Antimicrobial, antioxidant, and cytotoxic properties of biosynthesized copper oxide nanoparticles (CuO-NPs) using Athrixia phylicoides DC.

Nanoparticles produced from various metal elements including copper have been used in the treatment of infectious diseases in response to antibiotic failure due to microbial resistance. Copper is recommended for use in the production of nanoparticles largely because of its accessibility and affordability. This study aimed to synthesise copper oxide nanoparticles (CuO-NPs) using leaf extracts of Athrixia phylicoides and assess their antibacterial, antioxidant and cytotoxicity properties. The characterization of the obtained NPs was done through X-ray diffraction (XRD), Fourier transforms infrared spectroscopy (FTIR), Scanning electron microscopy (SEM) and Energy-dispersive spectroscopy (EDS). Our results showed that the NPs had a highly crystalline, quasi-spherical shape with an average diameter of 42 nm. Also, gram-positive bacteria Bacillus cereus and Staphylococcus aureus were the most susceptible to CuO-NPs with MIC values of 0.62 mg/mL and 0.16 mg/mL, respectively, as shown by the broth microdilution method. In addition, CuO-NPs demonstrated strong radical 2,2-diphenyl-1-picrylhydrazyl (DPPH) inhibitory activity with an IC50 value of 10.68 ± 0.03 µg/mL. However, the cytotoxicity activity determined by (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide) (MTT) assay revealed that the CuO-NPs were not toxic to human embryonic kidney cells (HEK 293 cells) at an LC50 value of 66.08 ± 0.55 µg/mL. The synthesised CuO-NPs showed high antibacterial, and antioxidant potency and less toxicity. Therefore, they could be a feasible alternative source of therapeutic agents in treating bacterial and oxidative stress-induced diseases.

Metabolomic profile of medicinal plants with anti-RVFV activity.

Twenty medicinal plants with previously established anti-viral activity against a wild-type RVFV were further investigated using bio-chemometric and analytical techniques. The aim being to identify compounds common in plants with anti-RVFV activity, potentially being the major contributors to the anti-viral effect. Proton nuclear magnetic resonance (1H NMR) spectroscopy coupled with multivariate data analysis (MVDA) was applied to characterize metabolite profiles of twenty antiviral medicinal plants. Discrimination and prediction of metabolome data of active anti-RVFV from the less-active samples was assessed using the multivariate statistical models by constructing a robust principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA) regression model. Annotation of metabolites in the samples with higher activity were performed by Chenomx software and the compounds confirmed using Ultra-High-Performance Liquid Chromatography-Quadrupole Time-of-Flight Mass Spectrometry (UHPLC-qTOF-MS). Both the PCA and OPLS-DA score plots showed clustering of samples; however, the OPLS-DA plot indicated a clear separation among active and less-active samples. Metabolic biomarkers were screened by p-value < 0.05 and variable importance in the projection (VIP) value >1 and S-plot. Among active samples, the most prominent metabolites putatively identified by NMR include trigonelline, vanillic acid, fumarate, chlorogenic acid, ferulate, and formate. The presence of the compounds were confirmed by UHPLC-qTOF-MS, and two hydroxylated fatty acids were additionally detected indicated by peaks at m/z 293.2116 and m/z 295.2274 13S-Hydroxy-9Z,11E,15Z-octadecatrienoic acid and 13-Hydroxy-9Z,11E-octadecadienoic acid were annotated for the first time in all the antiviral active samples and are considered potential metabolites responsible for the antiviral activity. The study provides a metabolomic profile of anti-RVFV plant extracts and report for the first time the presence of hydroxylated fatty acids 13S-Hydroxy-9Z,11E,15Z-octadecatrienoic acid and 13-Hydroxy-9Z,11E-octadecadienoic acid, present in all the tested medicinal plants with high anti-RVFV activity and is a potential target for the future development of antiviral therapeutic agents.

The attenuation of antibiotic resistant non-albicans Candida species, cytotoxicity, anti-inflammatory effects and phytochemical profiles of five Vachellia species by FTIR and UHPLC-Q/Orbitrap/MS.

This work investigated the antifungal, cytotoxic and LPS-induced anti-inflammatory effects of five Vachellia species (V. karroo, V. kosiensis, V. sieberiana, V. tortalis and V. xanthophloea). The antifungal activity of the aqueous-methanolic extracts were performed using the broth dilution method against four non-albicans Candida species (C. glabrata, C. auris, C. tropicalis and C. parapsilosis). The cytotoxic and anti-inflammatory effects of the extracts were evaluated on African green monkey Vero kidney cells using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) colorimetric assay and the 2',7'-dichlorofluorescin diacetate (H2DCF-DA) method. The fourier-transform infrared spectroscopy (FTIR) and Q Exactive plus orbitrap™ Ultra-high-performance liquid chromatography-mass spectrometer (UHPLC-MS) analysis was conducted to evaluate phytochemical constituents of the extracts. The plant extracts selected in this study displayed potency against the Candida species tested, with MIC values ≤0.62 mg/mL for V. karroo, V. kosiensis and V. xanthophloea. A dose-dependent cell viability was observed on Vero cells with all extracts showing LC50 values >20 µg/mL. Extracts tested at 10 µg/mL elicited a significant decrease in lipopolysaccharide (LPS)-induced reactive oxygen species (ROS) in Vero cells with V. sieberiana, V. tortilis, V. karroo, V. kosiensis and V. xanthophloea displaying inhibitory percentages of 35%, 32%, 55%, 52% and 49%, respectively. Characterisation of functional groups representing compounds in the extracts demonstrated the presence of different classes of compounds of the aliphatic, sugar and aromatic types. The Q Exactive plus orbitrap™ mass spectrometer enabled tentative identification of three major compounds in the extracts, including epigallocatechin, methyl gallate and quercetin amongst others. Based on the mass spectrometer results, it is postulated that quercetin found mostly in active extracts of V. karroo, V. xanthophloea, and V. kosiensis may be responsible for the observed antifungal and anti-inflammatory activity. This data demonstrates that the Vachellia species that were investigated could potentially be promising candidates for the management of fungal infections and related inflammation.

