Antioxidative and antimicrobial activities of black tea

Wong, Siew Ching (2007) Antioxidative and antimicrobial activities of black tea. Universiti Malaysia Sabah. (Unpublished)


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Chemistry and biological activities of black tea are not well defined, thus, it should be investigated to better understand their properties and efficiencies. Dried materials of Boh Black Tea, Lipton Black Tea and Sabah Black Tea from the leaves of Camellia sinensis plant were extracted via reflux using solid-solvent extraction with 70% methanol in distilled water to obtain crude extracts. Total phenolic contents, antioxidative activity and antimicrobial activities of the tea extracts were investigated. The total phenolic content, determined according to the Folin-Ciocalteu method, varied from 83.6709 to 101.3817 mg GAE/g dry weight. Antioxidative activities of the extracts were measured using the Ferric Thiocynate (FTC) method to determine semiquantitatively of the inhibitory capacity against linoleic acid oxidation relative to butylated hydroxytoulene (BHT). The results showed that the three extracts appeared as strong antioxidants comparable to BHT. The relative absorbance values of these three extracts almost similar to each other indicating that they possessed a similar efficiency in inhibitory activity against linoleic acid peroxidation. Results showed that there was a significant positive relationship between the total phenolic contents and anti-oxidation activities of all extracts tested. Antimicrobial activity test was carried out using a disc diffusion method against five bacteria species. The results showed that all of the three extracts showed strong inhibiton activity against S. aureus S 277, B. cereus B 43/04 B (to-15 mm) and moderate range of diameter inhibition zone against S. typhimurium S 1000 and E.coli E 91/026 (1-3 mm). However all of the samples had no bacteriostatic inhibiting activity against P. aeruginosa AT CC 10145. Conclusively, from this study, it is known that black tea could be as effective as green tea as a healthy beverage

Item Type: Academic Exercise
Uncontrolled Keywords: black tea, antioxidant, camellia sinensis plant, antimicrobial activity, phenolic content
Subjects: Q Science > QR Microbiology
Divisions: SCHOOL > School of Science and Technology
Date Deposited: 26 Jun 2013 05:06
Last Modified: 23 Oct 2017 04:53

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