Green tea and kombucha characterization: Phenolic composition, antioxidant capacity and enzymatic inhibition potential

Kombucha as a Solvent for Chitosan Coatings: A New Strategy to Extend Shelf Life of Red Peppers

Plastic pollution and environmental degradation necessitate the development of natural, biodegradable food preservation materials. This study examined chitosan-based film-forming solutions using kombucha derived from black tea, lemon balm, and chamomile as natural solvents rich in bioactive compounds. Lemon balm kombucha solutions were used to create chitosan films and coat red peppers. The study assessed the mechanical properties of the films and the effects of chitosan coating on peppers, including texture, ascorbic acid content, sensory attributes, and antioxidant activity. Microbiological tests showed that a chitosan-lemon balm kombucha solution acted against Escherichia coli, Pseudomonas aeruginosa and Salmonella enterica. Lemon balm kombucha had high total phenolic (381.67 µg GAeq/mL) and flavonoid (21.05 µg Qeq/mL) contents. The chitosan film exhibited a tensile strength of 11.08 MPa and an elongation at break of 53.45%. The water vapor transmission rate of the obtained chitosan film was 131.84 g/m2·24 h. Coated peppers showed a 32% increase in skin strength and retained 11% more ascorbic acid after 15 days. Sensory evaluation revealed no significant differences from controls. These results highlight lemon balm kombucha as a promising natural solvent for chitosan coatings, which have the potential to extend red pepper shelf life and to support food preservation.

Exploiting agri-food residues for kombucha tea and bacterial cellulose production

Bio-valorization of agri-food wastes lies in their possible conversion into fermented foodstuffs/beverages and/or biodegradable polymers such as bacterial cellulose. In this study, three different kombucha cultures were formulated using agri-food waste materials, citrus fruit residues and used coffee grounds, as alternative carbon and nitrogen sources, respectively. Over 21 days of fermentation, the kinetic profile was followed by monitoring cell density, pH variation, minerals, trace elements and production of bacterial cellulose. Moreover, the total phenolic and radical scavenging capacity was measured by spectrophotometric tests on the beverage and bacterial cellulose. Several classes of compounds were detected by gas chromatography coupled with mass spectrometry performing extractions on the headspace above fresh kombucha beverages and their lyophilized fractions, using solid phase micro extraction and liquid phase extraction, respectively. The obtained results allowed assessing molecular profiles of each kombucha beverages. A chemometric meta-analysis of the data revealed the individual impacts of the single ingredients and the effects of the fermentation process.

Supramolecular deep eutectic solvents as green media for efficient extraction of tea polyphenols and its application in bio-active film

Ultrasonic-assisted supramolecular deep eutectic solvents (SUPRADESs) extraction of active ingredients from plants is a novel green extraction method. In this study, a series of SUPRADESs combined with cyclodextrins (CDs) and organic acids or polyols were synthesized and used to extract the tea polyphenols (TP). SUPRADESs, consisting of Hydroxypropyl-β-cyclodextrin (HP-β-CD) and L-lactic acid (LA) with a mass ratio of 1:5, contributed to achieving the maximum extraction efficiency of TP. Then, the extraction rate was optimized by different experimental conditions, and the optimal extraction yield of TP was (111.36 ± 2.31 mg/g). Then, the biofilms were successfully prepared using HP-β-CD/LA extract as a plasticizer for polyvinyl alcohol and chitosan. Furthermore, the antioxidant activity of extract and film containing TP was determined using biochemical kits. Finally, the synthesis process of HP-β-CD/LA and the TP extraction were investigated using molecular simulation. The findings indicate that enhanced TP yield could be attributed to an increase in non-covalent bonds between HP-β-CD and TP through the assistance of LA.

Tea Polyphenol-Derived Carbon Dots Alleviate Abdominal Aortic Aneurysm Progression by Mitigating Oxidative Stress and Ferroptosis

