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Pretorius L, Smith C. Translation of preclinical ethnomedicine data in LMICs: the example of rooibos. Front Pharmacol 2023; 14:1328828. [PMID: 38174224 PMCID: PMC10763253 DOI: 10.3389/fphar.2023.1328828] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/07/2023] [Indexed: 01/05/2024] Open
Abstract
All disease, but especially non-communicable diseases, are related to dysfunction of one or more regulatory systems. In developing countries, long-term management of patients with chronic diseases has many challenges and is generally not financially viable, but Africa in particular, which is rich in diverse ethnomedicines presents a more feasible long-term therapeutic approach in this niche. However, despite comprehensive preclinical investigations on numerous plant-derived candidate medicines, only a small portion of these reach the patient as recognised medicines. In this review, we use the example of rooibos (Aspalathus linearis (Burm.f.) R. Dahlgren)-which is globally consumed as aromatic, caffeine-free tea-to illustrate the hurdles that need to be overcome in the low-to middle-income countries, before progression of ethnomedicines to official treatment regimens can be achieved. In terms of methodology, regulatory system focused rooibos papers indexed on PubMed for the past three decades (n = 112) were accessed. Papers reporting duplication of previous results were excluded, as well as review papers. Topics covered includes the high standard of ethnomedicine drug discovery and efficacy testing research performed in Africa (and South Africa in particular in the case of rooibos), the potential bias in terms of preclinical research focus, ethnomedicine ownership and the requirement for independent clinical trial coordination and/or management.
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Affiliation(s)
| | - Carine Smith
- Experimental Medicine, Department of Medicine, Faculty of Medicine and Health Sciences, Stellenbosch University, Cape Town, South Africa
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2
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Abdul NS, Marnewick JL. What Has Been the Focus of Rooibos Health Research? A Bibliometric Overview. J Herb Med 2022. [DOI: 10.1016/j.hermed.2022.100615] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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3
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Lisitsyna A, Moritz F, Liu Y, Al Sadat L, Hauner H, Claussnitzer M, Schmitt-Kopplin P, Forcisi S. Feature Selection Pipelines with Classification for Non-targeted Metabolomics Combining the Neural Network and Genetic Algorithm. Anal Chem 2022; 94:5474-5482. [PMID: 35344349 DOI: 10.1021/acs.analchem.1c03237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Non-targeted metabolomics via high-resolution mass spectrometry methods, such as direct infusion Fourier transform-ion cyclotron resonance mass spectrometry (DI-FT-ICR MS), produces data sets with thousands of features. By contrast, the number of samples is in general substantially lower. This disparity presents challenges when analyzing non-targeted metabolomics data sets and often requires custom methods to uncover information not always accessible via classical statistical techniques. In this work, we present a pipeline that combines a convolutional neural network with traditional statistical approaches and an adaptation of a genetic algorithm. The developed method was applied to a lifestyle intervention cohort data set, where subjects at risk of type 2 diabetes underwent an oral glucose tolerance test. Feature selection is the final result of the pipeline, achieved through classification of the data set via a neural network, with a precision-recall score of over 0.9 on the test set. The features most relevant for the described classification were then chosen via a genetic algorithm. The output of the developed pipeline encompasses approximately 200 features with high predictive scores, providing a fingerprint of the metabolic changes in the prediabetic class on the data set. Our framework presents a new approach which allows to apply complex modeling based on convolutional neural networks for the analysis of high-resolution mass spectrometric data.
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Affiliation(s)
- Anna Lisitsyna
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg 85764, Germany.,German Center for Diabetes Research (DZD), Neuherberg 85764, Germany
| | - Franco Moritz
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg 85764, Germany
| | - Youzhong Liu
- Analytical Development, Small Molecule Development, Janssen Pharmaceutical Companies of Johnson and Johnson, Beerse 2340, Belgium
| | - Loubna Al Sadat
- Institute for Nutritional Medicine, School of Medicine, Technical University of Munich, Munich 80686, Germany
| | - Hans Hauner
- Institute for Nutritional Medicine, School of Medicine, Technical University of Munich, Munich 80686, Germany.,Else Kröner-Fresenius-Centre for Nutritional Medicine, School of Life Sciences, Technical University of Munich, Freising 85354, Germany
| | - Melina Claussnitzer
- Broad Institute of MIT and Harvard, Cambridge 02141-2023 Massachusetts, United States.,Division of Gerontology, Department of Medicine, Beth Israel Deaconess Medical Center, Boston, Massachusetts 02108, United States.,Harvard Medical School, Harvard University, Boston, Massachusetts 02108, United States
| | - Philippe Schmitt-Kopplin
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg 85764, Germany.,Chair of Analytical Food Chemistry, TUM School of Life Sciences, Technical University Munich, Munich 80686, Germany
| | - Sara Forcisi
- Research Unit Analytical BioGeoChemistry, Helmholtz Zentrum München, Neuherberg 85764, Germany.,German Center for Diabetes Research (DZD), Neuherberg 85764, Germany
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Pringle NA, van de Venter M, Koekemoer TC. Comprehensive in vitro antidiabetic screening of Aspalathus linearis using a target-directed screening platform and cellomics. Food Funct 2021; 12:1020-1038. [PMID: 33416070 DOI: 10.1039/d0fo02611e] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The antidiabetic potential of Aspalathus linearis has been investigated for over a decade, however, its characterisation remains incomplete with results scattered across numerous journals making the information difficult to compare and integrate. To explore whether any potential antidiabetic mechanisms for A. linearis have been neglected and to compare the suitability of extracts of green and "fermented" A. linearis as potential antidiabetic treatment strategies, this study utilised a comprehensive in vitro antidiabetic target-directed screening platform in combination with high content screening and analysis/cellomics. The antidiabetic screening platform consisted of 20 different screening assays that incorporated 5 well-characterised antidiabetic targets i.e. the intestine, liver, skeletal muscle, adipose tissue/obesity and pancreatic β-cells. Both the green and fermented extracts of A. linearis demonstrated very broad antidiabetic mechanisms as they revealed several promising activities that could be useful in combatting insulin resistance, inflammation, oxidative stress, protein glycation and pancreatic β-cell dysfunction and death - with a strong tendency to attenuate postprandial hyperglycaemia and the subsequent metabolic dysfunction which arises as a result of poor glycaemic control. The green extract was more successful at combatting oxidative stress in INS-1 pancreatic β-cells and enhancing intracellular calcium levels in the absence of glucose. Conversely, the fermented extract demonstrated a greater ability to inhibit α-glucosidase activity as well as palmitic acid-induced free fatty acid accumulation in C3A hepatocytes and differentiated L6 myotubes, however, further studies are required to clarify the potentially toxic and pro-inflammatory nature of the fermented extract.
