Inhibition of bacterial DNA-dependent RNA polymerases and restriction endonuclease by UV-absorbing components from propolis.

Several UV-absorbing substances inhibiting the DNA-dependent RNA polymerases of Escherichia coli and Streptomyces aureofaciens, as well as the restriction endonuclease Eco RI have been isolated from the water-soluble extract of Propolis by two-dimensional paper chromatography. The inhibition of bacterial RNA-polymerases by the components of Propolis was probably due to the loss of their ability to bind to DNA. The general characteristic of the UV-absorbing component of Propolis with the most pronounced inhibitory effect upon transcription in vitro is described.