Abdominal aortic aneurysm (AAA) is a cardiovascular disease with potentially fatal consequences, yet effective therapies to prevent its progression remain unavailable. Oxidative stress is associated with AAA development. Carbon dots have reactive oxygen species-scavenging activity, while green tea extract exhibits robust antioxidant properties. However, the potential of green tea derived carbon dots in mitigating AAA progression has not been fully elucidated. In this study, tea polyphenol carbon dots (TP-CDs) were synthesized via hydrothermal methods and characterized for their antioxidant properties. The antioxidant effects of TP-CDs were evaluated, and TP-CDs' impact on phenotypic transformation, oxidative stress, apoptosis and ferroptosis was investigated comprehensively in an Ang II-induced AAA model, employing techniques such as Western blotting, flow cytometry, and immunohistochemistry. The results revealed that TP-CDs effectively alleviated oxidative stress induced by Ang II stimulation, thereby inhibiting phenotypic transformation, apoptosis, and ferroptosis in vivo. Furthermore, treatment with TP-CDs significantly attenuated AAA progression in a mouse AAA model. Overall, these findings demonstrate that TP-CDs reduced reactive oxygen species levels in the microenvironment and alleviated the progression of AAA, offering a promising therapeutic strategy for this condition.

Metagenomic analysis and bioactive profiling of kombucha fermentation: antioxidant, antibacterial activities, and molecular docking insights into gastric cancer therapeutics

Kombucha is fermented and produced with a biofilm called a symbiotic culture of bacteria and yeast, which is drunk all over the world for its beneficial effects on human health and energy levels. The metagenomic study of kombucha frequently detected microorganisms in proteobacteria, firmicutes, and actinobacteria. And also, yeast and fungi are Ascomycota and Basidiomycota is present in green leaf and sugarcane juice fermented kombucha. The kombucha extracts' biological activities were assessed using pH, total phenolic content, antioxidant, antibacterial, and anticancer activity. Fermentation may enhance biological activity and the generation of bioactive substances. These results showed the pH -3.1 ± 0.2 and TPC -0.721 μg/mL of gallic acid equivalent. The antioxidant radicals scavenging activity of kombucha was evaluated by DPPH, ABTS, H2O2 and TAC. The bioactive chemicals identified by FT-IR and HR-LC/MS analysis of Kombucha totaled 45 components. The identified compounds were further move on to perform molecular docking study against gastric cancer target proteins 4H9M, 2DQ7 and 1TVO are binding with Nequinate compounds showing best LibDock scores 105.12, 114.49, and 108.97. So, this study suggests that knowledge can potentially active bioactive compounds are present in kombucha and it's stimulated the mechanism of gastrointestinal transit. Additionally, the metagenomic analysis gives strength to understand the bacterial and fungal distribution and its molecular mechanism from Kombucha.

Kombucha enables to inhibit digestive enzymes activity and adipocyte differentiation of OP9 cells

Obesity is a global challenging epidemic caused by surplus adipose accumulation or energy intake, and available medications are quite limited. Studies focused on identifying potent anti-adipogenic pharmaceuticals and functional foods have gained great interests. This study evaluated the obesity prevention potential of oolong tea kombucha (OTK) and yellow tea kombucha (YTK) by in vitro experiments. The results showed that the total polyphenol content in OTK and YTK increased by 50.00% and 47.49% after fermentation, and the antioxidative capacity of kombucha was enhanced by 7.57% and 7.83% as well. After fermentation, the inhibitory activity of OTK and YTK on α-amylase and lipase was increased by 53.15% and 64.43%, and 45.24% and 39.74%, respectively. The anti-adipogenic effects evaluated by using mouse OP9 cell model indicated that both OTK and YTK could downregulate the expression levels of FABP4, PPARγ, C/EBPα, and SERBP-1C which are involved with adipocyte differentiation. Taken together, kombucha showed great potential in regulating glucose and lipid metabolism by inhibiting digestive enzymes and adipocyte differentiation, which could be a functional beverage in aiding obesity prevention or treatments. However, further animal or clinical experiments are needed to verify its potential in obesity intervention. PRACTICAL APPLICATION: This study showed that kombucha showed great potential in preventing obesity, which provided an alternative functional beverage for obesity intervening or prevention.

Comparative study of the anti-inflammatory activity of etoricoxib and Matcha green tea against acute kidney injury induced by gamma radiation in rats

PURPOSE

The primary objective of this study was to conduct a comparative analysis of the anti-inflammatory activity between Etoricoxib (ETO) and Matcha green tea (MG) in the context of acute kidney injury (AKI) induced by ionizing gamma radiation (IR) in female rats. Furthermore, the potential impact of whole body IR exposure on the intestinal system and serum estradiol levels was investigated. Additionally, it was acknowledged that the ETO and MG treatments might have exerted favorable effects on the intestinal and hormonal responses.

