Propolis: recent advances in chemistry and plant origin

New information published since 1995 about propolis constituents is reviewe d. The available information on the biological action of new found componen ts is presented. Recent publications are reviewed on propolis of native Sou th American stingless bees. The plant sources of bee glue are discussed, ta king into consideration data based on reliable chemical evidence including comparisons between propolis samples and plant material. Some aspects of th e chemical standardization of propolis are discussed.