An inulin-type polysaccharide from Atractylodis Macrocephalae Rhizoma can relieve psoriasis

Atractylodis Macrocephalae Rhizoma (AMR), an herb often found in compounded remedies for psoriasis , is rich in polysaccharides . However, the beneficial effects of AMR polysaccharides on psoriasis remain obscure. In this study, an inulin-type fructan-labelled AMP was extracted from the AMR. AMP has a molecular weight of 5.84 kDa and comprises fructose, glucose, and arabinose at a molar ratio of 93:5:2. Methylation and NMR analyses revealed that AMP comprises a linear backbone of 2,6-linked Fru f or 1,2-linked Fru f with branching 1,2,6-linked Fru f and terminates in T-Glc p. Animal studies verified that AMP can improve imiquimod-induced psoriasis-like skin lesions and downregulate the Il-17a , Il-23 , Il-22 , Il-6 , Il-12 , and Tnf-α gene expression. Furthermore, we elucidated the underlying mechanisms using cellular experiments. The ability of AMP to inhibit hyperproliferation and the overexpression of TNF-α , IL-6 , and IL-23 genes in human immortal keratinocyte cells (HaCaT) stimulated by lipopolysaccharide was demonstrated. These results indicate that AMP may directly target keratinocytes to suppress excessive proliferation and contribute to anti-inflammatory responses, potentially by blocking the activation of the PI3K/AKT/mTOR pathway. In summary, AMP has demonstrated potential as a prospective treatment strategy for psoriasis. • AMP is a promising complementary drug for the treatment of psoriasis • AMP can treat psoriasis through direct action on keratinocytes rather than through other indirect actions. • AMP targeted mTOR was found for the first time. • An inulin-type AMP exhibits an immunosuppressive effect