in 70% hydroethanol (waterethanol; 30:70, v/v) solution. Then, mice pretreated with cyclophosphamide for immunosuppression were administered orally with an inoculum containing S. flexneri, and subsequently treated with 100, 200, and 400 mg/kg of the hydroethanol extracts for 10 days. The bacterial colonies were enumerated and hematological and biochemical parameters were determined. Serum pro-inflammatory mediators including IL-1β, IL-18, and TNF-α, and nitric oxide levels were quantified by ELISA. Histological analyses of the kidney, liver, and colon were also conducted. Results: Treatment with 200 and 400 mg/kg of the hydroethanolic extracts markedly inhibited the growth of S. flexneri. Moreover, treatment with D. gilletii extract downregulated the levels of IL-1β, IL-18, and TNF-α, and restored hematological and biochemical parameters as well as histological architecture of the colon, liver, and kidneys. Additionally, the oral administration of 2000 mg/kg D. gilletii extract did not induce any sign of toxicity, with a median lethal dose greater than 2000 mg/kg. Conclusions: D. gilletii extract demonstrates the anti-shigellosis effects in S. flexneri-induced diarrheal mice, supporting the traditional use of this plant in treating diarrhea.

This paper explores the One Health approach as a vital framework for addressing food security and safety issues in Sub-Saharan Africa, particularly in the context of nutrition, health, and climate change. The interconnections between animal health, human health, and environmental sustainability highlight the need for integrated health policies that foster collaboration among the agriculture, health, and environmental sectors. Investment in interdisciplinary research is essential for identifying innovative and sustainable agri-food practices that can enhance regional food security. Emphasis should be placed on research initiatives that focus on sustainable agricultural methods, the development of climate-resilient crops, and effective pest management strategies, ensuring robust food systems that can adapt to the challenges of climate change. Moreover, promoting education and training is critical for empowering local farmers, healthcare professionals, and policymakers with the knowledge to implement One Health principles effectively. Educational initiatives can raise awareness of best practices in food production and handling, ultimately improving public health. Strengthening surveillance and monitoring systems is also crucial for early identifying and managing zoonotic diseases and foodborne pathogens, providing necessary data for informed decision-making. Finally, encouraging sustainable agricultural practices such as organic farming and agroecology is paramount for enhancing food safety and security. Policymakers must create incentives to support these transitions and engage communities in the decision-making processes to ensure that policies are contextually relevant. Overall, the findings emphasize the necessity of a holistic, collaborative approach to food security and safety in Sub-Saharan Africa, particularly in light of the region’s ongoing challenges related to nutrition, health, and climate change.

Background: Different parts of Allanblackia floribunda, Calotropis procera, Hymenocardia acida, Irvingia gabonensis, Newbouldia laevis, and Xylopia acutiflora have been used traditionally across different parts of Cameroon to overcome infectious diseases, especially pneumonia. Hence, this study investigated the antibacterial potential of six Cameroonian medicinal plants against selected ESKAPE pathogens (Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Escherichia coli, Pseudomonas aeruginosa) as well as Streptococcus pneumoniae. Methodology: The inhibitory activities of different extracts from six Cameroonian plants against the pathogens were evaluated by determining their MICs. Subsequently, the top four bioactive plant extracts were assessed for antibiofilm activity, time-kill kinetics, cytotoxicity (Raw and Vero cell lines), as well as antioxidant activities. Finally, the effect of the most potent extract, viz. ethanolic extract of Xylopia acutiflora steam bark, on bacterial morphology was elucidated through scanning electron microscopy while its phytochemical composition was profiled using liquid chromatography–mass spectrometry (LC–MS). Results: Twenty-two out of the 32 prepared extracts showed significant antibacterial activity, with MICs varying from 31.5 to 1000 µg/mL. The ethanolic, methanolic, and hydroethanolic extracts from Xylopia acutifolia and ethanolic extract from Colotropix procera exhibited broad-spectrum activity, inhibiting and eradicating bacterial biofilm. Furthermore, the extract from X. acutifolia was shown to be the most effective scavenger against DPPH (IC₅₀; 83.79 ± 1.92 µg/mL) and FRAP (IC₅₀; 22.89 ± 1.36 µg/mL) radicals, while C. procera extract was the most effective against ABTS (IC₅₀; 67.95 ± 1.83 µg/mL). The extracts were demonstrated to possess low cytotoxicity on both Raw and Vero cell lines. In addition, SEM revealed that X. acutifolia elicited cell membrane rupture and consequently cytoplasm leakage in E. coli and P. aeruginosa. Twenty-four different compounds were detected in the X. acutifolia extract via LC–MS analysis, and it was hypothesized that the recorded bioactivity in the extract might be ascribed to these compounds. Conclusion: Results from this study have scientifically validated the ethnomedicinal uses of the six Cameroonian plants as therapeutics for infections with X. acutiflora ethanolic extract displaying the highest bioactivity. Thus, there is the need for further investigations into phytochemicals from these plants as they could serve as important sources of novel antioxidants and antimicrobial agents. Graphical

