Verification of the folkloric and anecdotal antidiabetic effects of Hypoxis hemerocallidea (Fisch., CA Mey. & Ave-Lall) and isolated, beta-sitosterol using early-stage type II spontaneous diabetic mutant BKS-Lepr(db) mice

BACKGROUND : Previous studies in our laboratory in ex vivo assays have demonstrated H. hemerocallidea extract as potential antidiabetic agent through increased insulin release from pancreatic beta cells. Thus, for this study the early stage type II spontaneous diabetic mutant mice model was used to evaluate and determine the degree of the antidiabetic efficacy of H. hemerocallidea. METHODS : Eight-weeks-old type II spontaneous pre-diabetic mutant BKS-Leprdb mice were fed with feed supplemented with either H. hemerocallidea extract, isolated compound (β-sitosterol) or chlorpropamide (positive control) for 4 weeks. The haematological parameters, clinical chemistry, glucose tolerance, feed intake, faecal output and body weights were measured. RESULTS : The blood glucose concentrations of all the animals treated with plant extract, β-sitosterol compound and non-treated pre-diabetic animals did not return to baseline levels. Only the β-sitosterol treatment and positive control groups resulted in a respective small decrease of 5.8 and 5.2% in the mouse weights over the study period, with no significant changes (p > 0.05) in food intake. However, there was a general trend for decrease in faecal output for all the groups. Albumin, triglycerides, and total cholesterol levels in β-sitosterol and chlorpropamide-treated animals were lower, relative to untreated-animals. Animals fed with plant extract showed large amounts of internal fat. There were no significant changes (p > 0.05) in total serum protein, globulin, alanine aminotransferase, alkaline phosphatase, urea nitrogen and creatinine attributed to administration of treatments. In all groups, some animals showed lesions associated with cardiac puncture. Few animals except animals treated with plant extract, showed presence of a leftventricular hypertrophic cardiomyopathy. The liver and kidneys for all groups appeared macroscopically normal and the thymuses were small (±2 mg). There were pathological signs in some of the animals particularly in myocardial fibres, renal tubular, glomerular, hepatocyte granularity and pancreas islets. However, there was no significance trend between the groups. CONCLUSION : Based on the results, none of the treatments could be considered highly effective for the management of type II pre-diabetes as sole therapeutic intervention.The Department of Higher Education and training (DHET) Research Development Grant (RDG) and Faculty of Veterinary Science University of Pretoria.https://bmccomplementmedtherapies.biomedcentral.comam2023Paraclinical Science

Anti-diabetic activity of extracts and a bioactive compound isolated from Hypoxis hemerocallidea (Hypoxidaceae) in a murine model of spontaneous diabetes

