Anti-inflammatory effect of foods and crude drugs in relation to bitter and spicy tastes

Abstract

In Kampo medicine as well as traditional Chinese medicine, each crude drug is classified by four properties (cold, cool, warm, and heat), five tastes (sour, bitter, sweet, spice, and salt) based on the Yin-yang and five elements (wood, fire, earth, metal, water) theory. The four properties and five tastes are greatly related to the medicinal efficacy of the crude drug in Kampo medicine. The pharmacological function of crude drugs is called "Yakuno" in Japanese. Examples of Yakuno include various functions such as clearing heat and removing blood stasis. Crude drugs with properties classified as cold or cool have the function to clear heat as they cool the body. Crude drugs classified as bBitter also have the function to clear heat. We speculated that anti-inflammatory constituents are included in crude drugs and food that are classified as cold or cool in property and bitter in taste. The suppression of nitric oxide (NO) production, which is a pro-inflammatory mediator, is correlated with the anti-inflammatory activity of drugs. Therefore, studies of anti-inflammatory constituents have been conducted with the suppressive effect of NO production in primary cultured hepatocytes as an indicator. Each extract or constituent was added to the medium, and NO levels in the medium were assayed by Griess method. The constituents that suppressed NO production in the hepatocytes were isolated from crude drugs with cold or cool property, such as coptis rhizome, phellodendron bark, lonicera flower, and cherry bark. Other groups isolated the NO-suppressing constituents from crude drugs with cold or cool property, such as scutellaria root, gardenia fruit, and mountain kidney. Next, we isolated the NO-suppressing constituents from the crude drugs or foods with bitter taste: Coptis Rhizome, phellodendron Bark, and Asparagus officinalis stem. Other NO-suppressing constituents were also isolated from crude drugs and foods with Bitter taste: Atractylodes Lancea Rhizome, Moutan Bark, fruit of Momordica charantia, Rhizome of Curcuma longa, Leaf of Camellia sinensis, and chrysanthemum flower. Based on these studies, crude drugs and foods with cold or cool property and those with bitter taste, may possess anti-inflammatory effects. Furthermore, many pungent constituents from foods have been reported to have an anti-inflammatory effect. Therefore, in studying anti-inflammatory constituents of foods and crude drugs, it seems that information on whether those properties are cold or cool and whether those tastes are bitter or spicy is useful.