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Affiliation(s)
- Nadine A Pringle
- Department of Biochemistry and Microbiology, Nelson Mandela University, Port Elizabeth, South Africa.
| | - Maryna van de Venter
- Department of Biochemistry and Microbiology, Nelson Mandela University, Port Elizabeth, South Africa.
| | - Trevor C Koekemoer
- Department of Biochemistry and Microbiology, Nelson Mandela University, Port Elizabeth, South Africa.
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Viraragavan A, Hlengwa N, de Beer D, Riedel S, Miller N, Bowles S, Walczak B, Muller C, Joubert E. Model development for predicting in vitro bio-capacity of green rooibos extract based on composition for application as screening tool in quality control. Food Funct 2020; 11:3084-3094. [PMID: 32195502 DOI: 10.1039/c9fo02480h] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Mounting 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.
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Affiliation(s)
- Amsha Viraragavan
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg 7505, South Africa.
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Layman JI, Pereira DL, Chellan N, Huisamen B, Kotzé SH. A histomorphometric study on the hepatoprotective effects of a green rooibos extract in a diet-induced obese rat model. Acta Histochem 2019; 121:646-656. [PMID: 31153588 DOI: 10.1016/j.acthis.2019.05.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2018] [Revised: 05/21/2019] [Accepted: 05/21/2019] [Indexed: 12/17/2022]
Abstract
Obesity, type two diabetes mellitus and insulin resistance are associated with increased oxidative stress and inflammation. Unfermented green rooibos is an aspalathin rich variant of traditional fermented rooibos (Aspalathus linearis) and has a high polyphenol content. The present study aimed to determine the histologically observable effects of a commercially produced, aspalathin-rich green rooibos extract, Afriplex GRT™ (GRE) in a diet-induced obese rat model. Male Wistar rats (N = 28) were randomly assigned to four study groups (n = 7): control (C), green rooibos (GRT), high-fat diet (HFD) and experimental (HFD-GRT) group. Body mass was determined prior to euthanasia and liver mass was determined after death. The left lateral lobe of the liver was processed to wax and stained using haematoxylin and eosin (H & E), Masson's trichrome stain, Gordons and Sweet's reticulin impregnation and periodic acid-Schiff stain. Frozen liver tissue sections were used for Oil red O staining. Morphometric quantification of steatosis, semiquantitative pathology grading and scoring were performed and verified by a veterinary histopathologist. A significant increase in body and liver mass was observed in the HFD groups while co-treatment with green rooibos significantly reduced both. The volume and area of steatosis were significantly increased in the HFD groups while the area of steatosis significantly reduced with green rooibos co-treatment. The percentage, location and type of steatosis as well as presence of inflammation and hepatocellular injury were reduced in the HFD group co-treated with GRE. These findings suggest that a GRE has potential as an anti-steatotic, anti-inflammatory and weight reducing agent in vivo.
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Affiliation(s)
- J I Layman
- Division of Clinical Anatomy, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - D L Pereira
- Division of Clinical Anatomy, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa
| | - N Chellan
- Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg, South Africa
| | - B Huisamen
- Division of Medical Physiology, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa; Biomedical Research and Innovation Platform, South African Medical Research Council, Tygerberg, South Africa
| | - S H Kotzé
- Division of Clinical Anatomy, Department of Biomedical Sciences, Faculty of Medicine and Health Sciences, Stellenbosch University, South Africa.
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Pyrzanowska J, Fecka I, Mirowska-Guzel D, Joniec-Maciejak I, Blecharz-Klin K, Piechal A, Wojnar E, Widy-Tyszkiewicz E. Long-term administration of Aspalathus linearis infusion affects spatial memory of adult Sprague-Dawley male rats as well as increases their striatal dopamine content. JOURNAL OF ETHNOPHARMACOLOGY 2019; 238:111881. [PMID: 31002838 DOI: 10.1016/j.jep.2019.111881] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/30/2018] [Revised: 03/20/2019] [Accepted: 04/11/2019] [Indexed: 06/09/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE Everyday use of the herbal tea rooibos, produced from Aspalathus linearis (Brum.f) Dahlg. (Fabaceae) is customary in South Africa, a continuation of its historical use by indigenous people. Although evidence of its traditional indications is anecdotal, rooibos tea is regarded as a general health tea. AIMS OF THE STUDY Available contemporary research indicates to broad cell protective activity of rooibos focusing on its antioxidative, anti-inflammatory, anti-hyperglycaemic and antithrombotic features affecting metabolic syndrome, cardiovascular risk and neuroprotection. Nevertheless little is known about its impact on brain functions. The present experiment aimed to evaluate the possible behavioural and neurochemical effects of long-term oral administration of "fermented"" rooibos herbal tea (FRHT) infusions to adult male Sprague-Dawley rats. MATERIALS AND METHODS Infusions, prepared using 1, 2 and 4 g of "fermented"" (oxidised) A. linearis leaves for 100 ml of hot water, were characterised in terms of flavonoid content by ultra-high and high performance liquid chromatography (UHPLC-qTOF-MS, HPLC-DAD) and administered to rats as sole drinking fluid for 12 weeks. Spatial memory behaviour was assessed in a modified version of the Morris water maze. Dopamine, noradrenaline, serotonin and their metabolite levels (DOPAC, 3-MT, HVA, MHPG, 5-HIAA) were quantified in prefrontal cortex, hippocampus and striatum by HPLC-ECD. Body weight and blood glucose level were additionally estimated. RESULTS All FRHT-treated rats showed improvement of long-term spatial memory defined as increased number of crossings over the previous platform position in SE quadrant of the water maze. It was not accompanied by excessive motor activity. Striatal dopamine and its metabolite 3-MT (3-methoxytyramine) levels were increased in treated rats. There were no differences in body weight gain between control and treated animals but blood glucose level was significantly lower in the latter ones. CONCLUSION The improvement of long-term memory in FRHT-treated rats and stimulating impact of FRHT on their dopaminergic striatal transmission support the wellness enhancing effect of rooibos tea, contributing to a better understanding of the neurological background of traditional habitual consumption of this herbal tea.
