Antitumor Activity of Propolis: Recent Advances in Cellular Perspectives, Animal Models and Possible Applications

Propolis is a product of the bee Apis mellifera with interesting biological activities reported. Among these, there are a large number of articles that suggest an anti-tumor effect. The ultimate purpose of these contributions is to translate into the development of products applicable to patients. Although there are many studies related to this topic, it is important to recognize a hierarchic order among them related to the caliber of their conclusions. Thus, we can recognize a large number of studies that use tumor cells; something less in experimental animals, and finally a small amount of studies in people. In this article, we review the latest advances in this subject from these three perspectives: in vitro studies, in animals, and in people. While studies in cell cultures focus on describing the molecular processes where propolis extracts may have action, studies in experimental animals indicate the effectiveness in physiological processes, as well as synergistic and palliative effects to conventional therapy; application routes and formulations. In this review, we propose to summarize the main experimental aspects of these models and to show the importance of a concordance between these perspectives and their real contribution in the potential use of products applicable to people.