Evaluation of the phytoestrogenic activity of Cyclopia genistoides (honeybush) methanol extracts and relevant polyphenols

The original publication is available at http://pubs.acs.org/Unfermented C. genistoides methanol extracts of different harvestings and selected polyphenols were evaluated for phytoestrogenic activity by comparing binding to both ER subtypes, transactivation of an ERE-containing promoter reporter, proliferation of MCF-7-BUS and MDA-MB-231 breast cancer cells, and binding to SHBG. The extracts from one harvesting of C. genistoides (P104) bound to both ER subtypes. All extracts transactivated ERE-containing promoter reporters via ERβ but not via ERα. All extracts, except P122, caused proliferation of the estrogen-sensitive MCF-7-BUS cells. Proliferation of MCF-7-BUS cells was ER-dependent as ICI 182,780 reversed proliferation. Physiologically more relevant, extracts antagonized E2-induced MCF-7-BUS cell proliferation. Furthermore, all extracts, except P122, induced proliferation of the estrogen-insensitive MDA-MB-231 cells, suggesting that the extracts are able to induce ER-dependent and ER-independent cell proliferation. Binding to SHBG by extracts was also demonstrated. These results clearly show that C. genistoides methanol extracts display phytoestrogenic activity and act predominantly via ERβ. HPLC and LC-MS analysis, however, suggests that the observed phytoestrogenic activity cannot be ascribed to polyphenols known to be present in other Cyclopia species. © 2007 American Chemical Society.Publishers' versio

Value of antioxidant capacity as relevant assessment tool for “health benefits” of fruit - understated or inflated?

CITATION: Joubert, E. & Gelderblom, W. 2016. Value of antioxidant capacity as relevant assessment tool for “health benefits” of fruit - understated or inflated?. South African Journal of Clinical Nutrition, 29(4):4-6.The original publication is available at http://www.sajcn.co.zaConsumption of fruit and vegetables is considered to be an inherent part of a healthy diet, but more so since plant antioxidants, and in particular polyphenols, have been linked through in vivo and epidemiological studies with positive health outcomes.1–3 As a result, polyphenols have been elevated to “lifespan essentials”, because scientific evidence indicated that they are needed by humans to achieve a full lifespan by reducing the risk of a range of chronic diseases.4 No Dietary Reference Intake values exist for polyphenols, however, it has been suggested that their target intake value should be based on the total polyphenol content provided by the “5-a-day” portions of fruit and vegetables recommendation by the World Health Organisation.http://www.sajcn.co.za/index.php/SAJCN/article/view/1178Publisher's versio

In vitro a-glucosidase inhibition by honeybush (Cyclopia genistoides) food ingredient extract-potential for dose reduction of acarbose through synergism

CITATION: Miller, N.; Malherbe, C. J. & Joubert, E. 2020. In vitro α-glucosidase inhibition by honeybush (Cyclopia genistoides) food ingredient extract—potential for dose reduction of acarbose through synergism. Food and Function, 11:6476–6486. doi:10.1039/d0fo01306dThe original publication is available at http://pubs.rsc.org/en/Journals/Journal/FOExtracts of Cyclopia species are used as food ingredients. In vitro α-glucosidase (AG) inhibition by ultrafiltered C. genistoides extract, fractions enriched in xanthones (XEF) and benzophenones (BEF), as well as mangiferin, isomangiferin, 3-β-D-glucopyranosyliriflophenone (I3G) and 3-β-D-glucopyranosyl-4-O-β-D-glucopyranosyliriflophenone (IDG) was determined with acarbose as positive control. XEF was more potent than the extract and BEF (IC50 = 43.3, 95.5 and 205.7 μg mL−1, respectively). Compounds demonstrated potency in the descending order: acarbose (IC50 = 44.3 μM) > mangiferin (102.2 μM) > isomangiferin (119.8 μM) > I3G (237.5 μM) > IDG (299.4 μM). The combination index (CI) was used to determine synergism (CI six-fold) across all effect levels were calculated for combinations of acarbose with mangiferin or isomangiferin, explaining the greater acarbose dose reduction potential of XEF vs. BEF. The effect of batch-to-batch variation (n = 10) of raw plant material on AG inhibition was quantified at a fixed concentration (160 μg mL−1). XEFs (xanthone content = 223–481 g kg−1) achieved AG inhibition of 63–72%, whereas BEFs (benzophenone content = 114–251 g kg−1) achieved AG inhibition of 26–34%, with weak linear correlation (R2 < 0.43) between target compound content of the fractions and their achieved AG inhibition. Thus, extract fractions of C. genistoides, enriched in xanthones and benzophenones, show potential in reducing the effective dose of acarbose required to prevent postprandial hyperglycaemia.https://pubs.rsc.org/en/content/articlelanding/2020/fo/d0fo01306dPublishers versio