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Affiliation(s)
- Justyna Pyrzanowska
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Banacha 1b, 02-097, Warsaw, Poland.
| | - Izabela Fecka
- Department of Pharmacognosy and Herbal Medicines, Wroclaw Medical University, Borowska 211, 50-556, Wroclaw, Poland.
| | - Dagmara Mirowska-Guzel
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Banacha 1b, 02-097, Warsaw, Poland.
| | - Ilona Joniec-Maciejak
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Banacha 1b, 02-097, Warsaw, Poland.
| | - Kamilla Blecharz-Klin
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Banacha 1b, 02-097, Warsaw, Poland.
| | - Agnieszka Piechal
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Banacha 1b, 02-097, Warsaw, Poland.
| | - Ewa Wojnar
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Banacha 1b, 02-097, Warsaw, Poland.
| | - Ewa Widy-Tyszkiewicz
- Department of Experimental and Clinical Pharmacology, Medical University of Warsaw, Centre for Preclinical Research and Technology CePT, Banacha 1b, 02-097, Warsaw, Poland.
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Visualization of Aspalathin in Rooibos ( Aspalathus linearis) Plant and Herbal Tea Extracts Using Thin-Layer Chromatography. Molecules 2019; 24:molecules24050938. [PMID: 30866512 PMCID: PMC6429207 DOI: 10.3390/molecules24050938] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2018] [Revised: 01/14/2019] [Accepted: 01/18/2019] [Indexed: 01/01/2023] Open
Abstract
Aspalathin, the main polyphenol of rooibos (Aspalathus linearis), is associated with diverse health promoting properties of the tea. During fermentation, aspalathin is oxidized and concentrations are significantly reduced. Standardized methods for quality control of rooibos products do not investigate aspalathin, since current techniques of aspalathin detection require expensive equipment and expertise. Here, we describe a simple and fast thin-layer chromatography (TLC) method that can reproducibly visualize aspalathin in rooibos herbal tea and plant extracts at a limit of detection (LOD) equal to 178.7 ng and a limit of quantification (LOQ) equal to 541.6 ng. Aspalathin is a rare compound, so far only found in A. linearis and its (rare) sister species A. pendula. Therefore, aspalathin could serve as a marker compound for authentication and quality control of rooibos products, and the described TLC method represents a cost-effective approach for high-throughput screening of plant and herbal tea extracts.
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Smith C, Swart A. Aspalathus linearis (Rooibos) - a functional food targeting cardiovascular disease. Food Funct 2019; 9:5041-5058. [PMID: 30183052 DOI: 10.1039/c8fo01010b] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Increasing consumer bias toward natural products and the considerable wealth of indigenous knowledge has precipitated an upturn in market-driven research into potentially beneficial medicinal plants. In this context, Aspalathus linearis (Rooibos) has been identified to be a promising candidate which may impact cardiovascular disease (CVD), which is one of the most widely studied chronic diseases of modern times. Despite these efforts, ischemic heart disease remains the number one cause of mortality globally. Apart from genetic predisposition and other aetiological mechanisms specific to particular types of CVD, co-factors from interlinked systems contribute significantly to disease development and the severity of its clinical manifestation. The bioactivity of Rooibos is directed towards multiple therapeutic targets. Experimental data to date include antioxidant, anti-inflammatory and anti-diabetic effects, as well as modulatory effects in terms of the immune system, adrenal steroidogenesis and lipid metabolism. This review integrates relevant literature on the therapeutic potential of Rooibos in the context of CVD, which is currently the most common of non-communicable diseases. The therapeutic value of whole plant extracts versus isolated active ingredients are addressed, together with the potential for overdose or herb-drug interaction. The body of research undertaken to date clearly underlines the benefits of Rooibos as both preventative and complementary therapeutic functional food in the context of CVD.
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Affiliation(s)
- Carine Smith
- Dept Physiological Sciences, Science Faculty, Stellenbosch University, Stellenbosch, South Africa.
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The Potential of South African Herbal Tisanes, Rooibos and Honeybush in the Management of Type 2 Diabetes Mellitus. Molecules 2018; 23:molecules23123207. [PMID: 30563087 PMCID: PMC6321617 DOI: 10.3390/molecules23123207] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2018] [Revised: 11/21/2018] [Accepted: 11/30/2018] [Indexed: 12/15/2022] Open
Abstract
Diabetes mellitus is a metabolic disease that can lead to high morbidity, mortality and long-term complications. Available treatment strategies, which are mainly based on treating hyperglycemia, with insulin and other pharmacological agents are not completely efficient and can even lead to development of unwanted side effects. Scientific evidence suggests that bioactive compounds from teas and other plant-based foods, which are known source of natural antioxidants, could be an attractive strategy to preferentially treat and manage type 2 diabetes mellitus (T2DM) and thus, have significant therapeutic implications. In this review, we attempt an in-depth analysis and discussion of the current progress in our understanding of the antidiabetic potential of two commercialized South Africa herbal tisanes—Rooibos and Honeybush and their polyphenols.
