The Indiscriminate Chemical Makeup of Secondary Metabolites Derived from Endophytes Harvested from Aloe barbadensis Miller in South Africa's Limpopo Region.

The efficacy of 23 bacterial isolates obtained from surface-sterilized stems and leaves of three medicinal plants (Aloe barbadensis Miller, Artemisia afra, and Moringa oleifera) was investigated in an endeavour to prevent the growth of Mycobacterium bovis using the cross-streak method. Endophytes were isolated by incubating sterile plant materials on nutrient agar at 30 °C for 5 days. Two isolates showing activity were subsequently utilized to produce the extracts. Whole-genome sequencing (WGC) was used to identify the isolates. Secondary metabolites produced after 7 days of growth in nutrient broth were harvested through extraction with ethyl acetate. The extracts were chemically profiled using gas chromatography-high resolution time-of-flight mass spectrometry (GC-HRTOF-MS). NCBI BLAST search results revealed that the isolated endophytes belonged to the Pseudomonas and Enterobacter genera, based on WGC. Two endophytes, Aloe I4 and Aloe I3-I5 from Aloe barbadensis, exhibited potency based on the cross-streak method. The metabolite profiling of the selected endophytes identified 34 metabolites from Aloe I4, including ergotamine, octadecane, L-proline and 143 other metabolites including quinoline and valeramide, which inhibit microbial quorum sensing. These findings suggest that bacterial endophytes from medicinal plants, particularly Aloe barbadensis, hold promise as sources of antimycobacterial agents for human health applications.

Dissolvable wound dressing loaded with silver nanoparticles together with ampicillin and ciprofloxacin.

Aim: The current study is focused on the development of water-soluble wound dressings, which are potential dressings for the treatment of burn wounds. Materials & methods: Sodium alginate-based dissolvable wound dressings were prepared and loaded with silver nanoparticles and various antibiotics (ampicillin and ciprofloxacin) followed by characterization and in vitro antibacterial studies. Results & conclusions: The prepared sodium alginate-based dissolvable wound dressing exhibited good porosity, water uptake and moisture content, promising antibacterial activity, high absorption capacity of simulated wound exudates, excellent water vapor transmission rate in the range of 2000 to 5000 g/m2 day-1, sustained drug-release profiles and water solubility. The wound dressings were active against Proteus mirabilis, Staphylococcus aureus, Proteus vulgaris, Escherichia coli and Klebsiella aeruginosa strains of bacteria. The results obtained revealed the wound dressing as potential wound dressings for burn wounds and sensitive skin.

Comparative Assessment of Antifungal and Antibacterial Activities of Crude Extracts of the King Tuber Culinary-Medicinal Mushroom, Pleurotus tuber-regium (Agaricomycetes) from Cameroon.

Antifungal and antibacterial activities of crude extracts of carpophore compared with those of sclerotium of Pleurotus tuber-regium were investigated on 11 species of bacterial and 3 fungal human pathogens. The minimal inhibitory concentration (MIC) of carpophore extract was recorded to be 12.5 mg/mL on Bacillus subtilis, Enterococcus faecalis, Staphylococcus epidermidis, Escherichia cloacae, Proteus mirabilis, P. vulgaris, Klebsiella oxytoca, and K. aerogenes and 6.25 mg/mL on Staphylococcus aureus, Escherichia coli, and Mycobacterium smegmatis as well as on all three species of fungal pathogens including Candida albicans, Aspergillus fumigatus, and A. ochraceus. In comparison, the MIC of sclerotium was recorded to be 12.5 mg/mL on Bacillus subtilis and Klebsiella aerogenes; 6.25 mg/mL on Enterococcus faecalis, Staphylococcus aureus, S. epidermidis, Enterobacter cloacae, E. coli, Mycobacterium smegmatis, Proteus mirabilis, P. vulgaris, and Klebsiella oxytoca; and 3.13 mg/mL on the three fungal pathogens. Based on the abovementioned figures, it appears that strains of pathogenic fungi tested are much more sensitive to crude extracts than the abovementioned bacteria. In fact, antimicrobial activities of crude extracts of P. tuber-regium, no matter whether it is that of the carpophore or its sclerotium, are in general stronger on human pathogenic fungi than bacteria. These figures also demonstrate that crude extracts of sclerotium show a higher antimicrobial activity than that of carpophore. Carpophores and sclerotia of P. tuber-regium could therefore constitute a source of new molecules potentially more efficient than synthetic products against some human pathogenic fungi and bacteria.

Benzimidazole Schiff base derivatives: synthesis, characterization and antimicrobial activity.

A series of Schiff bases (3.a-f) bearing benzimidazole moiety was successfully synthesized in ethanol by refluxing Oct-2-ynoic acid (1,3-dihydrobenzimidazole-2-ylidene)amide with substituted amines. Fourier transform infrared (FTIR), ultra violet light (UV-VIS), elemental analysis, proton (1H) and carbon (13C) nuclear magnetic resonance spectroscopy were used to characterize the newly synthesized Schiff bases. Micro dilution method was used to determine the minimum inhibitory concentration (MIC) and minimum fungicidal concentration (MFC) of the Schiff bases, against 14 human pathogenic bacteria (8 Gram negative and 6 Gram positive) and against 7 fungal strains (5 Aspergillus and 2 Fusarium) representatives. Antimalarial activity against Plasmodium falciparum and antitrypanosomal property against Trypanosoma brucei was studied in vitro at a single dose concentration of the Schiff bases. Cytotoxicity of the Schiff bases was assessed against human cervix adenocarcinoma (HeLa) cells. Results obtained show that the newly synthesized Schiff bases are very potent antimicrobial agents. Gram negative bacteria Klebsiella pneumonia and Escherichia coli were more affected on exposure to Compounds 3.c-f (MIC 7.8 µg/mL) which in turn exhibited more antibacterial potency than nalidixic acid reference drug that displayed MICs between 64 and 512 µg/mL against K. pneumonia and E. coli respectively. The test compounds also demonstrated high cytotoxic effect against Aspergillus flavus and Aspergillus carbonarius as they displayed MFC 7.8 and 15.6 µg/mL. Compound 3.c exhibited the highest fungicidal property from this series with MFC alternating between 7.8 and 15.6 µg/mL against the investigated strains. The malarial activity revealed Compounds 3.c and 3.d as the more potent antiplasmodial compounds in this group exhibiting 95% and 85% growth inhibition respectively. The IC50 of Compounds 3.c and 3.d were determined and found to be IC50 26.96 and 28.31 µg/mL respectively. Compound 3.a was the most cytotoxic agent against HeLa cells in this group with 48% cell growth inhibition. Compounds 3.c, 3.d and 3.f were biocompatible with HeLa cells and displayed low toxicity. With a very low cytotoxic effect against HeLa, compound 3.c stands out to be a very good antiparasitic agent and consideration to further evaluate the candidate drug against others cell lines is necessary.