Germline sequence variants contributing to cancer susceptibility in South African breast cancer patients of African ancestry

Since the discovery of the breast cancer susceptibility genes, BRCA1 and BRCA2, various other genes conferring an increased risk for breast cancer have been identified. Studies to evaluate sequence variants in cancer predisposition genes among women of African ancestry are limited and mostly focused on BRCA1 and BRCA2. To characterize germline sequence variants in cancer susceptibility genes, we analysed a cohort of 165 South African women of self-identified African ancestry diagnosed with breast cancer, who were unselected for family history of cancer. With the exception of four cases, all others were previously investigated for BRCA1 and BRCA2 deleterious variants, and were negative for pathogenic variants. We utilized the Illumina TruSight cancer panel for targeted sequencing of 94 cancer susceptibility genes. A total of 3.6% of patients carried a pathogenic/likely pathogenic variant in a known breast cancer susceptibility gene: 1.2% in BRCA1, 0.6% in each of BRCA2, ATM, CHEK2 and PALB, none of whom had any family history of breast cancer. The mean age of patients who carried deleterious variant in BRCA1/BRCA2 was 39 years and 8 months compared to 47 years and 3 months among women who carried a deleterious variant in other breast cancer susceptibility genes.The University of Pretoria, Genomics Research Institute, the Cancer Association of South Africa, the South African Medical Research Council and the South African National Research Foundation.https://www.nature.com/srepBiochemistryGeneticsMicrobiology and Plant Patholog

Axial variation of wetting efficiency and liquid-solid mass transfer in long trickle bed columns

The wetting efficiency and solid liquid mass transfer coefficient was measured separately and simultaneously using the electrochemical cell technique while varying the superficial liquid velocity and hydrodynamic state of the column by using different pre-wetting procedures. The wetting efficiency in columns with an aspect ratio - distance from distributor divided by column diameter – of up to 33, decreased with distance from the distributor regardless of the hydrodynamic state of the column. Although the solid liquid mass transfer coefficient also decreased with an increase in axial position, this decrease was much more significant where the pre-wetting procedure that resulted in a lower overall wetting efficiency was used. When a pre-wetting procedure that resulted in a higher average wetting efficiency was used, the liquid solid mass transfer coefficient was much less dependent on liquid velocity and only a relatively small decrease with axial position was observed. The results highlight the difference in surface renewal processes that is possible between columns operated at the same conditions but under different hydrodynamic states and emphasise the importance of hydrodynamic multiplicity when liquid redistribution is considered.http: pubs.acs.org/IECRhb201

Diversity and molecular barcoding of stink bugs (Hemiptera: Pentatomidae) associated with macadamia in South Africa

Stink bugs are major pests of macadamia in South Africa. Accurate identification and knowledge of species composition are important to inform management practices. The overall aims of this study were to identify stink bug species from macadamia orchards in South Africa using morphology, and to establish a DNA database based on the cytochrome c oxidase subunit 1 gene region. A total of 21 stink bug species were found in macadamia orchards in KwaZulu-Natal, Limpopo and Mpumalanga provinces. Bathycoelia distincta Distant, 1878, was the dominant species throughout all three growing regions. Two unidentified species of Boerias Kirkaldy, 1909, here designated as Boerias sp. 1 and Boerias sp. 2, were the second and third most abundant species found in KwaZulu-Natal. No species of Boerias has previously been reported in association with macadamia. Evidence of a cryptic third species of Boerias was also found. Species composition fluctuated over three growing seasons in Limpopo and differed between the three growing regions during the 2019–2020 season, highlighting the need for ongoing monitoring of these important pest species. The DNA barcode database developed in this study will be valuable for future monitoring and identifications, including cryptic or polymorphic stink bug species and different life stages.SUPPLEMENTARY MATERIALS : Table S1: Number of stink bug morphospecies found at each location across three seasons; Table S2: Seasonal presence of stink bug species per scout batch per region; Table S3: Collection details of specimens sequenced to determine species presence and composition of stink bugs in macadamia orchards in South Africa.DATA AVAILABILITY STATEMENT : Sequence data openly available in Genbank (www.ncbi.nlm.nih.gov) (accessed on 27 January 2022).The University of Pretoria, the Forestry and Agricultural Biotechnology Institute (FABI), the DSI-NRF Centre of Excellence in Plant Health Biotechnolog), Macadamias South Africa NPC (SAMAC) and NRF Thuthuka.https://www.mdpi.com/journal/insectsBiochemistryForestry and Agricultural Biotechnology Institute (FABI)GeneticsMicrobiology and Plant PathologyZoology and Entomolog