Background: Malaria is a parasitic disease that affects many parts of the globe, especially sub-Saharan Africa. Over time, malaria parasites have become resistant to most antimalarial drugs, including artemisinin. Medicinal plants, which are used in the traditional treatment of malaria can afford effective drugs against this notorious disease. One such plant includes Vernonia blumeoides, which is used in the treatment of parasitic diseases, including malaria. Thus the scientific validation of the use of Vernonia blumeoides in ethnomedicine is of outstanding importance. Objectives: This study sought to investigate the antiplasmodial and antioxidant activity of extracts from Vernonia blumeoides; Methods: Vernonia blumeoides ethanol extract was obtained by maceration, and then subjected to phytochemical screening using standard protocols. The as-prepared extract was partitioned using solvents of increasing polarity to afford hexane, ethyl acetate, n-butanol fractions, and the water residue. The antiplasmodial potential of extract and fractions was determined by the Sybr green method. Antioxidant activity of V. blumeoides extracts was evaluated using DPPH, ABTS and FRAP assays. Cytotoxicity test was performed on murine macrophage Raw cells using the resazurin test; Results: The ethanol extract was obtained as a brown powder and the yield of extraction was found to be 43.95%. The phytochemical screening of this extract revealed the presence of tannins, alkaloids, flavonoids, phenolic compounds, and glycosides. Upon antiplasmodial screening against P. falciparum Dd2 and 3D7, the median inhibitory concentrations (IC50) of extract and fractions from V. blumeoides ranged from 4.70 to >100 µg/ml, with ethyl acetate extract having the lowest IC50 value and highest activity. Vernonia blumeoides extracts exhibited antioxidant activity with median scavenging concentrations ranging from 31.17 to 124.1 µg/mL, 50.84 to 500 µg/mL, and 33.95 to 500 µg/mL for ABTS, DPPH and FRAP assays, respectively. Cytotoxicity test of V. blumeoides extracts on Raw cells revealed non toxicity; Conclusions: This novel contribution demonstrated the antiplasmodial activity of V. blumeoides extracts, thus validating the ethnopharmacological use of this plant in the treatment of malaria symptoms. Nonetheless, in depth studies on the mechanisms of action, in vivo toxicity, as well as pharmacokinetic experiments are warranted for the successful utilization of this plant in ethnomedicine.

Plants from the Myrtaceae family are known to contain considerable quantities of volatile compounds, ranging from oxygenated monoterpenes to hydrogenated sesquiterpenes, and others, which exhibit antimicrobial activity. One such plant includes Syzygium aromaticum, which has been extensively used to treat a number of disorders, including bacterial and fungal infections. Thus, the scientific validation of the essential oil (EO) of Syzygium aromaticum vis-à-vis Candida and Cryptococcus species is valuable. To this end, the present study sought to investigate the antifungal activity of EO from S. aromaticum (clove) leaves and flower buds against Candida and Cryptococcus species. The antioxidant activity of S. aromaticum’s essential oils was also elucidated. The EO was extracted from fresh leaves and floral buds of S. aromaticum using a Clevenger-type apparatus. The as-prepared essential oils were further evaluated for antifungal activity against Candida and Cryptococcus species using a microdilution method. The phytochemical analysis of the EOs was assessed by gas chromatography/mass spectrometry (GC-MS). Antioxidant activities of the EOs were evaluated using standard methods. As a result, the GC-MS analysis revealed the presence of volatile compounds, such as eugenol (87.08%), β-caryophyllene (6.40%) and acetyleugenol (4.45%) as the major constituents of EO from the flower buds, and eugenol (90.54%) and β-caryophyllene (8.42%) as the major components of the leaf’s EO. The eugenol-rich essential oils exhibited significant antifungal effects against Candida species (common MIC value: 200 ppm) and Cryptococcus neoformans (MIC value: 50 ppm), as well as antioxidant activity. Overall, essential oils of S. aromaticum demonstrated antioxidant and antifungal effects, thus validating the ethnopharmacological use of this plant in the treatment of fungal infections. However, antifungal mechanisms of action, in-depth toxicity and in vivo experiments, and pharmacokinetics are warranted to support the use of this plant in ethnomedicine.

