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.