Propolis research and the chemistry of plant products

Propolis is a honeybee product, composed mainly of wax and resins. The latter have a plant origin and contain substances with biological activity. The composition of propolis is variable, and many plant substances have been identified for the first time in propolis. Some of these compounds have been recognized as having potential medicinal value, and this has stimulated chemical studies of the corresponding plant sources. Topics covered in this review include the known types of propolis, propolis constituents, evaluation of the biological activities of resin constituents, and determination of plant resin sources.