A previous study investigated and demonstrated that Hypoxis hemerocallidea (Fisch and Mey) (Hypoxidaceae) corm extracts used traditionally, stimulated insulin secretion from pancreatic _ cells maintained under ex vivo conditions. The effect was also related to the antioxidant activity of extracts. In order to find leads with unique chemical structures which may exert a hitherto unexploited mode of action, phytochemical investigation on extracts of the plant was carried out. This involved the following steps: authentication and extraction of the plant material, separation and isolation of the constituents of interest, characterization of the isolated compounds and quantitative evaluation. Furthermore, the following study also followed the normal sequence of principles of replacement, in that all necessary non-animal and ex vivo animal models were first to optimise evaluation of the product, before testing using a mouse model. With H. hemerocallidea being traditionally used as wild bulbs, we firstly ascertained the risk of this tradional use with specific focus on heavy metals. This is important as certain soil minerals are known to increase antioxidant capacity in plants, and associated extracts, as a stress response to soil heavy metal content. However, the use of these wild plants may pose a safety concern to the person consuming the plant as a result of their potential heavy metal content. Corms collected from the wild from five different geographical regions of South Africa, were evaluated for their concentration of metal concentrations and associated antioxidant activity. Among the trace metals investigated, iron was the highest, for the corm collected from Ga-rankuwa. No link was found between the corm’s antioxidant activity and environmental conditions. We further investigated the corm from Ga-rankuwa, since it had the highest antioxidant activity for its anti-diabetic activity. Assays included glucose uptake in C2C12 myocytes, 3T3-L1 preadipocytes and insulin secretion in rat insulinoma RiNm5F cells in total five different fractions and three compounds isolated. Only the methanol crude extract, fraction III & V and isolated _-sitosterol significantly increased insulin release and lowered blood glucose levels both in C2C12 myocytes and 3T3-L1 preadipocytes to a degree. All the crude extracts, fractions and tested compounds had relatively low cytotoxicity against all the diabetic cell lines used. In the final study we determined the effect of H. hemerocallidea and its isolated compound, _-sitosterol in a murine mouse model of spotaneous diabetes. The _-sitosterol induced slight weight loss in the mice and stabilised blood glucose concentration after the 4 weeks treatment course. No changes in the haematology were evident while clinical chemistry evaluations showed slight treatment-related changes in triglycerides and total cholesterol. The study concludes that H. Hemerocallidae was not a suitable as a sole treatment agent in the management of diabetes. However it holds promise as an add-on treatment to lifestyle intervention for the management of type-II diabetes.Thesis (PhD)--University of Pretoria, 2019.Paraclinical SciencesPhDUnrestricte

Soil parameters affecting the antioxidant activity of Hypoxis hemerocallidea corm extracts in different areas of South Africa

Hypoxis hemerocallidea is wild harvested and widely used due inter alia to its strong antioxidant activity. Antioxidant activity is linked to plant stressors like soil heavy metals concentrations and pH. If high antioxidant activity is caused by heavy metals stressing the plant, the plant may not be completely safe. Soils and H. hemerocallidea corms were collected from five different geographical regions of South Africa. The highest corm and soil heavy metals concentration were Fe, Mn and Cr, with Fe having the highest, particularly for corms collected from Ga-rankuwa (83.7 ± 0.03 μg/g). The soil and corm samples from Ga-rankuwa with high levels of metals (Fe, Cr, Ni, Pb) had greater antioxidant activity (EC50 of 1.68 ± 0.49 μg/mL). Despite corms showing ability to bio-accumulate heavy metals, the antioxidant activity could not be linked to environmental conditions. The results highlight potential danger of using naturally harvested bulbs growing in unidentified soils.http://www.asianjournalofchemistry.co.inpm2021Paraclinical Science

Metabolomics approach for predicting stomach and colon contents in dead Arctocephalus pusillus pusillus, Arctocephalus tropicalis, Lobodon carcinophaga and Ommatophoca rossii from sub-Antarctic region.

The dietary habits of seals play a pivotal role in shaping management and administration policies, especially in regions with potential interactions with fisheries. Previous studies have utilized various methods, including traditional approaches, to predict seal diets by retrieving indigestible prey parts, such as calcified structures, from intestines, feces, and stomach contents. Additionally, methods evaluating nitrogen and stable isotopes of carbon have been employed. The metabolomics approach, capable of quantifying small-scale molecules in biofluids, holds promise for specifying dietary exposures and estimating disease risk. This study aimed to assess the diet composition of five seal species-Arctocephalus pusillus pusillus, Lobodon carcinophaga, Ommatophoca rossii, and Arctocephalus tropicalis 1 and 2-by analyzing stomach and colon contents collected from stranded dead seals at various locations. Metabolite concentrations in the seal stomach and colon contents were determined using Nuclear Magnetic Resonance Spectroscopy. Among the colon and stomach contents, 29 known and 8 unknown metabolites were identified. Four metabolites (alanine, fumarate, lactate, and proline) from stomach contents and one metabolite (alanine) from colon contents showed no significant differences between seal species (p>0.05). This suggests that traces of these metabolites in the stomach and colon contents may be produced by the seals' gut microbiome or derived from other animals, possibly indicating reliance on fish caught at sea. Despite this insight, the cause of death for stranded seals remains unclear. The study highlights the need for specific and reliable biomarkers to precisely indicate dietary exposures across seal populations. Additionally, there is a call for the development of relevant metabolite and disease interaction networks to explore disease-related metabolites in seals. Ultimately, the metabolomic method employed in this study reveals potential metabolites in the stomach and colon contents of these seal species

