Anti-allergic potential of herbs and herbal natural products - activities and patents.

The increase of allergic diseases has accompanied the global population growth and the major challenge is to reduce morbidity. The currently available treatments present limitations regarding efficacy and safety. Hence, patients with chronic allergic conditions seek alternatives to achieve better control of symptoms. Many natural products have been identified as potential anti-allergic agents. In addition, plant formulations have demonstrated, in general, to be safe in clinical trials and demonstrate additional effects along with Western medicines such as synergism and modulation of the immune system. It is known that plants represent a source of new therapeutic agents and some of them have shown mechanisms of action similar to synthetic agents. However, in general, herbs and their combination are patented mainly by Asian countries to be used in food and drinks or cosmetics and dietary supplements and the anti-allergic mechanisms of action are not yet fully elucidated. In this review, we highlight relevant patent and studies with cultivated plants, plant formulations, and secondary metabolites that have been evaluated with respect to its anti-allergic potential.