Three undescribed dimeric ferulates from the culture broth of Phellinus linteus and their dengue virus type-2 inhibition activity

Several members of the genus Phellinus have been used as traditional medicine for treating various diseases. They produce unique yellow pigments composed of a styrylpyrone class of compounds. Styrylpyrones exhibit various biological activities. The styryl group is derived from phenylalanine via cinnamic acid, p-coumaric acid, and caffeoyl-CoA pathways, whereas the pyrone ring is derived from acetate. In a feeding experiment using ferulic acid, a phenylpropanoid, three undescribed dimeric ferulates designated as phellidiferulates A-C were isolated from culture broth of P. linteus. Their structures were determined by spectroscopic methods. These compounds exhibited anti-viral activities against dengue virus type 2 (DENV-2) with IC₅₀ values ranging from 0.12 to 0.18 µg/mL.