Branly-Natalien Nguena-Dongue

Despite the potential of mycelium-based biomaterials as renewable alternatives to synthetic materials in the biomedical, construction, fashion, and packaging industries, their translation into scalable applications is hindered by reliance on a limited number of species, resource-intensive cultivation, and poorly understood substrate–property dynamics. Thus, we systematically screened various fungal isolates, resulting in the identification of seven non-pathogenic species with strong potential as biomaterials, viz., Absidia koreana , Achaetomium globosum , Cubamyces lactineus , Hypoxylon sp., Mucor fragilis , Periconia macrospinosa , and Xylaria berteroi . Subsequently, the fungi were cultivated on agro-residues and various commercial media to assess the effects of growth substrates on mycelial development and material properties. Quantitative analyses revealed that wheat bran agar (WBA) media competed favourably with Sabouraud dextrose agar (SDA), promoting denser, more cohesive mycelial networks despite their lower refinement and lower cost. Fourier transform infrared spectroscopy revealed distinct modulation of polysaccharide-, protein-, and chitin-associated functional groups, suggesting substrate-driven biochemical remodelling across different mycelia, while scanning electron microscopy showed enhanced hyphal interconnectivity, surface roughness, and microstructural heterogeneity in mycelia produced on agro-residues. Notably, A. koreana was identified as the most promising of all the evaluated fungi based on biomass productivity and thermal resistance (295 °C), as well as its smooth, branched, and thick hyphae network with the highest average diameter (5.02 ± 0.38 µm on SDA and 6.99 ± 0.53 µm on WBA). The dynamic mechanical analysis highlighted the effect of the growing substrates on the mechanical performance of the derived mycelium sheet, with the highest ultimate stress of 15.54 MPa, maximum storage modulus of 2109 MPa, and the maximum loss modulus of 107.9 MPa for X. berteroi on SDA, the highest storage modulus at lower temperature of 1332 MPa for P. macrospinosa on SDA, while the highest damping behaviour at lower temperature (45 °C) of 0.115 for Hypoxylon sp., and the maximum damping behaviour of 0.451 for X. berteroi on WBA. Finally, elemental analysis of agro-residues indicates their reusability for sustainable fungal cultivation in biotechnological industries. Collectively, these findings demonstrate that agro-residues are not merely viable substitutes for commercial media but represent superior platforms for tailoring mycelium material properties. Key points: • Improvement of fungal growth structure and protein content on agro-waste relative to commercial media. • Thermal stability of Absidia koreana mycelium, a top biomaterial candidate. • Compositional analysis indicates the reusability of agro-wastes as growth substrates.

Background: Liver diseases are increasingly recognized as significant public health issues, with cirrhosis alone ranking 12th as the leading cause of death worldwide. This study aimed to evaluate the anti-fibrotic effects of ethanolic leaf extract of Crinum distichum (CDE) in male Wistar rats with Carbon tetrachloride (CCl4)-induced liver fibrosis. Methods: Phytochemical profiling of CDE was assessed through High Performance Liquid Chromatography/Mass spectrometry (HPLC/MS) analysis. Seventy male Wistar rats were randomly divided into six groups: control group, CCl4-intoxicated group, and CCl4-intoxicated group + sylimarin (100 mg/kg body weight (b.w)) group, 3 other CCl4-intoxicated groups receiving different doses of CDE at 100, 200, and 400 mg/kg b.w, respectively. Liver fibrosis was induced by intraperitoneal administration of 50% CCl4 (2 mL/kg b.w) dissolved in olive oil twice a week for 6 weeks. Afterward, animals were orally treated once per day with CDE or silymarin for 7 or 14 consecutive days. Animals were sacrificed, and biochemical parameters related to liver damage and liver histology were assessed at each time point. Student's t-test or One-way ANOVA followed by Bonferroni’s post hoc test using Graphpad Prism software was used to analyze the data obtained. P < 0.05 was considered significant. Results: Verbaboside, citroside A, Apigenin 7-O-(6''-O-acetylglucoside), and 9,12,13-TriHOME were the phytochemicals successfully identified in CDE. The treatment of CCl4-intoxicated rats with CDE significantly (p<0.05) decreased serum activity of alanine and aspartate aminotransferase, as well as hepatic content of triglycerides and total cholesterol, as compared to CCl4-intoxicated and non-treated animals. Similarly, in CCl4-intoxicated rats, CDE treatment significantly (p<0.05) decreased hepatic content of malondialdehyde, restored the activity of antioxidant superoxide dismutase and catalase, and preserved the normal liver architecture. Conclusion: Our findings highlighted the ability of CDE to reverse CCl4-induced liver fibrosis in rats, and subsequently valorized C. distichum as a potential source of active ingredients for the treatment of liver fibrosis, though further in-depth investigations are necessary to confirm their anti-fibrotic effects.

