Christo John Frederick Muller

Background: Hepatic lipid metabolism disorder has been linked to a wide range of diseases. Aspalathin is a flavonoid enriched in rooibos tea and has shown capacity to protect against hyperlipidemia, oxidative stress and inflammation. In the current study, we investigated the functional role of aspalathin in regulating liver metabolism and gut microbiota in the context of a high-fat diet (HFD). Methods: Male mice were fed a control diet or HFD, then HFD-fed animals were treated with or without aspalathin-rich extract (ASE). Hepatic neutral lipids were detected using oil red O staining and a colorimetric assay. Expression of cholesterol metabolism-, lipogenesis- and fatty acid β-oxidation-associated genes was measured. Gut microbiota was analyzed using 16S rRNA sequencing and bioinformatic approaches. Results: HFD-fed mice had markedly higher levels of triglycerides and cholesteryl esters and downregulated expression of cholesterol metabolism-, transport- and lipogenesis-related genes in the liver. ASE administration counteracted HFD-induced effects. In addition, HFD altered the composition, diversity and metabolic pathways of the gut microbiota. The richness of beneficial bacteria, particularly the butyrate-producing bacteria, was significantly decreased. The altered metabolic pathways are involved in the metabolism of carbohydrates, lipids, amino acids and nucleotides, as well as mitochondrial function. ASE treatment reversed most of the alterations back to the characteristics of the control group. Conclusions: Our results demonstrated the potential of ASE improving liver lipid metabolism and gut microbiota in the scenario of a high-fat diet, providing insights into future studies on the mechanism of ASE regulating lipid metabolism disorder.

Non-communicable diseases (NCDs) are the leading cause of death worldwide, with cardiovascular disease (CVD) accounting for half of all NCD-related deaths. The biological onset of CVD may occur long before the development of clinical symptoms, hence the urgent need to understand the molecular alterations underpinning CVD, which would facilitate intervention strategies to prevent or delay the onset of the disease. There is evidence to suggest that CVD develops through a complex interplay between genetic, lifestyle, and environmental factors. Epigenetic modifications, including DNA methylation, serve as proxies linking genetics and the environment to phenotypes and diseases. In the past decade, a growing list of studies has implicated DNA methylation in the early events of CVD pathogenesis. In this regard, screening for these epigenetic marks in asymptomatic individuals may assist in the early detection of CVD and serve to predict the response to therapeutic interventions. This review discusses the current literature on the relationship between blood-based DNA methylation alterations and CVD in humans. We highlight a set of differentially methylated genes that show promise as candidates for diagnostic and prognostic CVD biomarkers, which should be prioritized and replicated in future studies across additional populations. Finally, we discuss key limitations in DNA methylation studies, including genetic diversity, interpatient variability, cellular heterogeneity, study confounders, different methodological approaches used to isolate and measure DNA methylation, sample sizes, and cross-sectional study design.

The spread of SARS-CoV-2 has led to an interest in using ivermectin (a potent antiparasitic agent) as an antiviral agent despite the lack of convincing in vivo clinical data for its use against COVID-19. The off-target prophylactic use of ivermectin adds a substantial risk of drug–drug interactions with pharmaceutical medications used to treat chronic conditions like diabetes and hypertension (metformin and hydrochlorothiazide, respectively). Therefore, this study aims to evaluate the potential drug–drug interactions between ivermectin with either metformin or hydrochlorothiazide. In silico experiments and high-throughput screening assays for CYP3A4 were conducted to understand how metformin and hydrochlorothiazide might affect CYP3A4’s role in metabolizing ivermectin. The study findings indicated that hydrochlorothiazide is more stable than both ivermectin and metformin. This conclusion was further supported by root mean square fluctuation analysis, which showed that hydrochlorothiazide is more flexible. The variation in the principal component analysis scatter plot across the first three normal modes suggests hydrochlorothiazide has a more mobile conformation than ivermectin and metformin. Additionally, a strong inhibition of CYP3A4 by hydrochlorothiazide was observed, suggesting that hydrochlorothiazide’s regulatory effects could significantly impede CYP3A4 activity, potentially leading to a reduced metabolism and clearance of ivermectin in the body. Concurrent administration of these drugs may result in drug–drug interactions and hinder the hepatic metabolism of ivermectin.

Wastewater-based epidemiology (WBE) has been an important tool for the detection of COVID-19 outbreaks. The retrospective analysis of COVID-19 data is vital to understand the spread and impact of the virus as well as to inform future planning and response efforts. In this study, we evaluated the SARS-CoV-2 RNA levels in wastewater from 21 wastewater treatment plants (WWTPs) in the City of Cape Town (South Africa) over a period of 12 months and compared the (inactive) SARS-CoV-2 viral RNA in wastewater between wave 2 (November 2020 to January 2021) and wave 3 (June 2021 to September 2021). The SARS-CoV-2 RNA expression was quantified in wastewater using quantitative real-time PCR (qRT-PCR) by targeting the nucleocapsid (N) gene, and the resultant signal was normalized to the WWTP design capacity and catchment size. Our findings show that the maximum SARS-CoV-2 RNA signal was significantly higher in wave 3 than in wave 2 (p < 0.01). The duration of wave 3 (15 weeks) was longer than that of wave 2 (10 weeks), and the wastewater surveillance data supported the clinical findings, as evidenced by the two distinct waves. Furthermore, the data demonstrated the importance of long-term wastewater surveillance as a key indicator of changing trends.

