Green Tea Extract Increases Soluble RAGE and Improves Renal Function in Patients with Diabetic Nephropathy

Potential mechanism of tea for treating osteoporosis, osteoarthritis, and rheumatoid arthritis

Osteoporosis (OP), osteoarthritis (OA), and rheumatoid arthritis (RA) are common bone and joint diseases with a high incidence and long duration. Thus, these conditions can affect the lives of middle-aged and elderly people. Tea drinking is a traditional lifestyle in China, and the long-term intake of tea and its active ingredients is beneficial to human health. However, the mechanisms of action of tea and its active ingredients against OP, OA, and RA are not completely elucidated. This study aimed to assess the therapeutic role and related mechanisms of tea and its active ingredients in OP, OA, and RA. Moreover, it expanded the potential mechanisms of tea efficacy based on network pharmacology and molecular docking. Results showed that tea has potential anti-COX properties and hormone-like effects. Compared with a single component, different tea components synergize or antagonize each other, thereby resulting in a more evident dual effect. In conclusion, tea has great potential in the medical and healthcare fields. Nevertheless, further research on the composition, proportion, and synergistic mechanism of several tea components should be performed.

Effect of tea intake on genetic predisposition to gout and uric acid: a Mendelian randomization study

Objective

The effect of tea on gout and uric acid is still controversial. This study aims to analyze the effect of tea intake on genetic predisposition to gout, idiopathic gout, gout due to impairment of renal function as well as uric acid by Mendelian randomization (MR).

Methods

Forty independent single nucleotide polymorphisms (SNPs) associated with tea intake were selected from UK Biobank. SNPs for uric acid were obtained from BioBank Japan, SNPs for gout were obtained from UK Biobank, and SNPs for gout due to impairment of renal function and idiopathic gout were derived from FinnGen. The causal relationship of exposure-outcome was tested using inverse variance weighted, MR-Egger and weighted median. MR-Egger intercept was employed to assess horizontal pleiotropy, Cochran's Q test was used to assess heterogeneity, and leave-one-out sensitivity analysis was utilized to analyze the stability of the results.

Results

The results of MR analysis showed that tea intake was negatively associated with gout due to impairment of renal function (OR 0.997, 95% CI 0.994 to 0.999, P = 0.017), whereas there was no causal association with gout, idiopathic gout, and uric acid (P > 0.05), for which sensitivity analysis suggested that these results were robust.

Conclusions

There was a genetic predisposition effect of increased tea intake on the reduced risk of gout due to impairment of renal function, whereas there was no such effect on gout, idiopathic gout, and uric acid. Tea intake may become an important option in the dietary treatment of gout due to impairment of renal function.

Piperine as a Potential Nutraceutical Agent for Managing Diabetes and Its Complications: A Literature Review

The global prevalence of diabetes and its related complications has increased drastically and is currently a worldwide health challenge. There is still an urgent need for safe and effective natural products and supplements as alternative and/or adjunctive therapeutic interventions. Nowadays, people pay more and more attention to the nutritional and medicinal value of food ingredients. As one of the most widely employed spices in cooking, pepper also has novel medicinal values attributed to its main component, piperine (Pip). Pip is an amide alkaloid with pleiotropic properties such as anti-inflammatory, antioxidant, anti-cancer, and other related activities. Recently, Pip has received increasing scientific attention due to its antidiabetic and related complication properties. However, the values of existing studies are limited due to being scattered and unsystematic. The present study reviewed the therapeutic potential and possible mechanisms of Pip in diabetes and related complications, with the aim of providing promising candidates for the development of novel and effective alternative and/or adjunctive nutraceutical agents for the management of diabetes.

Effects of green tea polyphenol extract and epigallocatechin-3-O-gallate on diabetes mellitus and diabetic complications: Recent advances

Diabetes mellitus is one of the major non-communicable diseases accounting for millions of death annually and increasing economic burden. Hyperglycemic condition in diabetes creates oxidative stress that plays a pivotal role in developing diabetes complications affecting multiple organs such as the heart, liver, kidney, retina, and brain. Green tea from the plant Camellia sinensis is a common beverage popular in many countries for its health benefits. Green tea extract (GTE) is rich in many biologically active compounds, e.g., epigallocatechin-3-O-gallate (EGCG), which acts as a potent antioxidant. Recently, several lines of evidence have shown the promising results of GTE and EGCG for diabetes management. Here, we have critically reviewed the effects of GTE and EGCC on diabetes in animal models and clinical studies. The concerns and challenges regarding the clinical use of GTE and EGCG against diabetes are also briefly discussed. Numerous beneficial effects of green tea and its catechins, particularly EGCG, make this natural product an attractive pharmacological agent that can be further developed to treat diabetes and its complications.

L-theanine protects rat kidney from D-galactose-induced injury via inhibition of the AGEs/RAGE signaling pathway

As the irreversible products of the non-enzymatic reduction of sugars and the amino groups of proteins or peptides, advanced glycation end products (AGEs) are metabolized and excreted via the kidneys. However, if AGEs are not metabolized, they are deposited in the kidneys and bind to AGE receptors (RAGE), which can induce various pathological changes, including oxidative stress, apoptosis, and inflammation. This study used the D-galactose (DG)-induced rat model to explore the potential role and mechanism of L-theanine in inhibiting AGEs/RAGE-related signaling pathways in renal tissues. L-theanine increased the activities of glutathione peroxidase (GSH-Px) and total antioxidant capacity (T-AOC) while downregulating the contents of malondialdehyde (MDA) and AGEs in renal tissues induced by DG (P < 0.05). By inhibiting the upregulation of RAGE protein expression attributed to AGEs accumulation (P < 0.05), L-theanine downregulated phosphorylated nuclear factor (p-NF-κB (p65)), Bax, and cleaved-caspase-3 expression and increased Bcl-2 protein expression (P < 0.05), thereby alleviating the oxidative stress damage and reducing the inflammation and cell injury induced by DG. In addition, the Congo red staining section of renal tissue also showed that the natural product L-theanine can protect against AGEs-induced renal damage in DG-induced rat model.