Inhibition of Chemical Mediator Release by Dry Herb Extracts

Abstract

Chemical mediator release inhibitory activity, DPPH radical scavenging activity, and deoxyguanosine oxidation inhibitory activity of 14 dried herb extracts were examined. Their total polyphenol and flavonoid (flavonol compound) content was also determined. Extracts of peppermint (Mentha piperita), laurel (Laurus nobilis), basil (Ocimum basilicum) and rosemary (Rosmarinus officinalis) inhibited histamine release from rat peritoneal cells (PCs) by less than 50%, while those that contain large amounts of polyphenol strongly inhibited it. Extracts of thyme (Thymus vulgaris), spearmint (Mentha spicata), marjoram (Origanum majorana), sage (Salvia officinalis), oregano (Origanum vulgare), peppermint, freeze-dried thyme, rosemary (sun or freeze-dried) also inhibited leukotriene (LT)B₄ release by about 50%. Those extracts that suppressed LTB₄ release tended to contain large amounts of polyphenols and flavonoids. Extracts that suppressed histamine and LTB₄ release showed high DPPH radical scavenging and deoxyguanosine oxidation inhibitory activities. Thus, in herb extracts possessing antioxidant activity, polyphenols may play an important role in the suppression of chemical mediator release by scavenging radicals.