The potential of natural products as effective treatments for allergic inflammation: implications for allergic rhinitis.

The impact of natural products on human health has been enormous, and the study of natural products continues to influence research in the fields of chemistry, biology, and ecology. Historically, the majority of our medicines originate from natural products and their synthetic derivatives, many of which have taught us valuable lessons about biology. While advances in synthetic and combinatorial chemistry have given rise to notable successes in the development of new drugs, the perceived value of natural products in the treatment of allergic disease has yet to be fully explored. The immune system is a highly complex, intricately regulated group of cells whose integrated function is essential to health. Cells of the immune system may interact in a cell-cell manner and may also respond to intercellular messages including hormones, cytokines, and effector molecules produced by various cells. These effector molecules include histamine, kinins, leukotrienes, prostaglandins, and serotonin. The immune system can be modified by diet, pharmacologic agents, environmental pollutants, and naturally occurring food chemicals, such as vitamins and flavonoids. Allergic inflammation is mediated by several types of immune cells all of which can be effected by these naturally occurring bioactive compounds but this review will focus on mast cells and their mediators since these cells are the focal point of allergic reactions such as allergic rhinitis. The molecular mechanisms and scientific validity of some herbal remedies currently used clinically in the treatment of allergic rhinitis will be explored.