Phenolic compounds, antioxidant and antileishmanial activities of kombucha as affected by fermentation time

Study the impact of fermentation time on the phytochemical properties, antioxidant and antileishmanial activities.

The preparation of Kombucha tea by fermentation was performed under aseptic conditions and symbiotic culture of bacteria and yeast (SCOBY) layer was maintained in culture for continuous growth in a water-sugar (4 L-500 g) mixture for 7, 14, 21, 28 and 35 days. The process of preparation was performed using a decoction. Phenolic compounds, flavonoids, and tannins was determined using standard method. The antioxidant activity was determined using three tests: DPPH•, ABTS• + and FRAP methods. Finally, the antileishmanial activity was performed in vitro on Leishmania donovani promastigote strains.

The qualitative analysis of the constituents showed the kombucha drink was rich in saponins, terpenoids, quinones, phenolic compounds, catechins and coumarins depending on the fermentation times. Depending on the fermentation time (7 days, 14 days, 21 days, 28 days and 35 days), significant quantities of phenolic compounds were obtained in the tea with values ranging from 182.42 to 509.41 mg GAE/g dry extract; 15.83-53.05 mg QE/g dry extract and 6.16-51.82 mg TAE/g dry extract respectively for phenolic compounds, total flavonoids and total tannins. The SC₅₀ values of DPPH• and ABTS• ⁺, were 14.57 μg/mL; and 21.47 μg/mL after 14 and 21 days of fermentation respectively indicating a good antioxidant profile. The inhibition of the promastigote form of Leishmania donovani responsible for visceral leishmaniasis was observed with the samples obtained after 7 days, 14 days and 28 days with inhibitory concentrations 50 of: 131.2, 48.86 and 128.8 μg/mL respectively. The antileishmanial activity was more pronounced with the Kombucha tea after 14 days (KBT14) extract (48.86 μg/mL).

The Kombucha tea revealed the presence of phenolic compounds at different fermentation time. In addition, a good antioxidant profile was observed with the different radicals analyzed. Also, the inhibition of the Leishmania parasite was obtained. Therefore, the Kombucha tea constitutes a source bioactive molecules with antioxidant properties against Leishmania parasite.