Comparison of phytochemical composition, antimicrobial, antifungal, and antioxidant activities of lipophilic and ethanolic green tea leaf extracts

Abstract

Infection diseases are a worldwide important problem for medicine and pharmacy. Today, there is a high interest in the evolution of new antimicrobial drugs due to the increasing percentage of resistant bacteria and fungi strains. Green tea leaf contains a variety of natural compounds that are possible to apply in the creation of new antimicrobial drugs. The aim of the work was to compare phytochemical composition, antimicrobial, antifungal activities of lipophilic and ethanolic green tea leaf extracts. Materials and methods. The object of the research was the lipophilic extract obtained using chloroform, along with two ethanolic extracts of green tea leaves. One of the ethanolic extracts had been previously processed with chloroform, while the other had not. Antioxidant activity was determined by the potentiometric method, while antimicrobial and antifungal activities were assessed by the “wells” method. Results. The lipophilic extract of green tea leaves contains predominantly caffeine and organic acids, with the lowest amount of phenolic compounds. In contrast, the ethanolic extracts show the opposite pattern, with phenolic compounds predominating and caffeine present in lower quantities. The lipophilic extract exhibits greater inhibition of the growth of S. aureus, E. coli, P. vulgaris, B. subtilis, and C. albicans compared to the 96 % ethanolic extract processed with chloroform, with inhibition rates of 19 %, 18 %, 12 %, 12 %, 16 %, and 20 % respectively. When comparing antimicrobial activity to the 96 % ethanolic extract without chloroform treatment, the results remained consistent. The antioxidant activity of the lipophilic extract was 58.7 and 60.0 times lower than that of the 96 % ethanolic extract processed with chloroform and the 96 % ethanolic extract without treatment, respectively. Conclusions. The study revealed that the lipophilic extract exhibited greater inhibition of the growth of both Gram-positive and Gram-negative bacteria as well as fungi compared to the ethanolic extracts. However, it showed a lower level of antioxidant activity. It is hypothesized that caffeine, organic acids, and catechins may interact synergistically to enhance the antimicrobial and antifungal activity of green tea leaf extracts. The lipophilic extract shows promise for further development in the production of antimicrobial and antifungal drugs.

Keywords

• green tea
• lipophilic extract
• caffeine
• organic acids
• pharmacologic action