Towards gaining a competitive advantage : the relationship between burnout, job satisfaction, social support and mindfulness

The prevalence of burnout has increased in the past 30 years. A review of the literature suggested that burnout could be prevented through the application of interpersonal as well as intrapersonal strategies. Interpersonal strategies consist of employees having access to social support systems and human resources management’s ability that may have a positive influence on job satisfaction. Intrapersonal strategies take the form of training individuals to become mindful, thus being aware of their physical as well as psychological states. Little research has been conducted on the successfulness of such strategies and the need was identified to explore the relationship between burnout, job satisfaction, social support and mindfulness among employees in a South African corporate organisation. The purpose of this study was to determine the relationship between burnout, job satisfaction, social support and mindfulness within a South African corporate organisation. The study was a quantitative study and a correlational research design was used. Systematic random sampling was used to compile the sample. The sample consisted of 209 employees working in a financial corporate environment in Johannesburg. Pearson correlation coefficients were computed for burnout, job satisfaction, social support and mindfulness. Moderate to strong inverse correlations were discovered among the constructs under investigation. Thereafter, a multiple regression analysis was deemed necessary to determine which of the independent variables (mindfulness, job satisfaction and social support) contributed significantly to explaining the variance in burnout scores. All the constructs (job satisfaction, mindfulness and social support) appear to be significant predictors of burnout. Job satisfaction displayed the highest beta value whilst mindfulness scored the second highest beta value in the multiple regression analysis.http://www.journals.co.za/ej/ejour_jcman.htm

Model development for predicting in vitro bio-capacity of green rooibos extract based on composition for application as screening tool in quality control

CITATION: Viraragavan, A. et al. 2020. Model development for predicting in vitro bio-capacity of green rooibos extract based on composition for application as screening tool in quality control. Food & Function, 11:3084-3094. doi:10.1039/C9FO02480HThe original publication is available at http://pubs.rsc.org/en/Journals/Journal/FOMounting evidence of the ability of aspalathin to target underlying metabolic dysfunction relevant to the development or progression of obesity and type 2 diabetes created a market for green rooibos extract as a functional food ingredient. Aspalathin is the obvious choice as a chemical marker for extract standardisation and quality control, however, often the concentration of a single constituent of a complex mixture such as a plant extract is not directly related to its bio-capacity, i.e. the level of in vitro bioactivity effected in a cell system at a fixed concentration. Three solvents (hot water and two EtOH–water mixtures), previously shown to produce bioactive green rooibos extracts, were selected for extraction of different batches of rooibos plant material (n = 10). Bio-capacity of the extracts, tested at 10 μg ml−1, was evaluated in terms of glucose uptake by C2C12 and C3A cells and lipid accumulation in 3T3-L1 cells. The different solvents and inter-batch plant variation delivered extracts ranging in aspalathin content from 54.1 to 213.8 g kg−1. The extracts were further characterised in terms of other major flavonoids (n = 10) and an enolic phenylpyruvic acid glucoside, using HPLC-DAD. The 80% EtOH–water extracts, with the highest mean aspalathin content (170.9 g kg−1), had the highest mean bio-capacity in the respective assays. Despite this, no significant (P ≥ 0.05) correlation existed between aspalathin content and bio-capacity, while the orientin, isoorientin and vitexin content correlated moderately (r ≥ 0.487; P < 0.05) with increased glucose uptake by C2C12 cells. Various multivariate analysis methods were then applied with Evolution Program-Partial Least Squares (EP-PLS) resulting in models with the best predictive power. These EP-PLS models, based on all quantified compounds, predicted the bio-capacity of the extracts for the respective cell types with RMSECV values ≤ 11.5, confirming that a complement of compounds, and not aspalathin content alone, is needed to predict the in vitro bio-capacity of green rooibos extracts. Additionally, the composition of hot water infusions of different production batches of green rooibos (n = 29) at ‘cup-of-tea’ equivalence was determined to relate dietary supplementation with the extract to intake in the form of herbal tea.Publishers versio

