Purification and characterization of a novel antioxidant Phelligridin LA produced by Inonotus baumii

BACKGROUND The fruit body of medicinal fungus, Sanghuang ( Inonotus baumii ), is a source of diverse metabolites with health‐promoting efficacy through varying mechanisms. The low efficiency of fruit body production and failure to discover valuable metabolites have severely limited more extensive applications. RESULTS A novel compound was discovered and identified as (6,6′‐bis(( E )‐3,4‐dihydroxystyryl)‐4,4′‐dihydroxy‐2 H ,2′ H ‐[3,3′‐bipyran]‐2,2′‐dione (named as Phelligridin LA, PLA). The compound exhibited antioxidant activity against free radicals (DPPH•, •OH, •O 2 , and ABTS• + ). The IC 50 values of PLA and vitamin C were determined as 18.62 and 11.26 μmol L −1 (DPPH•), 222.56 and 718.48 μmol L −1 (•OH), 611.41 and 340.11 μmol L −1 (•O 2 ), 73.33 and 44.31 μmol L −1 (ABTS• + ), which demonstrated that PLA was an efficient scavenger of •OH radical. CONCLUSION PLA is a novel antioxidant metabolite purified from the fermentation broth of Sanghuang, which proved that the biomass produced with fermentation was a good source for metabolite isolation. A feasible process was established to obtain this valuable ingredient from the medicinal fungus. This report exemplifies the exploitation of Sanghuang in the context of modern natural product discovery. © 2020 Society of Chemical Industry