Quercetin and kaempherol: an argument against the use of podophyllin?

INTRODUCTION: Topical application of podophyllin is a routine procedure in patients with ano-genital warts. Podophyllin is a crude plant extract and is therefore not a well-defined product. It may contain variable amounts of the active lignan podophyllotoxin and the majority of the dry weight of podophyllin is made up of substances never identified. OBJECTIVE: The purpose of the study was to estimate in podophyllin 20% the amounts of two mutagenic substances, quercetin and kaempherol. METHODS: Using high-pressure liquid chromatography the amounts of quercetin and kaempherol were determined in 3 batches of podophyllin 20%. RESULTS: Quercetin and kaempherol constitutes 2.5-3.8% and 6.0-6.4% of podophyllin dry substance, respectively. Podophyllotoxin constitutes in comparison 12.7-13.8% of podophyllin dry substance. CONCLUSION: As approximately 10% of the amount of dry substance in podophyllin 20% is composed of two mutagenic flavonoids, quercetin and kaempherol, efforts should be focused on the production of a well-defined purified podophyllotoxin preparation that may replace podophyllin for clinic use in patients with genital warts. Self-medication with purified podophyllotoxin 0.5% may be considered as first-line treatment in well-instructed patients with external genital warts.