Abstract
Inhibitory effects of four kinds of tea catechins, (-)-epicatechin (EC), (-)-epigallocatechin (EGC), (-)-epicatechin gallate (ECg), and (-)-epigallocatechin gellate (EGCg), against TMV and CMV were investigated.
Nicotiana tabacum (Ky-57) was used as the assay host for CMV, and tomato and N. glutinosa for TMV. Each of four tea catechins was added at a concentration of 5mg/ml to the sap expressed from leaves of tobacco or cucumber systemically infected with the virus, and inoculated on the leaves of the assay plants.
When each of four tea catechins was added at a concentration of 0.5% to 1% gelatin solution, (-) EC and (-) EGC did not give precipitation, whereas (-) ECg and (-) EGCg immediately produced precipitates. The same results were obtained when the above described virus inocula were used instead of the gelatin solution.
(-) ECg and (-) EGCg, which easily combine with water-soluble protein, were more inhibitory against infection with CMV than (-) EC and (-) EGC, and no symptom appeared even 30 days after inoculation.
No symptom appeared also in both systemic and local lesion hosts when inoculated with TMV plus (-) ECg or (-) EGCg.
The number of local lesions on inoculated leaves decreased in proportion to the concentration of (-) ECg and (-) EGCg in the inoculum, and no lesion was produced at 0.5% of catechins.