Molecular Docking and Molecular Dynamics Studies of Antidiabetic Phenolic Compound Isolated from Leaf Extract of Englerophytum magalismontanum (Sond.) T.D.Penn.

Englerophytum magalismontanum, a medicinal plant with ethnopharmacology use, has a dearth of information regarding its antidiabetic properties. This study evaluated the crude methanol leaf extract of E. magalismontanum and its fractions for total phenolic content, antioxidant activity, and digestive enzymes (α-amylase and α-glucosidase) inhibitory activity using standard methods. The total phenolic content (56.53 ± 1.94 mg GAE/g dry extract) and DPPH Trolox antioxidant equivalent (TAE) (1.51 ± 0.66 µg/mL) of the methanol fraction were the highest among the fractions. The IC50 values of the methanol fraction against α-amylase (10.76 ± 1.33 µg/mL) and α-glucosidase (12.25 ± 1.05 µg/mL) activities were also high. Being the most active, the methanol fraction was subjected to bio-assay guided column chromatography-based enzyme inhibition to obtain a pure compound. The phenolic compound isolated and identified as naringenin inhibited α-amylase and α-glucosidase with IC50 of 5.81 ± 2.14 µg/mL and 4.77 ± 2.99 µg/mL, respectively. This is the first study to isolate naringenin from E. magalismontanum extract. The molecular docking and molecular dynamics studies demonstrated naringenin as a promising lead compound in comparison to acarbose for the treatment of diabetes through the inhibition of α-glucosidase activity

Identification of South African Plant-Based Bioactive Compounds as Potential Inhibitors against the SARS-CoV-2 Receptor

The expected progress in SARS-CoV-2 vaccinations, as anticipated in 2020 and 2021, has fallen short, exacerbating global disparities due to a lack of universally recognized “safe and effective” vaccines. This study focuses on extracts of South African medicinal plants, Artemisia annua and Artemisia afra, to identify metabolomic bioactive compounds inhibiting the binding of the SARS-CoV-2 spike protein to ACE2 receptors. The extracts were monitored for cytotoxicity using a resazurin cell viability assay and xCELLigence real-time cell analyzer. Chemical profiling was performed using UPLC-MS/MS, orthogonal projection to latent structures (OPLS), and evaluated using principle component analysis (PCA) models. Identified bioactive compounds were subjected to in vitro SARS-CoV-2 enzyme inhibition assay using standard methods and docked into the spike (S) glycoprotein of SARS-CoV-2 using Schrodinger® suite followed by molecular dynamics simulation studies. Cell viability assays revealed non-toxic effects of extracts on HEK293T cells at lower concentrations. Chemical profiling identified 81 bioactive compounds, with compounds like 6″-O-acetylglycitin, 25-hydroxyvitamin D3-26,23-lactone, and sesaminol glucoside showing promising binding affinity. Molecular dynamics simulations suggested less stable binding, but in vitro studies demonstrated the ability of these compounds to interfere with SARS-CoV-2 spike protein’s binding to the human ACE2 receptor. Sesaminol glucoside emerged as the most effective inhibitor against this interaction. This study emphasizes the importance of multiplatform metabolite profiling and chemometrics to understand plant extract composition. This finding is of immense significance in terms of unravelling metabolomics bioactive compounds inhibiting the binding of the SARS-CoV-2 spike protein to ACE2 receptors and holds promise for phytotherapeutics against SARS-CoV-2