MATERIALS AND METHODS

Six groups of rats were assigned to different treatments: control, ETO, MG, irradiation (IRR), ETO + IRR, and MG + IRR. The evaluation included measuring the total phenolic and flavonoid contents of ETO and MG, as well as assessing their antioxidant activity, radical scavenging capacity, reducing power, and total antioxidant capacity. Kidney function was assessed through serum creatinine and urea levels. Oxidative stress markers, including superoxide dismutase, glutathione, malondialdehyde, and catalase, were measured to evaluate the antioxidant effects of ETO and MG. The anti-inflammatory potential of the treatments was evaluated by measuring STAT-3 and interleukins (IL-6, IL-23, and IL-17) using an ELISA assay. Prostaglandin E2 receptor (PGE-2) mRNA expression, histopathological examination, and immunohistochemistry for NF-κB inhibitors were performed to investigate the underlying mechanisms in kidney tissue homogenates. Histopathological changes and DNA fragmentation in the intestinal tissues were determined, and the characterization of Matcha green tea was performed using liquid chromatography-mass spectrometry (LC-MS). This allowed for the identification and quantification of various compounds present in Matcha green tea. Furthermore, the study assessed the effect of IR and treatments on estrogen levels in female rats.

RESULTS

Data showed that both ETO and MG had the potential to mitigate the adverse effects of AKI induced by IR. Notably, MG exhibited greater efficacy in attenuating oxidative stress and inflammation associated with renal injury. These findings revealed and compared the effects of ETO and MG in alleviating AKI caused by IR. MG demonstrated greater anti-inflammatory and antioxidant properties, highlighting its potential as a natural therapeutic agent.

CONCLUSIONS

These results contribute to the growing evidence supporting the use of MG in managing IR-induced renal complications. Future studies should focus on elucidating the molecular mechanisms and optimizing the application of MG in clinical settings.

Probing the binding mechanism of tea polyphenols from different processing methods to anti-obesity and TMAO production-related enzymes through in silico molecular docking

Tea polyphenols possess anti-obesity properties and reduce TMAO levels. However, the variability of tea polyphenols under different processing methods and their preventive efficacy requires further exploration. This study systematically evaluated the antioxidant, hypoglycemic, and hypolipotropic enzyme capacities of GT, YT and DT through UPLC-ESI-MS/MS analysis of catechin profiles. OPLS, correlation analysis, and molecular docking were employed to investigate the compounds and inhibitory mechanisms targeting hypoglycemic, hypolipidemic, and TMAO-producing enzymes. GT exhibited significantly lower IC50 values for biological activity and higher catechins contents compared to YT and DT (p < 0.05). Strong positive correlations were observed between EGCG, CG, and ECG and biological activities (r ≥ 7.4, p < 0.001). Molecular docking results highlighted the establishment of stable hydrogen bonds and hydrophobic interactions between EGCG, CG, ECG, and the receptor. These findings contribute novel insights into the mechanisms by which tea polyphenols prevent obesity and inhibit TMAO production.

Kombucha as a Potential Active Ingredient in Cosmetics-An Ex Vivo Skin Permeation Study

Kombucha is a non-alcoholic beverage, that is increasingly used in the cosmetic industry. The available literature reports the positive effects of kombucha on the skin, in particular its antioxidant action. However, there is a lack of information on skin permeation and the accumulation of active ingredients showing such effects. Skin aging is largely dependent on oxidative stress, therefore in our study we assessed the ex vivo permeation of two types of kombucha (green and black tea) through porcine skin. The antioxidant activity (DPPH, ABTS, FRAP methods) and total polyphenol content of these extracts were determined before and after permeation testing. Moreover, the content of selected phenolic acids as well as caffeine was assessed. Skin permeation was determined using a Franz diffusion cell. The antioxidant activity of both Kombuchas was found to be high. In addition, gallic acid, chlorogenic acid, protocatechuic acid, coumaric acid, m-hydroxybenzoic acid, and caffeine were identified. A 24-h ex vivo study showed the permeation of some phenolic acids and caffeine and their accumulation in the skin. Our results confirm the importance of studying the skin permeation of what are still little known ingredients in cosmetic preparations. Evaluation of the accumulation of these ingredients can guarantee the efficacy of such preparations.

