A Preliminary Study of the Absorption and Metabolism of Temperate Propolis by Human Subjects

Abstract

Temperate propolis is collected by bees from the sticky secretions produced by the buds of poplar species. It is used to coat and seal the hive thus protecting against infections. Extensive research indicates that propolis has strong anti-protozoal activity. There have been some large clinical trials testing propolis against a variety of conditions but despite there is no information on whether or not the active components in propolis are absorbed by humans. In order to answer this question, a small study was carried out in order to determine whether or not propolis components could be detected in the urine of 5 human subjects taking a small dose of propolis tincture. In two of the subjects, levels of several of the flavonoids present in the propolis tincture many times above the baseline levels were detected following hydrolysis of the urine samples with a glucuronidase/sulfatase. Analysis of urine samples prior to hydrolysis indicated the presence of glucuronides and sulfates of the main flavonoids in propolis. Flavonoid absorption occurred to some degree in all subjects, apparent lower levels of flavonoid absorption in 3 out of five subjects might indicate genuine differences in level of absorption between subjects.