Aloe arborescens Mill’s extracts have been explored for antibacterial and antioxidant efficacies. However, there is limited information on its chemical composition and mechanism of action. The purpose of this study was to assess the chemical composition, antibacterial and antioxidant activities and mechanism of the whole leaf extract of A. arborescens Mill. The phytochemical profile was analysed with gas chromatography mass spectrometry (GC-MS). The antioxidant and antibacterial activities were screened using 1,1diphenyl2picrylhydrazyl (DPPH), 2,2′-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and micro-dilution assays, respectively. The effects of the extract on the bacterial respiratory chain dehydrogenase, membrane integrity and permeability were analysed using iodonitrotetrazolium chloride, 260 absorbing materials and relative electrical conductivity assays. GC-MS spectrum revealed 26 compounds with N,N’-trimethyleneurea (10.56%), xanthine (8.57%) and 4-hexyl-1-(7-ethoxycarbonylheptyl)bicyclo[4.4.0]deca-2,5,7-triene (7.10%), being the major components. The extract also exhibited antioxidant activity with median concentration (IC₅₀) values of 0.65 mg/mL on DPPH and 0.052 mg/mL on ABTS. The extract exhibited minimum inhibitory concentration (MIC) values ranging from 0.07 to 1.13 mg/mL. The extract inhibited the bacterial growth by destructing the activity of the respiratory chain dehydrogenase, membrane integrity and permeability. Therefore, the leaf extract has the potential to serve as a source of antibacterial and antioxidant compounds.

The constant increase in drug resistance, occurrence of incurable diseases and high medical costs, have necessitated bio-prospecting of fungi as alternative sources of therapeutic compounds. This study aimed at assessing the antibacterial effect and mode of action of secondary metabolites from fungal endophyte associated with Aloe ferox Mill. Endophytic fungus was isolated from the gel of A. ferox and identified by internal transcribed spacer (ITS) rRNA gene sequence analysis. The targets of antibacterial activity were assessed based on minimum inhibitory concentration (MIC) and the effect of the extract on respiratory chain dehydrogenase (RCD) and membrane integrity. Fourier transform-infrared spectrophotometer (FTIR) was employed to ascertain functional groups. The fungus with the most promising antibiotic-production was identified as Aspergillus welwitschiae MK450668.1. Its extract exhibited antibacterial activity with the MIC values of 0.5 and 1 mg/mL against Staphylococcus aureus (ATCC 25925) and Escherichia coli (ATCC 25922). It demonstrated the inhibitory effect on the RCD activity and destruction of membrane integrity on the test bacteria. FTIR spectrum revealed hydroxyl, amine and alkene groups. A. welwitschiae MK450668.1 serves as a potential source of effective compounds to combat the challenge of drug resistance.

While the Zygomycete fungus Conidiobolus coronatus primarily infects insects, it can be pathogenic to mammals as well, including humans. High variability in the treatment of this fungal infection with currently available drugs, including azole drugs is a very common phenomenon. Azoles bind to the cytochrome P450 monooxygenases (P450s/CYP) including CYP51, a sterol 14-α-demethylase, inhibiting the synthesis of cell membrane ergosterol and thus leading to the elimination of infecting fungi. Despite P450’s role as a drug target, to date, no information on C. coronatus P450s has been reported. Genome-wide data mining has revealed the presence of 142 P450s grouped into 12 families and 21 subfamilies in C. coronatus. Except for CYP51, the remaining 11 P450 families are new (CYP5854-CYP5864). Despite having a large number of P450s among entomopathogenic fungi, C. coronatus has the lowest number of P450 families, which suggests blooming P450s. Further analysis has revealed that 79% of the same family P450s is tandemly positioned, suggesting that P450 tandem duplication led to the blooming of P450s. The results of this study; i.e., unravelling the C. coronatus P450 content, will certainly help in designing experiments to understand P450s’ role in C. coronatus physiology, including a highly variable response to azole drugs with respect to P450s.

Green synthesis of core–shell nanoparticles is gaining importance nowadays as it is viewed as being environmental friendly and cost effective. The present study aimed to synthesize iron@copper core–shell nanoparticles using a polysaccharide-based bioflocculant from Alcalegenis faecalis and to evaluate its efficiency in dye removal and river water and domestic wastewater treatment. The synthesized samples were characterized by Fourier-transform infrared spectroscopy, X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, transmission electron microscopy, and UV-Vis spectroscopy analysis. To optimize the best concentration for core–shell formation, different ratios of iron to copper were prepared. Sample 1 (S1) contained 1:3 iron to copper (Fe 25%–Cu 75%), sample 2 (S2) contained 1:1 iron to copper (Fe 50%–Cu 50%), and the third sample (S3) contained 3:1 iron to copper (Fe 75%–Cu 25%). The flocculation activity (FA) was above 98% at 0.2 mg/mL for all the samples and the samples flocculated well under acidic, alkaline, and neutral pH conditions. Sample 3 was shown to be thermostable, with flocculation activity above 90%, and samples 2 and 1 were also thermostable, but the flocculation decreased to 87 at 100 °C. All three samples revealed some remarkable properties for staining dye removal as the removal efficiency was above 89% for all dyes tested. The synthesized core–shell nanoparticles could remove nutrients such as total nitrogen and phosphate in both domestic wastewater and Mzingazi river water. Furthermore, high removal efficiency for chemical oxygen demand (COD) and biological oxygen demand (BOD) was also observed.