Compounds that interact with nucleic acids exhibit a wide spectrum of therapeutic effects such as antimicrobial, antitumour and antiviral activities. Several biological methods exist for detecting DNA-interacting substances, but most of these are relatively specialized procedures requiring cell culture or microbiological techniques. We have tested the feasibility of a simple HPLC assay method utilizing DNA for the detection of DNA-binding substances in complex mixtures. Most known substances that interact with DNA (e.g. ethidium bromide, daunomycin) were shown to reduce the HPLC signal of free DNA in the chromatogram, in a reproducible and dose-dependent manner. Positive results were also observed when ethidium bromide was artificially mixed with inert compounds in a complex matrix. On...[ Read more ]

Compounds that interact with nucleic acids exhibit a wide spectrum of therapeutic effects such as antimicrobial, antitumour and antiviral activities. Several biological methods exist for detecting DNA-interacting substances, but most of these are relatively specialized procedures requiring cell culture or microbiological techniques. We have tested the feasibility of a simple HPLC assay method utilizing DNA for the detection of DNA-binding substances in complex mixtures. Most known substances that interact with DNA (e.g. ethidium bromide, daunomycin) were shown to reduce the HPLC signal of free DNA in the chromatogram, in a reproducible and dose-dependent manner. Positive results were also observed when ethidium bromide was artificially mixed with inert compounds in a complex matrix. On the other hand, substances not considered to interact with DNA showed little or no effect on the DNA signal. Plant extracts were tested for their ability to reduce DNA peak size, and several of them were active (>50% reduction). When further refined, the method may be easily adapted for use as a pre-screen for biological activity.