The inhibition effect of flavonoids extracted from Bidens pliosa L. on TMV

The antiTMV activities of flavonoids extracted from Bidens pliosa L. were determined. The results were as follows: infectivity of Tobacco mosaic virus (TMV) in Nicotiana glutinosa was strongly inhibited by flavonoids from B. pliosa L.; the inhibition rate was 91.3% after incubated with flavonoids at 100 μg·mL-1, but it could not inhibit multiplication of TMV in the infected leaf discs; the flavonoids could bind TMV coat protein based on routine PAGE; the infectivity of TMV could be recovered by dialyzing from incubations with flavonoids or extracting flavonoids from virus particles; the flavonoids had no direct viricidal effect; flavonoids could reduce infectivity of TMV and retard symptom expression if sprayed in N. tobacum at the time of 12 h before inoculation.