Date Published: October 5, 2018
Publisher: Public Library of Science
Author(s): Yuqing Sun, Shi Zhong, Jiaqi Yu, Jianxun Zhu, Dongfeng Ji, Guiyan Hu, Chongming Wu, Yougui Li, Udai P. Singh.
Phellinus igniarius, which is called Sanghuang in Chinese, is a fungal herb widely used in Traditional Chinese Medicine to treat stomachache, inflammation and tumors. Recent studies have demonstrated the antitumor, anti-diabetic, anti-inflammatory and immunity-modulating activities of P. igniarius. In the present study, we investigated that ameliorating effect of the aqueous extract of P. igniarius fruiting body (SH) on dextran sodium sulfate (DSS)-induced colitis in C57BL/6 mice. Treatment with SH (250 and 400 mg/kg) for 8 weeks effectively alleviated the pathological indicators of colitis such as bodyweight reduction, disease activity index score, shortening of colon length and abnormal colon histology. The plasma levels of lipopolysaccharide (LPS) and inflammatory factors such as interleukin-6 (IL-6), IL-1β and tumor necrosis factor (TNF)-α were all significantly reduced. Supplementation of SH (10 mg/L) also inhibited LPS-elicited IL-1β production by RAW264.7 macrophages. Real-time PCR and western blot showed that treatment with SH significantly inhibited the phosphorylation of nuclear factor kappa B inhibitor alpha (IκBα) and decreased the expression of IL-6/IL-1β-maturation genes such as apoptosis-associated speck-like protein (ASC3) and caspase-1 in the colon of DSS-induced colitis mice. These results suggest that SH is adequate for the treatment of colitis. Inhibiting the expression and release of inflammatory factors may participate in the colitis-ameliorating effect of SH.
Inflammatory bowel disease (IBD) is a chronic remittent and relapsing inflammatory condition, which is characterized by chronic inflammation in the colon and mainly comprises ulcerative colitis (UC) and Crohn’s disease (CD). The typical symptoms of IBD are diarrhea, rectal bleeding, intermittent abdominal pain and weight loss, seriously deteriorate the quality of life and lead to increased risk of colon cancer. The precise pathogenesis of IBD has not been completely elucidated, but the chronic relapsing inflammation is implicated to the exaggerated immune response to gut microbiota. This dysregulated response results in increased expression and secretion of pro-inflammatory cytokines, such as tumor necrosis factor-α (TNF-α), interferon-γ, interleukin (IL)-1β and IL-6, which ultimately damages colon tissues.
Although multiple pharmacological activities of P. igniarius extract have been well-documented [7–14] but its effect on colitis is largely unknown. Recently, Song et al  reported that the ethanol and ethyl acetate extract of P. linteus exerted adequate colitis-ameliorating effect in DSS-induced colitis mice . However, P. igniarius is traditionally used as decoction not by ethanol extraction. Therefore, whether the traditional usage of P. igniarius is beneficial for the treatment of colitis is remained to be elucidated.