Herbal medicine for obesity treatment: a review

The obesity drug development is presently not a bright and successful story. So far, drugs reported to be effective, either from synthetic or natural sources, mostly stimulated controversy due to serious adverse effects, which ended with stopping clinical trials or even withdrawal from the market. However, obesity and its comorbidity have become rapidly a major problem in both developed and developing countries. This has encouraged pharmaceutical companies and academia to keep on struggling on developing novel effective but safe obesity drugs, and on characterizing novel obesity drug targets. From existing scientific work on obesity drug discovery and commercial slimming preparations, compounds originating from nature, especially from plants, seem to be the first choice. Traditional belief that herbal medicine is safer than synthetic ones is one of the classical arguments, although scientifically this is not always true (ban on Ephedra, for example). But in general, it has been widely acknowledged that plant compounds, with their unique scaffolds and rich diversity are an unlimited source of novel lead compounds. All work summarized in this review is focused on screening plant materials by targeting various important pathways related to energy homeostasis, either by in-vivo or in-vitro experiments. So far only a few of them have come quite far in the development track, leading to some patented products (e.g. Hoodia sp.). The mechanisms of action of these preparations have been elucidated until gene