Abstract:
Due to its naturally occurring medicinal ingredients known as polyphenols, tea attracts the interest
of the pharmaceutical and scientific disciplines. Besides the established antioxidant activity, many
phenolic compounds in tea exhibit significant antimicrobial activity. Environmental factors and
crop management substantially influence the amount and activity of polyphenols available in tea
leaves. In Sri Lanka, there are six main agro-ecological regions where tea is grown using either
conventional or organic management. Present study focused to determine the effects of tea production
system and their growing region on polyphenol content and antimicrobial properties of made tea.
Fresh leaf samples were collected from randomly selected tea estates each for organically certified and
conventional from major tea growing regions in Sri Lanka. They were manufactured into CTC
black tea using a miniature system. Polyphenol content was assessed by ISO standard method, while
the anti-bacterial and anti-fungal properties were evaluated using disk diffusion technique against
Escherichia coli ATCC 25922 and clinical pathogen of Aspergillus niger. Polyphenol content, anti-
bacterial and anti-fungal properties were significantly different (P<0.05) between the tea production
systems and among the growing regions, where organic tea had higher polyphenol content, anti-
bacterial and anti-fungal properties than conventional teas. The Southern region tea had greater
anti-bacterial and anti-fungal properties probably due to the high polyphenol content, while it was
the lowest in Uva region. In conclusion, this research presents preliminary evidence that Sri Lankan
teas grown and managed organically have superior antimicrobial properties over conventional teas.
To confirm the findings, more investigation using time series measurement in all tea-growing regions
is suggested.