Background: Currently, it is acknowledged that vitamin E, insulin sensitizers and anti-diabetic drugs are used to manage non-alcoholic fatty liver disease (NAFLD), however, these therapeutic interventions harbour adverse side effects. Pioglitazone, an anti-diabetic drug, is currently the most effective therapy to manage NAFLD. The use of natural medicines is widely embraced due to the lack of evidence of their negative side effects. Rooibos has been previously shown to decrease inflammation and oxidative stress in experimental models of diabetes, however, this is yet to be explored in a setting of NAFLD. This study was aimed at investigating the effects of an aspalathin-rich green rooibos extract (Afriplex GRT^TM) against markers of hepatic oxidative stress, inflammation and apoptosis in anin vitromodel of NAFLD.Methods: Oleic acid [1 mM] was used to induce hepatic steatosis in C3A liver cells. Thereafter, the therapeutic effect of Afriplex GRT^TM, with or without pioglitazone, was determined by assessing its impact on cell viability, changes in mitochondrial membrane potential, intracellular lipid accumulation and the expression of genes and proteins (ChREBP,SREBF1,FASN,IRS1,SOD2, Caspase-3, GSTZ1, IRS1 and TNF-α) that are associated with the development of NAFLD.Results: Key findings showed that Afriplex GRT^TMadded to the medium alone or combined with pioglitazone, could effectively block hepatic lipid accumulation without inducing cytotoxicity in C3A liver cells exposed oleic acid. This positive outcome was consistent with effective regulation of genes involved in insulin signaling, as well as carbohydrate and lipid metabolism (IRS1,SREBF1andChREBP). Interestingly, in addition to reducing protein levels of an inflammatory marker (TNF-α), the Afriplex GRT^TMcould ameliorate oleic acid-induced hepatic steatotic damage by decreasing the protein expression of oxidative stress and apoptosis related markers such as GSTZ1 and caspase-3.Conclusion: Afriplex GRT^TMreduced hepatic steatosis in oleic acid induced C3A liver cells by modulatingSREBF1,ChREBPandIRS-1gene expression. The extract may also play a role in alleviating inflammation by reducing TNF-α expression, suggesting that additional experiments are required for its development as a suitable therapeutic option against NAFLD. Importantly, further research is needed to explore its antioxidant role in this model.

Type 2 diabetes (T2D) is characterized by pancreatic beta-cell dysfunction, increased cell death and loss of beta-cell mass despite chronic treatment. Consequently, there has been growing interest in developing beta cell-centered therapies. Beta-cell regeneration is mediated by augmented beta-cell proliferation, transdifferentiation of other islet cell types to functional beta-like cells or the reprograming of beta-cell progenitors into fully differentiated beta cells. This mediation is orchestrated by beta-cell differentiation transcription factors and the regulation of the cell cycle machinery. This review investigates the beta-cell regenerative potential of antidiabetic plant extracts and phytochemicals. Various preclinical studies, including in vitro, in vivo and ex vivo studies, are highlighted. Further, the potential regenerative mechanisms and the intra and extracellular mediators that are of significance are discussed. Also, the potential of phytochemicals to translate into regenerative therapies for T2D patients is highlighted, and some suggestions regarding future perspectives are made.

Wastewater surveillance of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has shown to be an important approach to determine early outbreaks of infections. Wastewater-based epidemiology (WBE) is regarded as a complementary tool for monitoring SARS-CoV-2 trends in communities. In this study, the changes in the SARS-CoV-2 RNA levels in wastewater during Easter holidays in 2021 and 2022 in the City of Cape Town were monitored over nine weeks. Our findings showed a statistically significant difference in the SARS-CoV-2 RNA viral load between the study weeks over the Easter period in 2021 and 2022, except for study week 1 and 4. During the Easter week, 52% of the wastewater treatment plants moved from the lower (low viral RNA) category in 2021 to the higher (medium to very high viral RNA) categories in 2022. As a result, the median SARS-CoV-2 viral loads where higher during the Easter week in 2022 than Easter week in 2021 (p = 0.0052). Mixed-effects model showed an association between the SARS-CoV-2 RNA viral loads and Easter week over the Easter period in 2021 only (p < 0.01). The study highlights the potential of WBE to track outbreaks during the holiday period.

Diabetes, a prevalent metabolic condition with a wide range of complications, is fast becoming a global health crisis. Herbal medicine and enhanced extracts are some of the therapeutic options used in the management of diabetes mellitus. The plant-derived molecules and their suitable structure modification have given many leads or drugs to the world such as metformin used as an antidiabetic drug. The stem extract of Sclerocarya birrea has been reported as a potent antidiabetic (glucose uptake) agent. However, the bioactive compounds have not been reported from S. birrea for treatment of diabetes. In this study, the spray-dried aqueous leaf extracts of S. birrea were investigated as an antidiabetic agent using a 2-deoxy-glucose (2DG) technique showing good stimulatory effect on glucose uptake in differentiated C2C12 myocytes with % 2DG uptake ranging from 110–180% that was comparable to the positive control insulin. Three compounds were isolated and identified using bioassay-guided fractionation of the spray-dried aqueous extract of S. birrea leaves: myricetin (1), myricetin-3-O-β-D-glucuronide (2) and quercetin-3-O-β-D-glucuronide (3). Their chemical structures were determined using NMR and mass spectrometric analyses, as well as a comparison of experimentally obtained data to those reported in the literature. The isolated compounds (1–3) were studied for their stimulatory actions on glucose uptake in differentiated C2C12 myocytes. The three compounds (1, 2 and 3) showed stimulatory effects on the uptake of 2DG in C2C12 myocytes with % 2DG uptake ranging from 43.9–109.1% that was better compared to the positive control insulin. Additionally, this is the first report of the flavonoid glycosides (myricetin-3-O-β-D-glucuronide) for antidiabetic activity and they are the main bioactive compound in the extract responsible for the antidiabetic activity. This result suggests that the S. birrea leaves have the potential to be developed for treatment of diabetes.