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

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.

Caused by pathogenic microorganisms, such as bacteria, parasites, fungi, among others, infectious diseases can spread directly or from one individual to another. According to the World Health Organization, these diseases are known to cause high mortality rates, severe burdens of disability and serious worldwide aftermaths. The inappropriate use of antibiotics in humans are the main origins of the development of drug-resistant pathogens, which reduce the efficacy of these therapies, 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 to reduce different concentrations (5, 10 and 20 mM) of silver nitrate solution to afford silver nanoparticles (AgNPs). These entities were further incorporated onto activated carbons (obtained by chemical activation using sulphuric acid as activation agent) 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, such as 2,2-diphenyl-1-picrylhydrazyl (DPPH), and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS) assays. Cytotoxicity of potent nanomaterials was assessed on Vero cells by spectrophotometric method. As a result, nanoparticles were successfully synthesized as evidenced by the color change of the solution from transparent to dark brown. Further characterization was carried out by UV-visible spectroscopy that showed an intense absorption spectrum at 433 nm. Fourier Transform Infrared Spectroscopy (FTIR) revealed the functional group moieties involved as a capping and reducing agent in the synthesis of AgNPs. The incubation of nanomaterials with selected bacterial and fungal strains 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 that of ascorbic acid. Cytotoxicity experiment revealed no toxic effects on the human mammalian cells Vero (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 to possibly cause 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 necessitate the urgent need to search for new therapies against shigellosis causing diarrhoea. 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. An-tibacterial activity of D. gilletii extracts was evaluated on Shigella dysenteriae, S. flexneri, S. boydii, and S. sonnei using a microdilution method, whereas cytotoxicity test was performed on Vero and Raw cells using resazurin-based colorimetric assay. Bacterial membrane permeability studies were evaluated using pro-pidium iodide (PI) and 1-N-phenylnaphthylamine (NPN) uptake assays, whereas inhibition and eradica-tion tests on bacterial biofilms were carried out by spectrophotometry. As a result, methanol, ethanol and hydroethanol extracts of D. gilletii inhibited the growth of S. boydii, S. flexneri and S. sonnei with MIC values ranging from 125 to 500 µg/mL, without toxicity to Vero and Raw cells. Time kill kinetics revealed bacteri-cidal orientation at 2MIC and 4MIC, and bacteriostatic outcome at 1/2MIC. The mechanistic basis of anti-bacterial action revealed that D. gilletii extracts inhibited and eradicated Shigella biofilms, and promoted the accumulation of NPN and PI within the inner and outer membrane of bacteria to increase membrane per-meability, thereby causing membrane damage. This novel contribution toward the antibacterial and mech-anisms of action of D. gilletii extracts against Shigella species substantiate the use of this plant in the tradi-tional treatment of infectious diarrhoea.

Plants belonging to the genus Irvingia are widespread across the African and Southeast Asian regions of the world. Irvingia gabonensis, Irvingia malayana, and Irvingia grandifolia are among the commonly used species in ethnomedicine, especially in Africa. Fever, scabies, toothache, inflammation, and liver and gastrointestinal disorders are among the pathological conditions that are reverted by Irvingia plants upon traditional preparations. Modern pharmacological investigations have substantiated the ethnomedicinal uses of Irvingia spp. Reports on the phytochemical analysis of Irvingia plants have revealed the presence of a number of secondary metabolites such as flavonoids, phenolic compounds, tannins, saponins, and alkaloids. Based on the foregoing, the present study provides a comprehensive evaluation of reports on the ethnomedicinal use, phytochemistry, pharmacology, and toxicity of plants from the genus Irvingia. Relevant information on Irvingia plants was mostly obtained from major scientific databases from their inception until July 2023. As a result, more than forty compounds have been identified in Irvingia spp., proving the abundance of secondary metabolites in these plants. Reports have pointed out modern pharmacological activities such as antiprotozoal, antimicrobial, antioxidant, antidiabetic, anti-inflammatory, and hepatoprotective activities. The present study provides more insights for the successful utilization of Irvingia plants and may guide further research on their therapeutic potential in the treatment of various diseases.