Cardiovascular health risk among university students in South Africa

Tradisioneel is individue se vermoëns, belangstellings en persoonlikhede tydens beroepsvoorligting en werwings- en keuringsprosesse geassesseer, terwyl slegs enkele studies op die liggaamlike gesondheid van tweedejaarstudente, as intreevlakwerknemers vir sakeondernemings in Suid- Afrika, gefokus het. Die hoofdoel van hierdie navorsing was om die stand van die kardiovaskulêre gesondheid van universiteitstudente in hul tweede jaar (as intreevlakwerknemers) te bepaal. Die motivering vir die studie was tweeledig: eerstens om die huidige kardiovaskulêre gesondheidsrisiko van studente te bepaal, en tweedens om hulle in te lig oor die mate van risiko waaraan hulle blootgestel is. Die studie was ’n kwantitatiewe deursneestudie wat onderneem is om inligting in te win oor die kardiovaskulêre gesondheid van universiteitstudente. Die steekproef wat vir hierdie navorsingstudie gebruik is, het bestaan uit 162 universiteitstudente in Suid-Afrika wat almal tussen 18 en 25 jaar oud was. Die resultate het aangedui dat 55.6% van die betrokke studente aan hoë bloeddruk gely het. Uit laasgenoemde groep studente is 81.1% as prehipertensief gediagnoseer, terwyl stadium 1-hipertensie by 18.9% gediagnoseer is. Altesaam 64.8% van al die deelnemende studente se tellings is in die hoër meetgebied van die Kardiale Stresindeks (KSI). Ongelukkig het 61% van dié studente met verhoogde KSI-tellings ook hoë bloeddruk getoon. Benewens verhoogde harttempo en bloeddruk het 15.2% van die deelnemers ook swak harttempoveranderlikheid getoon. Dus het byna 10% van die totale steekproef verhoogde kardiale stresvlakke, verhoogde harttempo en hoë bloeddrukvlakke vertoon. Die resultate dui daarop dat universiteitstudente heeltemal onbewus is van hul kardiovaskulêre gesondheid en van die moontlikheid dat dit ’n invloed op hul loopbane kan hê. Beroepsvoorligters, industriële sielkundiges, opvoedkundige sielkundiges en praktisyns op die gebied van menslikehulpbronbestuur kan hierdie inligting voordelig binne die bestek van hul praktyk gebruik om beroepsvoorligting aan fisiologiestudente te verskaf. Dié praktiese benadering sal fisiologiestudente ook in staat stel om vas te stel wat hul eie kardiovaskulêregesondheidsrisiko’s is.Traditionally, individuals’ abilities, interests and personality were assessed during career guidance and recruitment and selection processes; however, only a few studies focused on the actual health of second-year students, as entry-level employees for business in South Africa. The main research purpose was to determine the cardiovascular health of second-year university students’ (as young entry-level employees). The motivations for the study are two-fold: to determine the current cardiovascular health risk of students, and to educate the students about such risk. The study was a quantitative cross-sectional study to determine university students’ cardiovascular health. The sample used in this research study consisted of 162 university students in South Africa, between the ages of 18 and 25 years. The results indicated that 55.6% students had high blood pressure. Then 81.1% of the latter group of students were identified as prehypertensive, while 18.9% were considered as having stage-1 hypertension. Students exhibited elevated cardiac stress as well. Altogether 64.8% of all the participating students scored in the elevated range of the Cardiac Stress Index (CSI). Unfortunately, 61% of the students with elevated CSI readings also exhibited high blood pressure. Furthermore, of the latter group, 15.2% exhibited poor heart rate variability, as well as elevated heart rate and blood pressure. Therefore, nearly 10% of the total sample exhibited elevated cardiac stress, an elevated heart rate and high blood pressure levels. The implications of the results are that university students are unaware of their cardiovascular health and that it may have an effect on their careers. Career counsellors, industrial psychologists, educational psychologists, and human resource management practitioners may benefit from this information in their scope of practice to guide physiology students in their career. This practical approach also allows physiology students to determine their own cardiovascular health risks.http://www.satnt.ac.zaam201