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. 1998 Oct;63(2-4):147-57.
doi: 10.1016/s0378-1135(98)00242-9.

An in vitro study of theaflavins extracted from black tea to neutralize bovine rotavirus and bovine coronavirus infections

K J Clark  1 , P G Grant, A B Sarr, J R Belakere, C L Swaggerty, T D Phillips, G N Woode
Affiliations

An in vitro study of theaflavins extracted from black tea to neutralize bovine rotavirus and bovine coronavirus infections

K J Clark et al. Vet Microbiol. 1998 Oct.

Abstract

Crude theaflavin was extracted from black tea and then fractionated by HPLC into five components (initial peaks (IP), TF1, TF2A, TF2B, and TF3). The crude extract and the various fractions of theaflavin were collected and tested, individually and in combination, for antirotaviral activity. The mean effective concentration (EC50) was calculated and compared. Activity varied from the most active being the uncharacterized theaflavin-like initial peaks (IP) with an EC50 of 0.125 microgram/ml to the least active being theaflavin-3 monogallate (TF2A) with an EC50 of 251.39 micrograms/ ml. The combination of TF1 + TF2A + TF2B + TF3 was more active than the sum of the activities of these four fractions individually, indicating synergism among the peaks. Only the crude extract was assayed for activity against coronavirus; the EC50 was 34.7 micrograms/ml.

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Figures

Fig. 1
Fig. 1
Chromatograms of crude extract of black tea.
Fig. 2
Fig. 2
Chemical structures of TF1, TF2A, TF2B, TF3.
Fig. 3
Fig. 3
Proposed molecular structures of TF1, TF2A, TF2B, TF3.
See this image and copyright information in PMC

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