Dried tea residue can alter the blood metabolism and the composition and functionality of the intestinal microbiota in Hu sheep

Ruminant animals face multiple challenges during the rearing process, including immune disorders and oxidative stress. Green tea by-products have gained widespread attention for their significant immunomodulatory and antioxidant effects, leading to their application in livestock production. In this study, we investigated the effects of Dried Tea Residue (DTR) as a feed additive on the growth performance, blood biochemical indicators, and hindgut microbial structure and function of Hu sheep. Sixteen Hu sheep were randomly divided into two groups and fed with 0 and 100 g/d of DTR, respectively. Data were recorded over a 56-day feeding period. Compared to the control group, there were no significant changes in the production performance of Hu sheep fed with DTR. However, the sheep fed with DTR showed a significant increase in IgA (p < 0.001), IgG (p = 0.005), IgM (p = 0.003), T-SOD (p = 0.013), GSH-Px (p = 0.005), and CAT (p < 0.001) in the blood, along with a significant decrease in albumin (p = 0.019), high density lipoprotein (p = 0.050), and triglyceride (p = 0.021). DTR supplementation enhanced the fiber digestion ability of hindgut microbiota, optimized the microbial community structure, and increased the abundance of carbohydrate-digesting enzymes. Therefore, DTR can be used as a natural feed additive in ruminant animal production to enhance their immune and antioxidant capabilities, thereby improving the health status of ruminant animals.

Kombucha: Challenges for Health and Mental Health

BACKGROUND

Increasing research into probiotics is showing potential benefits for health in general and mental health in particular. Kombucha is a recent beverage and can be considered a probiotic drink, but little is known about its effects on physical and mental health. This product is experiencing growth in the market; however, there are no scientific results to support its potential for physical and mental health.

AIM

This review article aims to draw attention to this issue and to highlight the lack of studies in this area.

KEY FINDINGS AND CONCLUSIONS

The lack of legislation for the correct marketing of this product may also constrain clinical studies. However, clinical studies are of utmost importance for an in-depth understanding of the effects of this product on the human body. More research is needed, not only to better understand the impact of Kombucha on the human body, but also to ensure the application of regulatory guidelines for its production and marketing and enable its safe and effective consumption.

Oxidative stress and inflammation in diabetic nephropathy: role of polyphenols

Diabetic nephropathy (DN) often leads to end-stage renal disease. Oxidative stress demonstrates a crucial act in the onset and progression of DN, which triggers various pathological processes while promoting the activation of inflammation and forming a vicious oxidative stress-inflammation cycle that induces podocyte injury, extracellular matrix accumulation, glomerulosclerosis, epithelial-mesenchymal transition, renal tubular atrophy, and proteinuria. Conventional treatments for DN have limited efficacy. Polyphenols, as antioxidants, are widely used in DN with multiple targets and fewer adverse effects. This review reveals the oxidative stress and oxidative stress-associated inflammation in DN that led to pathological damage to renal cells, including podocytes, endothelial cells, mesangial cells, and renal tubular epithelial cells. It demonstrates the potent antioxidant and anti-inflammatory properties by targeting Nrf2, SIRT1, HMGB1, NF-κB, and NLRP3 of polyphenols, including quercetin, resveratrol, curcumin, and phenolic acid. However, there remains a long way to a comprehensive understanding of molecular mechanisms and applications for the clinical therapy of polyphenols.

Chemical and Aromatic Changes during Fermentation of Kombucha Beverages Produced Using Strawberry Tree (Arbutus unedo) Fruits

The use of alternative ingredients in the production of kombucha has seen a recent increase. Our research aimed to characterize the chemical, nutritional, microbial, and aromatic profiles of kombucha beverages prepared with strawberry tree (Arbutus unedo) fruits fermented with three different SCOBYs for 21 days. The analyses showed similar levels of microbiological groups (aerobic mesophilic microorganisms, lactic acid bacteria, acetic acid bacteria, and yeasts)among the SCOBYs used. The beverages studied displayed a decrease in pH value and carbohydrate content, and protein degradation was also observed as fermentation progressed. However, the increase in total phenolic compounds during the first week proved to be a point of interest. A total of 20 volatile organic compounds were detected, giving different sensory qualities to the beverages: higher ethanol, benzaldehyde-4-ethyl, or acetic acid depending on the SCOBY used. The results obtained indicated that strawberry tree kombucha might be an alternative beverage with notable nutritional and aromatic properties, with fermentation time and SCOBY composition being identified as crucial factors.