Aspalathin-Rich Green Rooibos Extract Lowers LDL-Cholesterol and Oxidative Status in High-Fat Diet-Induced Diabetic Vervet Monkeys

Abstract

Type 2 diabetic patients possess a two to four-fold-increased risk for cardiovascular diseases (CVD). Hyperglycemia, oxidative stress associated with endothelial dysfunction and dyslipidemia are regarded as pro-atherogenic mechanisms of CVD. In this study, high-fat diet-induced diabetic and non-diabetic vervet monkeys were treated with 90 mg/kg of aspalathin-rich green rooibos extract (Afriplex GRT) for 28 days, followed by a 1-month wash-out period. Supplementation showed improvements in both the intravenous glucose tolerance test (IVGTT) glycemic area under curve (AUC) and total cholesterol (due to a decrease of the low-density lipoprotein [LDL]) values in diabetics, while non-diabetic monkeys benefited from an increase in high-density lipoprotein (HDL) levels. No variation of plasma coenzyme Q10 (CoQ10) were found, suggesting that the LDL-lowering effect of Afriplex GRT could be related to its ability to modulate the mevalonate pathway differently from statins. Concerning the plasma oxidative status, a decrease in percentage of oxidized CoQ10 and circulating oxidized LDL (ox-LDL) levels after supplementation was observed in diabetics. Finally, the direct correlation between the amount of oxidized LDL and total LDL concentration, and the inverse correlation between ox-LDL and plasma CoQ10 levels, detected in the diabetic monkeys highlighted the potential cardiovascular protective role of green rooibos extract. Taken together, these findings suggest that Afriplex GRT could counteract hyperglycemia, oxidative stress and dyslipidemia, thereby lowering fundamental cardiovascular risk factors associated with diabetes.

Coenzyme Q10 Supplementation Improves Adipokine Levels and Alleviates Inflammation and Lipid Peroxidation in Conditions of Metabolic Syndrome: A Meta-Analysis of Randomized Controlled Trials

“…Thus, broadly indicating that by effectively regulating adipokine levels, CoQ 10 can greatly impact metabolic health in connection to ameliorating inflammation and oxidative stress in patients with T2D, NAFLD, or hypertension, as increasingly discussed [28][29][30]53]. Therapeutic benefits of CoQ 10 supplementation are essential important since its deficiency in the body or enhanced oxidation status has been linked with compromised metabolic function [24,54,55]. In fact, Gholami and colleagues [36] demonstrated that at the end of the intervention, CoQ 10 supplementation significantly improved its serum levels, including that of adiponectin while reducing that of MDA in patients with T2D.…”

“…), according to a modified Downs and Black's guideline, as previously mentioned. The overall median score range of the included studies was 22 (19)(20)(21)(22)(23)(24), with five of them rated excellent (21-24 scores) and one rated as good (19 scores). In addition, KM used the Cohen's Kappa interrater to assess the degree of agreement in terms of quality assessment scores of the included studies [33].…”

“…Notably, its deficiency is associated with the generation of oxidative stress and myocardial damage in the diabetic state [22]. Whereas, dietary intake of CoQ 10 is directly linked with enhanced levels of ubiquinol-10 within the human body, which is further crucial for blocking lipid peroxidation by protecting against low-density lipoprotein oxidation in conditions on metabolic syndrome [23,24]. Beyond its impact on lipid peroxidation, published evidence from randomized clinical trials (RCTs) shows that CoQ 10 remains important in ameliorating inflammation and improving adipokine function in conditions of metabolic syndrome [25][26][27].…”

Therapeutic effects of an aspalathin-rich green rooibos extract, pioglitazone and atorvastatin combination therapy in diabetic db/db mice

“…Within this context, several studies have alluded to the glucose and lipid modulating effects of Aspalathus linearis (rooibos) [26][27][28][29], a plant better known for its use as an herbal tea. The Aspalathus genus uniquely contains a C-glucosyl dihydrochalcone, aspalathin [29], which was demonstrated to stimulate glucose uptake in muscle tissues and increases insulin release in pancreatic beta cells, thus benefiting glucose homeostasis in various models of T2D [30]. In addition, rooibos has also been shown to have LDL-C lowering [31,32], and cardioprotective effects [33][34][35][36].…”

Shelf-Life Stability of Ready-to-Use Green Rooibos Iced Tea Powder—Assessment of Physical, Chemical, and Sensory Properties

“…A functional ingredient that gained interest in recent years due to its potential to modulate the metabolic syndrome is aspalathin-rich green rooibos extract (GRE) [ 6 ], shown to improve hyperglycaemia and HDL/LDL blood cholesterol profiles in non-human primates [ 7 ]. Aspalathin delivery in a RTD green rooibos iced tea presents a challenge as its stability is poor in solution, as shown by De Beer et al [ 8 ].…”