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Sasaki M, Nishida N, Shimada M. A Beneficial Role of Rooibos in Diabetes Mellitus: A Systematic Review and Meta-Analysis. Molecules 2018; 23:molecules23040839. [PMID: 29642387 PMCID: PMC6017582 DOI: 10.3390/molecules23040839] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2018] [Revised: 03/28/2018] [Accepted: 04/05/2018] [Indexed: 12/20/2022] Open
Abstract
In a rapid increase in cases of diabetes mellitus worldwide, there has been interested in the use of plant-derived polyphenols as nutraceuticals to prevent the onset and progression of diabetes mellitus and its associated complications. Aspalathus linearis, commonly known as rooibos, is a rich source of uncommon glycosylated plant polyphenols with various critical health-promoting properties, including the prevention and treatment of diabetes mellitus (DM). This study aimed to examine these effects by meta-analyzing the current evidence in diabetic rodent models. Peer-reviewed studies written in English from two databases, PubMed and Embase, were searched up to 28 February 2018. Studies reporting blood glucose levels in diabetic rodents with and without receiving rooibos extracts or their major phenolic compounds are included. Twelve studies enrolling 88 diabetic rodents treated with rooibos extracts or their polyphenols and 85 diabetic control males reported blood glucose levels. The pooled effect size was -0.89 (95% CI: -1.44 to -0.35) with a substantial heterogeneity (I² = 67.0%). This effect was likely to be modified by type of rooibos extracts and their polyphenols and treatment period. Blood glucose levels were significantly lower in diabetic rodent models treated with the phenolic compound rich in rooibos extracts, PPAG.
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Affiliation(s)
- Moe Sasaki
- Graduate School of Nutritional Science, Sagami Women's University, 2-1-1 Bunkyo, Minami-ku, Sagamihara, Kanagawa 252-0383, Japan.
| | - Nami Nishida
- Faculty of Nutritional Science, Sagami Women's University, 2-1-1 Bunkyo, Minami-ku, Sagamihara, Kanagawa 252-0383, Japan.
| | - Masako Shimada
- Graduate School of Nutritional Science, Sagami Women's University, 2-1-1 Bunkyo, Minami-ku, Sagamihara, Kanagawa 252-0383, Japan.
- Faculty of Nutritional Science, Sagami Women's University, 2-1-1 Bunkyo, Minami-ku, Sagamihara, Kanagawa 252-0383, Japan.
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Song I, Roels S, Martens GA, Bouwens L. Circulating microRNA-375 as biomarker of pancreatic beta cell death and protection of beta cell mass by cytoprotective compounds. PLoS One 2017; 12:e0186480. [PMID: 29040320 PMCID: PMC5645134 DOI: 10.1371/journal.pone.0186480] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2017] [Accepted: 10/02/2017] [Indexed: 12/31/2022] Open
Abstract
Objective Previous studies demonstrated that circulating microRNA-375 (miR-375) is a suitable plasma biomarker for real-time detection of beta cell death. The present study evaluated the use of this biomarker to assess the beta cytoprotective effect of phenylpropenoic acid glucoside (PPAG), which was previously demonstrated to protect beta cells against various types of injury, and of exendin-4, which is an established antidiabetic drug. Methods PPAG or exendin-4 were administered in mice treated with streptozotocin (STZ) to acutely induce beta cell death. Beta cell mass and apoptotic death were measured in pancreatic tissue sections. Circulating miR-375 was measured in blood plasma by RT-qPCR. The release of miR-375 was also measured in vitro by MIN-6 beta cells. Results Administration of STZ resulted in measurable circulating levels of miR-375, a decrease in beta cell mass and increase in frequency of apoptotic beta cells. In vitro, there was a good correlation between miR-375 release and the extent of beta cell death. Treatment of mice with PPAG or exendin-4 significantly attenuated STZ-induced loss of beta cell mass and beta cell apoptosis, and normalized the blood level of miR-375. Conclusions These findings show the potential use of serological miR-375 measurements to evaluate the beta cytoprotective effect of (potential) antidiabetic drugs in vivo.
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Affiliation(s)
- Imane Song
- Cell Differentiation Lab, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Sarah Roels
- Diabetes Research Center, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Geert A. Martens
- Diabetes Research Center, Vrije Universiteit Brussel (VUB), Brussels, Belgium
| | - Luc Bouwens
- Cell Differentiation Lab, Vrije Universiteit Brussel (VUB), Brussels, Belgium
- * E-mail:
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Dludla PV, Joubert E, Muller CJF, Louw J, Johnson R. Hyperglycemia-induced oxidative stress and heart disease-cardioprotective effects of rooibos flavonoids and phenylpyruvic acid-2- O-β-D-glucoside. Nutr Metab (Lond) 2017; 14:45. [PMID: 28702068 PMCID: PMC5504778 DOI: 10.1186/s12986-017-0200-8] [Citation(s) in RCA: 65] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2017] [Accepted: 06/23/2017] [Indexed: 12/15/2022] Open
Abstract
Diabetic patients are at an increased risk of developing heart failure when compared to their non-diabetic counter parts. Accumulative evidence suggests chronic hyperglycemia to be central in the development of myocardial infarction in these patients. At present, there are limited therapies aimed at specifically protecting the diabetic heart at risk from hyperglycemia-induced injury. Oxidative stress, through over production of free radical species, has been hypothesized to alter mitochondrial function and abnormally augment the activity of the NADPH oxidase enzyme system resulting in accelerated myocardial injury within a diabetic state. This has led to a dramatic increase in the exploration of plant-derived materials known to possess antioxidative properties. Several edible plants contain various natural constituents, including polyphenols that may counteract oxidative-induced tissue damage through their modulatory effects of intracellular signaling pathways. Rooibos, an indigenous South African plant, well-known for its use as herbal tea, is increasingly studied for its metabolic benefits. Prospective studies linking diet rich in polyphenols from rooibos to reduced diabetes associated cardiovascular complications have not been extensively assessed. Aspalathin, a flavonoid, and phenylpyruvic acid-2-O-β-D-glucoside, a phenolic precursor, are some of the major compounds found in rooibos that can ameliorate hyperglycemia-induced cardiomyocyte damage in vitro. While the latter has demonstrated potential to protect against cell apoptosis, the proposed mechanism of action of aspalathin is linked to its capacity to enhance the expression of nuclear factor (erythroid-derived 2)-like 2 (Nrf2) expression, an intracellular antioxidant response element. Thus, here we review literature on the potential cardioprotective properties of flavonoids and a phenylpropenoic acid found in rooibos against diabetes-induced oxidative injury.