Plants from the Myrtaceae family are well known to contain considerable amounts of volatile compounds, ranging from oxygenated monoterpenes to hydrogenated sesquiterpenes, and others, which exhibit antimicrobial activity. One such plant includes Syzygium aromaticum that has been extensively used to treat a number of disorders, including bacterial and fungal infections. Thus, the scientific validation of the essential oil (EO) of Syzygium aromaticum vis-à-vis Candida and Cryptococcus species is valuable. To this end, the present study sought to investigate the antifungal activity of EO from S. aromaticum (clove) leaves and flower buds against Candida and Cryptococcus species. The antioxidant activity of S. aromaticum’s essential oils is also elucidated. The EO was extracted from fresh leaves and floral buds of S. aromaticum using a Clevenger-type apparatus. The as-prepared essential oils were further evaluated for antifungal activity against Candida and Cryptococcus species using a microdilution method. The phytochemical analysis of the EOs was assessed by gas chromatography/mass spectrometry (GC-MS). Antioxidant activities of the EOs were evaluated using standard methods. As a result, the GC-MS analysis revealed the presence of volatile compounds, such as eugenol (87.08%), β-caryophyllene (6.40%) and acetyleugenol (4.45%) as the major constituents of EO from the flower buds ; and eugenol (90.54%) and β-caryophyllene (24.65%) as the major components of the leaf’s EO. The eugenol-rich essential oils exhibited significant antifungal effects against Candida species (common MIC value: 200 ppm) and Cryptococcus neoformans (MIC value: 50 ppm), as well as antioxidant activity. Overall, essential oils of S. aromaticum demonstrated an-tioxidant and antifungal effects, thus validating the ethnopharmacological use of this plant in the treatment of fungal infections. However, antifungal mechanisms of action, in-depth toxicity and in vivo experiments, and pharmacokinetics are warranted to support the use of this plant in ethnomedicine.

Caused by pathogenic microorganisms, infectious diseases are known to cause high mortality rates, severe burdens of disability, and serious worldwide aftermaths. Drug-resistant pathogens have reduced the efficacy of available therapies against these diseases, thus accentuating the need to search for effective antimicrobials. Medicinal plants have served as starting material for the preparation of a number of antimicrobial agents. To this end, the present study highlights the green synthesis of Cocos nucifera-based nanomaterials and evaluation of the mechanistic basis of their antimicrobial action. Accordingly, Cocos nucifera extract was used for the reduction of silver nitrate solution to afford silver nanoparticles. These entities were further incorporated onto sulfuric-acid-based activated carbons to generate the nanocomposites. The antimicrobial activity of the as-prepared nanomaterials was evaluated using the broth microdilution method, while the antioxidant activity was assessed through standard methods. The cytotoxicity of potent nanomaterials was assessed on Vero cells by the spectrophotometric method. As a result, nanoparticles were successfully synthesized, as evidenced by the ultraviolet–visible spectroscopy analysis that revealed an intense absorption spectrum at 433 nm. Fourier Transform Infrared Spectroscopy presented the functional group moieties involved as a capping and reducing agent in the synthesis of the nanomaterials. The incubation of nanomaterials with selected bacterial and fungal strains has led to significant inhibitory effects of these pathogens with minimum inhibitory concentrations ranging from 7.813 to 250 μg/mL. In antioxidant assays, the nanocomposites presented scavenging activities comparable to those of ascorbic acid. Cytotoxicity experiment revealed no toxic effects on Vero cells (range of selectivity indices: from >4 to >128). These results provide evidence of the implication of Cocos nucifera-based nanomaterials in targeting bacterial or fungal systems that mediate free-radical damage or by inhibiting the oxidative damage caused by selected bacteria and fungi, the most susceptible being Escherichia coli and Candida albicans, respectively.

Shigellosis is a pathological condition that affects the digestive system and possibly causes diarrhoea. Shigella species, which are responsible for this disease, are highly contagious and spread through contaminated food and water. The increasing development of resistance by Shigella species necessitates the urgent need to search for new therapies against diarrhoea-causing shigellosis. The scientific validation of medicinal plants, such as Diospyros gilletii, which is used for the traditional treatment of diarrhoeal conditions is worthwhile. The present study aims to investigate the antibacterial activity of extracts from D. gilletii against selected Shigella species. Extracts from D. gilletii stem bark were prepared by maceration using various solvents. The antibacterial activity of D. gilletii extracts was evaluated in Shigella dysenteriae, S. flexneri, S. boydii, and S. sonnei using a microdilution method, whereas a cytotoxicity test was performed on Vero and Raw cells using resazurin-based colorimetric assays. Bacterial membrane-permeability studies were evaluated using propidium iodide (PI)- and 1-N-phenyl-naphthylamine (NPN)-uptake assays, whereas inhibition and eradication tests on bacterial biofilms were carried out by spectrophotometry. As a result, methanol, ethanol and hydroethanol (water: ethanol; 30:70, v/v) extracts of D. gilletii inhibited the growth of S. boydii, S. flexneri and S. sonnei, with minimum inhibitory concentration (MIC) values ranging from 125 to 500 µg/mL, without toxicity to Vero and Raw cells. Time-kill kinetics revealed bactericidal orientation at 2 MIC and 4 MIC and a bacteriostatic outcome at 1/2 MIC. The mechanistic basis of antibacterial action revealed that D. gilletii extracts inhibited and eradicated Shigella biofilms and promoted the accumulation of NPN and PI within the inner and outer membranes of bacteria to increase membrane permeability, thereby causing membrane damage. This novel contribution toward the antibacterial mechanisms of action of D. gilletii extracts against Shigella species substantiates the use of this plant in the traditional treatment of infectious diarrhoea.