Metabolomic Profiling of Antioxidant Compounds in Five Vachellia Species.

The genus Vachellia, previously known as Acacia, belongs to the family Fabaceae, subfamily Leguminosae, which are flowering plants, commonly known as thorn trees. They are traditionally used medicinally in various countries including South Africa for the treatment of ailments such as fever, sore throat, Tuberculosis, convulsions and as sedatives. The aim of this study was to determine biochemical variations in five Vachellia species and correlate their metabolite profiles to antioxidant activity using a chemometric approach. The antioxidant activity of five Vachellia aqueous-methanolic extracts were analyzed using three methods: 2,2-di-phenyl-1-picrylhydrazyl (DPPH) radical scavenging assay, 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid (ABTS+) analysis and the ferric reducing antioxidant power (FRAP) assay by means of serial dilution and bioautography with the thin-layer chromatography (TLC) method. Amongst the Vachellia extracts tested, V. karroo, V. kosiensis and V. xanthophloea demonstrated the highest DPPH, ABTS+ and FRAP inhibitory activity. The antioxidant activities of DPPH were higher than those obtained by ABTS+, although these values varied among the Vachellia species. Proton nuclear magnetic resonance (1H NMR), coupled with multivariate statistical modeling tools such as principal component analysis (PCA) and orthogonal partial least squares discriminant analysis (OPLS-DA), were performed to profile metabolites responsible for the observed activity. The OPLS-DA categorized the five Vachellia species, separating them into two groups, with V. karroo, V. kosiensis and V. xanthophloea demonstrating significantly higher radical scavenging activity than V. tortilis and V. sieberiana, which clustered together to form another group with lower radical scavenging activity. Annotation of metabolites was carried out using the ultra-high-performance liquid chromatography-quadrupole time-of-flight mass spectrometry (UHPLC-qTOF-MS), and it tentatively identified 23 metabolites of significance, including epigallocatechin (m/z = 305.0659), methyl gallate (m/z = 183.0294) and quercetin (m/z = 301.0358), amongst others. These results elucidated the metabolites that separated the Vachellia species from each other and demonstrated their possible free radical scavenging activities.

Lithium inhibits NF-κB nuclear translocation and modulate inflammation profiles in Rift valley fever virus-infected Raw 264.7 macrophages.

INTRODUCTION: Rift Valley fever virus (RVFV) is a zoonotic life-threatening viral infection endemic across sub-Saharan African countries and the Arabian Peninsula; however, there is a growing panic of its spread to non-endemic regions. This viral infection triggers a wide spectrum of symptoms that span from fibril illnesses to more severe symptoms such as haemorrhagic fever and encephalitis. These severe symptoms have been associated with dysregulated immune response propagated by the virulence factor, non-structural protein (NSs). Thus, this study investigates the effects of lithium on NF-κB translocation and RFVF-induced inflammation in Raw 264.7 macrophages. METHODS: The supernatant from RVFV-infected Raw 264.7 cells, treated with lithium, was examined using an ELISA assay kit to measure levels of cytokines and chemokines. The H2DCF-DA and DAF-2 DA florigenic assays were used to determine the levels of ROS and RNS by measuring the cellular fluorescence intensity post RVFV-infection and lithium treatment. Western blot and immunocytochemistry assays were used to measure expression levels of the inflammatory proteins and cellular location of the NF-κB, respectively. RESULTS: Lithium was shown to stimulate interferon-gamma (IFN-γ) production as early as 3 h pi. Production of the secondary pro-inflammatory cytokine and chemokine, interleukin-6 (IL-6) and regulated on activation, normal T cell expressed and secreted (RANTES), were elevated as early as 12 h pi. Treatment with lithium stimulated increase of production of tumor necrosis factor-alpha (TNF-α) and Interleukin-10 (IL-10) in RVFV-infected and uninfected macrophages as early as 3 h pi. The RVFV-infected cells treated with lithium displayed lower ROS and RNS production as opposed to lithium-free RVFV-infected control cells. Western blot analyses demonstrated that lithium inhibited iNOS expression while stimulating expression of heme oxygenase (HO) and IκB in RVFV-infected Raw 264.7 macrophages. Results from immunocytochemistry and Western blot assays revealed that lithium inhibits NF-κB nuclear translocation in RVFV-infected cells compared to lithium-free RVFV-infected cells and 5 mg/mL LPS controls. CONCLUSION: This study demonstrates that lithium inhibits NF-kB nuclear translocation and modulate inflammation profiles in RVFV-infected Raw 264.7 macrophage cells.