Allergic reaction is a hypersensitive response caused by immunoglobulin E (IgE)-dependent mast cell activation. In response to IgE receptor cross-linking or other stimuli, mast cells initiate exocytosis of the contents of secretory granules. These include vasoactive amines, arachidonic acid metabolites, chemokines, and cytokines [1, 2]. These pro-inflammatory mediators are responsible for activating mast cells in allergic inflammation and the hypersensitive response [3–6]. Therefore, an agent or agents capable of attenuating the production of these mediators may be used as anti-inflammatory/anti-allergic agents. Since the notion that a daily intake of certain food having anti-allergic activity has the potential to reduce or eliminate the need for drugs is generally accepted, the anti-inflammatory/anti-allergic activities of the chungkookjang (CKJ) have been screened for this purpose .
Soybean-based fermented foods, such as CKJ is a Korean traditional food. It is prepared by fermenting unsalted soybeans with Bacillus subtilis for several days. It has a long history of popular use by the Korean people and is sometimes used for topically for inflammatory skin disorders. Several isoflavonoids such as genistein and daidzein have been identified among the bioactive compounds in the CKJ . During the fermentation period, the content of the flavonoid aglycones increases because of hydrolysis of the flavonoid glycosides . The CKJ is also containing the poly-gamma-glutamic acid (gamma-PGA). Gamma-PGA is an anionic polymer that is composed of D- and L-glutamic acid units connected by gamma-amide linkages between alpha-amino and gamma-carboxylic acid groups . Gamma-PGA is mainly produced by Bacillus subtilis during fermentation processes of soybeans and not present in humans . Gamma-PGA is water soluble, biodegradable, edible and non-toxic properties, raising interest in a broad range of industries including food and cosmetics . Furthermore, recent reports have indicated anti-allergic activity and immune modulatory activities of gamma-PGA [7, 13–16].
Histamine is one of the important mediators that elicit a variety of symptoms such as wheal and flare response. Since these histamine-related symptoms provoke the urge to scratch, often impairing the quality of life, measures to suppress and control these symptoms are required. In the development of a new anti-histamine, the histamine-induced wheal and flare skin test has been used most frequently. The histamine-induced wheal and flare test is based on the measurement of local swelling caused by plasma extravasation (wheal) and reflex vasodilatation (flare) after histamine challenge . Therefore, the histamine skin prick test may be useful for assessing aspects of drug activity during the early clinical development of a new anti-histamine.
The aim of this study is to evaluate the efficacy and safety of the CKJ, a dietary supplement for the treatment of allergic skin symptoms. This study will be first pilot study about the improvement of skin hypersensitivity reaction of the CKJ in healthy volunteers. The results of this study will give us the clinical of biochemical parameters such as IgE, histamine, and cytokines between the placebo and CKJ groups. On the basis of the results, we will suggest the optimal design, precise sample size, and primary outcome for a further large scale RCT.