Soybean: a Potential Antipsoriasis Agent

Psoriasis is a chronic hyperproliferative skin disease, which affects approximately 2% to 4% of the general population. This immune-mediated disorder is characterized by erythematous scaling plaques ranging extensively in size on the scalp, elbows, knee, and other surfaces of the skin (1). Importantly, genetic, immunohistochemical, and pharmacologic investigations support a prominent role for nuclear factor kappa B (NFκB) pathway in patho-physiology of psoriasis (2). Numerous dermatological evidences indicate that tumor necrosis factor (TNF)-α is the pivotal immune mediator involved in psoriasis pathogenesis. This inflammatory cytokine induces an-tiapoptotic proteins in psoriatic skin (3, 4). Interleukin (IL)-1β and IL-6 are unanimously believed to be important in psoriasis disease. Of note, genetic polymorphisms related to IL-6 genes have a relationship with psoriasis that could have a potential effect on disorder counseling and management (5). IL-8 is a chemotactic pro-inflammatory cytokine for all types of migratory immune cells. Recently , Qazi et al. demonstrated the elevated production of IL-8 and/or its receptors in patients with psoriasis (6). Some scientific documents suggest that tissue angioten-sin converting enzyme (ACE) activity in involved skin is significantly increased in patients with psoriasis. Additionally , assessment of therapeutic efficacy in psoriasis is attributed to determination of tissue ACE activity as a good nonspecific parameter (7). Soybean (Glycine max) has been known as a golden bean (8). It has been established that isoflavones are the most abundant phytoestrogens in soybean and structurally similar to 17 beta-estradiol (9). Genistein is considered as the main isoflavone in soybean and exerts potent anti-in-flammatory (10) and anti-oxidant properties (11). Soybean and genistein substantially have been safely used at high levels in several Asian populations in many centuries and play a brilliant role in health promotion (12). Notably, it has been clarified that genistein exerts antiproliferative activity by inhibiting NFκB signaling (13). There is a great deal of immunological evidence that genistein modulates inflammatory responses by reducing production and expression of pro-inflammatory biomarkers such as TNF-α, IL-1β, IL-6 and IL-8 (14-16). Xu et al. investigated (in vivo and in vitro) the association between genistein and changes of ACE in the rat model. They reported down-regulation of ACE with a consequent change in circulating levels of angiotensin II (Ang II) (17). Human neutrophil elastase is a serine protease, which is present in its active form in inflamed tissue as well as psoriatic lesions. It has been identified that genistein could inhibit neutrophil elastase release (18). To …