Kombuchas from green and black teas have different phenolic profile, which impacts their antioxidant capacities, antibacterial and antiproliferative activities

UPLC-QTOF-MSE phenolic profile of kombuchas produced from the fermentation of green tea or black tea at 25 degrees C for 10 days was investigated along with the determination of their antioxidant capacities, antibacterial and antiproliferative activities. Overall, 127 phenolic compounds (70.2% flavonoids, 18.3% phenolic acids, 8.4% other polyphenols, 2.3% lignans and 0.8% stilbenes) were identified, with 103 phenolic compounds reported for the first time in kombuchas. A greater diversity and abundance of phenolic compounds was detected in black tea kombucha, which resulted in a higher antioxidant capacity. However, the green tea kombucha was the only one that presented antibacterial activity against all the bacteria tested and an increased antiproliferative activity against the cancer cell lines, which was attributed to the presence of catechins among the most abundant phenolic compounds and verbascoside as an exclusive compound. Thus, the type of tea used in the kombucha production interferes in its bioactive composition and properties.