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Affiliation(s)
- Phiwayinkosi V Dludla
- Biomedical Research and Innovation Platform (BRIP), South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505 South Africa.,Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg, South Africa
| | - Elizabeth Joubert
- Plant Bioactives Group, Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC) Infruitec- Nietvoorbij, Stellenbosch, South Africa.,Department of Food Science, Stellenbosch University, Stellenbosch, South Africa
| | - Christo J F Muller
- Biomedical Research and Innovation Platform (BRIP), South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505 South Africa.,Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg, South Africa.,Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa, South Africa
| | - Johan Louw
- Biomedical Research and Innovation Platform (BRIP), South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505 South Africa.,Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa, South Africa
| | - Rabia Johnson
- Biomedical Research and Innovation Platform (BRIP), South African Medical Research Council, P.O. Box 19070, Tygerberg, 7505 South Africa.,Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg, South Africa
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14
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Muller CJF, Malherbe CJ, Chellan N, Yagasaki K, Miura Y, Joubert E. Potential of rooibos, its major C-glucosyl flavonoids, and Z-2-(β-D-glucopyranosyloxy)-3-phenylpropenoic acid in prevention of metabolic syndrome. Crit Rev Food Sci Nutr 2017; 58:227-246. [PMID: 27305453 DOI: 10.1080/10408398.2016.1157568] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
Risk factors of type 2 diabetes mellitus (T2D) and cardiovascular disease (CVD) cluster together and are termed the metabolic syndrome. Key factors driving the metabolic syndrome are inflammation, oxidative stress, insulin resistance (IR), and obesity. IR is defined as the impairment of insulin to achieve its physiological effects, resulting in glucose and lipid metabolic dysfunction in tissues such as muscle, fat, kidney, liver, and pancreatic β-cells. The potential of rooibos extract and its major C-glucosyl flavonoids, in particular aspalathin, a C-glucoside dihydrochalcone, as well as the phenolic precursor, Z-2-(β-D-glucopyranosyloxy)-3-phenylpropenoic acid, to prevent the metabolic syndrome, will be highlighted. The mechanisms whereby these phenolic compounds elicit positive effects on inflammation, cellular oxidative stress and transcription factors that regulate the expression of genes involved in glucose and lipid metabolism will be discussed in terms of their potential in ameliorating features of the metabolic syndrome and the development of serious metabolic disease. An overview of the phenolic composition of rooibos and the changes during processing will provide relevant background on this herbal tea, while a discussion of the bioavailability of the major rooibos C-glucosyl flavonoids will give insight into a key aspect of the bioefficacy of rooibos.
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Affiliation(s)
- Christo J F Muller
- a Biomedical Research and Innovation Platform , South African Medical Research Council , Tygerberg , South Africa
| | - Christiaan J Malherbe
- b Post-Harvest and Wine Technology Division , Agricultural Research Council (ARC), Infruitec-Nietvoorbij , Stellenbosch , South Africa
| | - Nireshni Chellan
- a Biomedical Research and Innovation Platform , South African Medical Research Council , Tygerberg , South Africa
| | - Kazumi Yagasaki
- c Division of Applied Biological Chemistry , Institute of Agriculture, Tokyo University of Agriculture and Technology , Fuchu , Tokyo , Japan.,d Center for Bioscience Research and Education , Utsunomiya University , Utsunomiya , Tochigi , Japan
| | - Yutaka Miura
- c Division of Applied Biological Chemistry , Institute of Agriculture, Tokyo University of Agriculture and Technology , Fuchu , Tokyo , Japan
| | - Elizabeth Joubert
- b Post-Harvest and Wine Technology Division , Agricultural Research Council (ARC), Infruitec-Nietvoorbij , Stellenbosch , South Africa.,e Department of Food Science , Stellenbosch University, Private Bag X1, Matieland Stellenbosch , South Africa
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15
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Dludla PV, Muller CJF, Joubert E, Louw J, Essop MF, Gabuza KB, Ghoor S, Huisamen B, Johnson R. Aspalathin Protects the Heart against Hyperglycemia-Induced Oxidative Damage by Up-Regulating Nrf2 Expression. Molecules 2017; 22:molecules22010129. [PMID: 28098811 PMCID: PMC6155802 DOI: 10.3390/molecules22010129] [Citation(s) in RCA: 54] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 12/26/2016] [Accepted: 01/05/2017] [Indexed: 01/14/2023] Open
Abstract
Aspalathin (ASP) can protect H9c2 cardiomyocytes against high glucose (HG)-induced shifts in myocardial substrate preference, oxidative stress, and apoptosis. The protective mechanism of ASP remains unknown. However, as one of possible, it is well known that phytochemical flavonoids reduce oxidative stress via nuclear factor (erythroid-derived 2)-like 2 (Nrf2) activation resulting in up-regulation of antioxidant genes and enzymes. Therefore, we hypothesized that ASP protects the myocardium against HG- and hyperglycemia-induced oxidative damage by up-regulating Nrf2 expression in H9c2 cardiomyocytes and diabetic (db/db) mice, respectively. Using an oxidative stress RT2 Profiler PCR array, ASP at a dose of 1 µM was demonstrated to protect H9c2 cardiomyocytes against HG-induced oxidative stress, but silencing of Nrf2 abolished this protective response of ASP and exacerbated cardiomyocyte apoptosis. Db/db mice and their non-diabetic (db/+) littermate controls were subsequently treated daily for six weeks with either a low (13 mg/kg) or high (130 mg/kg) ASP dose. Compared to nondiabetic mice the db/db mice presented increased cardiac remodeling and enlarged left ventricular wall that occurred concomitant to enhanced oxidative stress. Daily treatment of mice with ASP at a dose of 130 mg/kg for six weeks was more effective at reversing complications than both a low dose ASP or metformin, eliciting enhanced expression of Nrf2 and its downstream antioxidant genes. These results indicate that ASP maintains cellular homeostasis and protects the myocardium against hyperglycemia-induced oxidative stress through activation of Nrf2 and its downstream target genes.
