Kombucha is a fermented tea beverage prepared as a result of the symbiotic nature of bacterial cultures and yeast, the so-called SCOBY (Symbiotic Cultures of Bacteria and Yeasts). Kombucha is characterised by rich chemical content and healthy properties. It includes organic acids, minerals and vitamins originating mainly from tea, amino acids, and biologically active compounds—polyphenols in particular. Kombucha is prepared mainly in the form of black tea, but other tea types are increasingly often used as well, which can significantly impact its content and health benefits. This work shows that the type of tea has a significant influence on the parameters associated with the antioxidant potential, pH, as well as the content of acetic acid, alcohol or sugar. Red tea and green tea on the 1st and 14th day of fermentation are a particularly prominent source of antioxidants, especially polyphenols, including flavonoids. Therefore, the choice of other tea types than the traditionally used black tea and the subjection of these tea types to fermentation seems to be beneficial in terms of the healthy properties of kombucha.

Japanese matcha is a type of powdered green tea, grown in a traditional way. Shading of the plants during the growth period enhances the processes of synthesis and accumulation of biologically active compounds, including theanine, caffeine, chlorophyll and various types of catechins. Green tea contains four main catechins, i.e., (−)-epicatechin (EC), (−)-epicatechin-3-gallate (ECG), (−)-epigallocatechin (EGC) and (−)-epigallocatechin-3-gallate (EGCG), of which the latter is the most active and abundant and matcha is their best condensed source. Due to its unique chemical composition and prized flavour, which sets it apart from other tea beverages, it is considered the highest quality tea. Its health-promoting properties are attributed to the high content of antioxidant and anti-inflammatory substances. Studies confirming the high antioxidant potential of tea beverages claim that it originates from the considerable content of catechins, a type of phenolic compound with beneficial effects on human health. Due to its potential for preventing many diseases and supporting cognitive function, regular consumption of matcha may have a positive effect on both physical and mental health. The aim of this review was to compile the health benefits of matcha tea. It is the first such review to be undertaken, and presents its main bioactive compounds in a systematic manner.

Matcha green tea (Camellia sinensis), which originates from Japan, is commonly considered as particularly beneficial to health. A large content of polyphenols, amino acids (mainly tannins) and caffeine potentially increase the antioxidant properties of the drink. The aim of the study was to determine the antioxidant potential and the content of substances with an antioxidant effect—vitamin C, total polyphenol content including flavonoids—in infusions made from Traditional Matcha (from the first and second harvests) and Daily Matcha (from the second and third harvests) at different temperatures. The infusions were made by pouring 100 mL of distilled water once at various temperatures (25 °C, 70 °C, 80 °C and 90 °C) over 1.75 g of the plant material. Matcha tea is characterized by a high level of antioxidant substances (flavonoids 1968.8 mg/L; polyphenols 1765.1 mg/L; vitamin C 44.8 mg/L) as well as antioxidant potential (41.2% DPPH (10× dilution); 6129.5 µM Fe(II)/dm³ FRAP). The concentration of these compounds depends on the time at which the plant material was harvested as well as on the temperature of water used to prepare the infusions. For most parameters, the highest values were observed in infusions prepared at 90 °C and from the daily Matcha.

Background: Stress is a natural response of the body, induced by factors of a physical (hunger, thirst, and infection) and/or psychological (perceived threat, anxiety, or concern) nature. Chronic, long-term stress may cause problems with sleep, concentration, and memory, as well as affective disorders. The passionflower (Passiflora incarnata) is a perennial plant with documented therapeutic properties. The literature data suggest that the passionflower itself, as well as its preparations, helps reduce stress and can therefore be helpful in the treatment of insomnia, anxiety, and depression. The objective of this systematic review was to evaluate Passiflora incarnata in terms of its neuropsychiatric effects. Methods: The scientific databases PubMed, ClinTrials.gov, and Embase were searched up to 22 October 2019. The search identified randomized clinical trials describing the effects of Passiflora incarnata in neuropsychiatric disorders. Results: The systematic review included nine clinical trials. The duration of the studies included in the analysis varied widely, from one day up to 30 days. Study participants were no less than 18 years old. In each of the papers, the effects of passionflower were measured by using a number of different tests and scales. The majority of studies reported reduced anxiety levels following the administration of Passiflora incarnata preparations, with the effect less evident in people with mild anxiety symptoms. No adverse effects, including memory loss or collapse of psychometric functions, were observed. Conclusion: Passiflora incarnata may be helpful in treating some symptoms in neuropsychiatric patients.

Non-alcoholic fatty liver disease (NAFLD) is regarded as one of the most common liver pathologies in many societies. Resveratrol, as a phenolic compound with powerful antioxidant and anti-inflammatory properties exerting positive effects on the lipid profile and lipid accumulation and also on insulin resistance, appears to be an effective, natural, and safe complementary treatment option in NAFLD therapy. This meta-analysis was undertaken to evaluate the effects of resveratrol supplementation in NAFLD patients. To this end, scientific databases PubMed/Medline/Embase were searched up to 19 March 2020. We included seven randomized clinical trials (RCTs) with a total of 302 patients with NAFLD. In all the trials included in the analysis, resveratrol was administered daily over periods between 56 and 180 days in doses ranging from 500 mg to 3000 mg a day. The results of this meta-analysis reveal that resveratrol supplementation, irrespective of the dose or duration, did not affect the analyzed parameters (p < 0.05). The sole exception was an increase in alanine aminotransferase following the administration of resveratrol (p = 0.041). Currently available evidence is insufficient to confirm the efficacy of resveratrol in the management of NAFLD. Due to the inconsistencies between the existing scientific reports, a number of which found a positive effect on NAFLD-related parameters; further research in this area is needed.

Kombucha dates back thousands of years and is reported to have originated in East Asia. It is produced by fermenting tea with added sugar using SCOBY (symbiotic culture of bacteria and yeast). Its health benefits can be attributed to the metabolites produced during the fermentation process. Valuable ingredients of this fermented tea beverage include acetic acid, glucuronic acid, vitamins, enzymes, sugars and polyphenols. Tea, and consequently kombucha, contains numerous minerals, and one of them is fluoride. Under physiological conditions, fluoride plays a significant role in hard tissue mineralisation processes. However, even at low concentrations with long-term exposure, fluorides may accumulate in the body and cause a range of detrimental effects. Kombucha is traditionally brewed with black tea, but these days it is becoming increasingly popular to use other types of tea to make it, which may significantly affect its composition and health-promoting effects. The aim of the study was to evaluate the fluoride content in kombucha beverages derived from black, green, white and red tea. Fluoride content was measured at different time points during fermentation. The potentiometric method was used to determine the content of fluoride ions. It was demonstrated that kombucha is a major dietary source of fluoride (0.42–0.93 mg/L) and that the type of tea used has a significant effect on its chemical composition. Therefore, it recommended to make the beverage with white or red tea, due to the lowest fluoride content and ensure food safety.Graphical Abstract