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MESH Headings
- Animals
- Apoptosis/drug effects
- Cardiotonic Agents/pharmacology
- Cell Line
- Chalcones/pharmacology
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/pathology
- Drug Administration Schedule
- Gene Expression Regulation
- Glucose/antagonists & inhibitors
- Glucose/toxicity
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Transgenic
- Myocardium/metabolism
- Myocardium/pathology
- Myocytes, Cardiac/cytology
- Myocytes, Cardiac/drug effects
- Myocytes, Cardiac/metabolism
- NF-E2-Related Factor 2/agonists
- NF-E2-Related Factor 2/antagonists & inhibitors
- NF-E2-Related Factor 2/genetics
- NF-E2-Related Factor 2/metabolism
- RNA, Small Interfering/genetics
- RNA, Small Interfering/metabolism
- Rats
- Signal Transduction
- Ventricular Remodeling/drug effects
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Affiliation(s)
- Phiwayinkosi V Dludla
- Biomedical Research and Innovation Platform (BRIP), Medical Research Council (MRC), Tygerberg 7505, South Africa.
- Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg 7505, South Africa.
| | - Christo J F Muller
- Biomedical Research and Innovation Platform (BRIP), Medical Research Council (MRC), Tygerberg 7505, South Africa.
- Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg 7505, South Africa.
- Department of Biochemistry and Microbiology, University of Zululand, Kwadlangezwa 3886, South Africa.
| | - Elizabeth Joubert
- Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Stellenbosch 7599, South Africa.
- Department of Food Science, Stellenbosch University, Stellenbosch 7599, South Africa.
| | - Johan Louw
- Biomedical Research and Innovation Platform (BRIP), Medical Research Council (MRC), Tygerberg 7505, South Africa.
- Department of Biochemistry and Microbiology, University of Zululand, Kwadlangezwa 3886, South Africa.
| | - M Faadiel Essop
- Cardio-Metabolic Research Group (CMRG), Department of Physiological Sciences, Stellenbosch University, Stellenbosch 7599, South Africa.
| | - Kwazi B Gabuza
- Biomedical Research and Innovation Platform (BRIP), Medical Research Council (MRC), Tygerberg 7505, South Africa.
| | - Samira Ghoor
- Biomedical Research and Innovation Platform (BRIP), Medical Research Council (MRC), Tygerberg 7505, South Africa.
| | - Barbara Huisamen
- Biomedical Research and Innovation Platform (BRIP), Medical Research Council (MRC), Tygerberg 7505, South Africa.
- Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg 7505, South Africa.
| | - Rabia Johnson
- Biomedical Research and Innovation Platform (BRIP), Medical Research Council (MRC), Tygerberg 7505, South Africa.
- Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg 7505, South Africa.
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16
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Smith C, Swart AC. Rooibos ( Aspalathus linearis ) facilitates an anti-inflammatory state, modulating IL-6 and IL-10 while not inhibiting the acute glucocorticoid response to a mild novel stressor in vivo. J Funct Foods 2016. [DOI: 10.1016/j.jff.2016.08.055] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
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17
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Patel O, Muller C, Joubert E, Louw J, Rosenkranz B, Awortwe C. Inhibitory Interactions of Aspalathus linearis (Rooibos) Extracts and Compounds, Aspalathin and Z-2-(β-d-Glucopyranosyloxy)-3-phenylpropenoic Acid, on Cytochromes Metabolizing Hypoglycemic and Hypolipidemic Drugs. Molecules 2016; 21:molecules21111515. [PMID: 27845750 PMCID: PMC6273468 DOI: 10.3390/molecules21111515] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2016] [Revised: 10/21/2016] [Accepted: 10/29/2016] [Indexed: 12/12/2022] Open
Abstract
Rooibos extract, due to its glucose and lipid lowering effects, has potential as a nutraceutical for improvement of metabolic dysfunction. Potential herb-drug interactions as a result of the use of natural products are of increasing concern. Cytochrome P450 enzymes, CYP2C8, CYP2C9, and CYP3A4, are important in the metabolism of hypoglycemic drugs, such as thiazolidinediones (TZDs) and sulfonylureas, and hypocholesterolemic drugs, such as atorvastatin. This study investigated the effects of rooibos extracts, prepared from "unfermented" and "fermented" rooibos plant material and two of the major bioactive compounds, Z-2-(β-d-glucopyranosyloxy)-3-phenylpropenoic acid (PPAG) and aspalathin (ASP), on Vivid® recombinant CYP450 enzymes. Unfermented (GRT) and fermented (FRE) rooibos extracts inhibited the activity of CYP2C8 (7.69 ± 8.85 µg/mL and 8.93 ± 8.88 µg/mL, respectively) and CYP3A4 (31.33 ± 4.69 µg/mL and 51.44 ± 4.31 µg/mL, respectively) based on their respective IC50 concentrations. Both extracts dose- and time-dependently inhibited CYP2C8 activity, but only time-dependently inhibited CYP2C9. CYP3A4 showed concentration-dependent inhibition by ASP, GRT, and FRE at 25, 50, and 100 µg/mL concentrations. ASP, GRT, and FRE time-dependently inhibited CYP3A4 activity with GRT and FRE showing a more potent time-dependent inhibition, comparable to erythromycin. These findings suggest that herb-drug interactions may occur when nutraceuticals containing rooibos extracts are co-administered with hypoglycemic drugs such as TZDs, sulfonylureas, and dyslipidemic drug, atorvastatin.
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Affiliation(s)
- Oelfah Patel
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg 7505, South Africa.
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, University of Stellenbosch, P.O. Box 241, Cape Town 8000, South Africa.
| | - Christo Muller
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg 7505, South Africa.
| | - Elizabeth Joubert
- Post-Harvest and Wine Technology Division, Agricultural Research Council, Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa.
- Department of Food Science, Stellenbosch University, Private Bag X1, Matieland 7602, South Africa.
| | - Johan Louw
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg 7505, South Africa.
| | - Bernd Rosenkranz
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, University of Stellenbosch, P.O. Box 241, Cape Town 8000, South Africa.
| | - Charles Awortwe
- Biomedical Research and Innovation Platform, South African Medical Research Council, P.O. Box 19070, Tygerberg 7505, South Africa.
- Division of Clinical Pharmacology, Department of Medicine, Faculty of Medicine and Health Sciences, University of Stellenbosch, P.O. Box 241, Cape Town 8000, South Africa.
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18
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Phenylpropenoic Acid Glucoside from Rooibos Protects Pancreatic Beta Cells against Cell Death Induced by Acute Injury. PLoS One 2016; 11:e0157604. [PMID: 27299564 PMCID: PMC4907458 DOI: 10.1371/journal.pone.0157604] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2016] [Accepted: 06/01/2016] [Indexed: 11/28/2022] Open
Abstract
Objective Previous studies demonstrated that a phenylpropenoic acid glucoside (PPAG) from rooibos (Aspalathus linearis) extract had anti-hyperglycemic activity and significant protective effects on the pancreatic beta cell mass in a chronic diet-induced diabetes model. The present study evaluated the cytoprotective effect of the phytochemical on beta cells exposed to acute cell stress. Methods Synthetically prepared PPAG was administered orally in mice treated with a single dose of streptozotocin to acutely induce beta cell death and hyperglycemia. Its effect was assessed on beta cell mass, proliferation and apoptotic cell death. Its cytoprotective effect was also studied in vitro on INS-1E beta cells and on human pancreatic islet cells. Results Treatment with the phytochemical PPAG protected beta cells during the first days after the insult against apoptotic cell death, as evidenced by TUNEL staining, and prevented loss of expression of anti-apoptotic protein BCL2 in vivo. In vitro, PPAG protected INS-1E beta cells from streptozotocin-induced apoptosis and necrosis in a BCL2-dependent and independent way, respectively, depending on glucose concentration. PPAG also protected human pancreatic islet cells against the cytotoxic action of the fatty acid palmitate. Conclusions These findings show the potential use of PPAG as phytomedicine which protects the beta cell mass exposed to acute diabetogenic stress.
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19
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Kamakura R, Son MJ, de Beer D, Joubert E, Miura Y, Yagasaki K. Antidiabetic effect of green rooibos (Aspalathus linearis) extract in cultured cells and type 2 diabetic model KK-A(y) mice. Cytotechnology 2014; 67:699-710. [PMID: 25410530 DOI: 10.1007/s10616-014-9816-y] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2014] [Accepted: 11/07/2014] [Indexed: 02/06/2023] Open
Abstract
Previous studies have demonstrated antidiabetic effects for rooibos (Aspalathus linearis) and aspalathin (ASP), one of its main polyphenols. Rooibos, an endemic plant of South Africa, is well-known for its use as herbal tea. Green ('unfermented') rooibos has been shown to contain more ASP than 'fermented' rooibos tea, currently the major product. In the present study, we investigated the antidiabetic effect of green rooibos extract (GRE) through studies on glucose uptake in L6 myotubes and on pancreatic β-cell protective ability from reactive oxygen species (ROS) in RIN-5F cells. Its in vivo effect was also examined using obese diabetic KK-A(y) mice. GRE increased glucose uptake under insulin absent condition and induced phosphorylation of 5'-adenosine monophosphate-activated protein kinase (AMPK) in L6 myotubes as previously demonstrated for ASP. In addition to AMPK, GRE also promoted phosphorylation of Akt, another promoter of glucose transporter 4 (GLUT4) translocation, in L6 myotubes unlike ASP, suggesting an involvement of GRE component(s) other than ASP in Akt phosphorylation. Promotion of GLUT4 translocation to the plasma membrane by GRE in L6 myotubes was demonstrated by Western blotting analysis. GRE suppressed the advanced glycation end products (AGEs)-induced increase in ROS levels in RIN-5F pancreatic β-cells. Subchronic feeding with GRE suppressed the increase in fasting blood glucose levels in type 2 diabetic model KK-A(y) mice. These in vitro and in vivo results strongly suggest that GRE has antidiabetic potential through multiple modes of action.
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Affiliation(s)
- Remi Kamakura
- Department of Applied Biological Chemistry, Graduate School of Agriculture, Tokyo University of Agriculture and Technology, Fuchu, Tokyo, 183-8509, Japan
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20
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Gannon NP, Conn CA, Vaughan RA. Dietary stimulators of GLUT4 expression and translocation in skeletal muscle: a mini-review. Mol Nutr Food Res 2014; 59:48-64. [PMID: 25215442 DOI: 10.1002/mnfr.201400414] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 09/07/2014] [Accepted: 09/08/2014] [Indexed: 12/23/2022]
Abstract
Chronic insulin resistance can lead to type II diabetes mellitus, which is also directly influenced by an individual's genetics as well as their lifestyle. Under normal circumstances, insulin facilitates glucose uptake in skeletal muscle and adipose tissue by stimulating glucose transporter 4 (GLUT4) translocation and activity. GLUT4 activity is directly correlated with the ability to clear elevated blood glucose and insulin sensitivity. In diabetes, energy excess and prolonged hyperinsulinemia suppress muscle and adipose response to insulin, in part through reduced GLUT4 membrane levels. This work uniquely describes much of the experimental data demonstrating the effects of various dietary components on GLUT4 expression and translocation in skeletal muscle. These observations implicate several individual dietary chemicals as potential adjuvant therapies in the maintenance of diabetes and insulin resistance.
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Affiliation(s)
- Nicholas P Gannon
- Department of Biochemistry and Molecular Biology, University of New Mexico, Health Sciences Center, School of Medicine, Albuquerque, NM, USA
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21
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Mathijs I, Da Cunha DA, Himpe E, Ladriere L, Chellan N, Roux CR, Joubert E, Muller C, Cnop M, Louw J, Bouwens L. Phenylpropenoic acid glucoside augments pancreatic beta cell mass in high-fat diet-fed mice and protects beta cells from ER stress-induced apoptosis. Mol Nutr Food Res 2014; 58:1980-90. [PMID: 25044754 DOI: 10.1002/mnfr.201400211] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2014] [Revised: 06/27/2014] [Accepted: 07/01/2014] [Indexed: 12/24/2022]
Abstract
SCOPE A major goal of diabetes therapy is to identify novel drugs that preserve or expand pancreatic beta cell mass. Here, we examined the effect of a phenylpropenoic acid glucoside (PPAG) on the beta cell mass, and via which mechanism this effect is established. METHODS AND RESULTS Mice were fed a high-fat and fructose-containing diet to induce obesity and hyperglycemia. PPAG treatment protected obese mice from diet-induced hyperglycemia and resulted in a tripling of beta cell mass. The effect of the phytochemical on beta cell mass was neither due to increased proliferation, as determined by Ki67 immunostaining, nor to neogenesis, which was assessed by genetic lineage tracing. TUNEL staining revealed suppressed apoptosis in PPAG-treated obese mice. In vitro, PPAG protected beta cells from palmitate-induced apoptosis. It protected beta cells against ER stress by increasing expression of antiapoptotic B-cell lymphoma 2 (BCL2) protein without affecting proapoptotic signals. CONCLUSIONS We identified an antidiabetic phytochemical that protects pancreatic beta cells from ER stress and apoptosis induced by high-fat diet/lipotoxicity. At the tissue level, this led to a tripling of beta cell mass. At the molecular level, the protective effect of the phytochemical was mediated by increasing BCL2 expression in beta cells.
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Affiliation(s)
- Iris Mathijs
- Cell Differentiation Lab, Vrije Universiteit Brussel, Brussels, Belgium
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22
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Dludla PV, Muller CJF, Louw J, Joubert E, Salie R, Opoku AR, Johnson R. The cardioprotective effect of an aqueous extract of fermented rooibos (Aspalathus linearis) on cultured cardiomyocytes derived from diabetic rats. PHYTOMEDICINE : INTERNATIONAL JOURNAL OF PHYTOTHERAPY AND PHYTOPHARMACOLOGY 2014; 21:595-601. [PMID: 24268738 DOI: 10.1016/j.phymed.2013.10.029] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/02/2013] [Revised: 09/26/2013] [Accepted: 10/27/2013] [Indexed: 06/02/2023]
Abstract
Diabetic cardiomyopathy (DCM) is a disorder of the heart muscle that contributes to cardiovascular deaths in the diabetic population. Excessive generation of free radicals has been directly implicated in the pathogenesis of DCM. The use of antioxidants, through dietary supplementation, to combat increased cellular oxidative stress has gained popularity worldwide. Aspalathus linearis (rooibos) is a popular herbal tea that contains a novel antioxidant, aspalathin. Literature has reported on the antidiabetic, anti-inflammatory and free radical scavenging effects of rooibos. However, its protective effect against DCM has not been established. Therefore, this study investigated whether chronic exposure to an aqueous extract of fermented rooibos (FRE) has an ex vivo cardioprotective effect on hearts obtained from streptozotocin (STZ) induced diabetic rats. Adult Wistar rats were injected with 40 mg/kg of STZ. Two weeks after STZ injection, cardiomyocytes were isolated and cultured. Cultured cardiomyocytes were treated with FRE (1 and 10 μg/ml), vitamin E (50 μg/ml), and n-acetyl cysteine (1mM) for 6h, before exposure to either hydrogen peroxide (H2O2) or an ischemic solution. Cardiomyocytes exposed to H2O2 or an ischemic solution showed a decrease in metabolic activity and glutathione content with a concomitant increase in apoptosis and intracellular reactive oxygen species. Pretreatment with FRE was able to combat these effects and the observed amelioration was better than the known antioxidant vitamin E. This study provides evidence that an aqueous extract of fermented rooibos protects cardiomyocytes, derived from diabetic rats, against experimentally induced oxidative stress and ischemia.
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Affiliation(s)
- P V Dludla
- Diabetes Discovery Platform, South African Medical Research Council, Tygerberg 7505, South Africa; Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa
| | - C J F Muller
- Diabetes Discovery Platform, South African Medical Research Council, Tygerberg 7505, South Africa
| | - J Louw
- Diabetes Discovery Platform, South African Medical Research Council, Tygerberg 7505, South Africa
| | - E Joubert
- Post-Harvest and Wine Technology Division, Agricultural Research Council (ARC) Infruitec-Nietvoorbij, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Stellenbosch 7602, South Africa
| | - R Salie
- Diabetes Discovery Platform, South African Medical Research Council, Tygerberg 7505, South Africa; Division of Medical Physiology, Faculty of Health Sciences, Stellenbosch University, Tygerberg 7505, South Africa
| | - A R Opoku
- Department of Biochemistry and Microbiology, University of Zululand, KwaDlangezwa 3886, South Africa
| | - R Johnson
- Diabetes Discovery Platform, South African Medical Research Council, Tygerberg 7505, South Africa.
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