Anti-Gout Effects of the Medicinal Fungus Phellinus igniarius in Hyperuricaemia and Acute Gouty Arthritis Rat Models

Background:Phellinus igniarius (P. igniarius) is an important medicinal and edible fungus in China and other Southeast Asian countries and has diverse biological activities. This study was performed to comparatively investigate the therapeutic effects of wild and cultivated P. igniarius on hyperuricaemia and gouty arthritis in rat models.Methods: UPLC-ESI-qTOF-MS was used to identify the chemical constituents of polyphenols from wild P. igniarius (WPP) and cultivated P. igniarius (CPP). Furthermore, WPP and CPP were evaluated in an improved hyperuricaemia rat model induced by yeast extract, adenine and potassium oxonate, which was used to examine xanthine oxidase (XO) activity inhibition and anti-hyperuricemia activity. WPP and CPP therapies for acute gouty arthritis were also investigated in a monosodium urate (MSU)-induced ankle swelling model. UHPLC-QE-MS was used to explore the underlying metabolic mechanisms of P. igniarius in the treatment of gout.Results: The main active components of WPP and CPP included protocatechuic aldehyde, hispidin, davallialactone, phelligridimer A, hypholomine B and inoscavin A as identified by UPLC-ESI-qTOF-MS. Wild P. igniarius and cultivated P. igniarius showed similar activities in reducing uric acid levels through inhibiting XO activity and down-regulating the levels of UA, Cr and UN, and they had anti-inflammatory activities through down-regulating the secretions of ICAM-1, IL-1β and IL-6 in the hyperuricaemia rat model. The pathological progression of kidney damage was also reversed. The polyphenols from wild and cultivated P. igniarius also showed significant anti-inflammatory activity by suppressing the expression of ICAM-1, IL-1β and IL-6 and by reducing the ankle joint swelling degree in an MSU-induced acute gouty arthritis rat model. The results of metabolic pathway enrichment indicated that the anti-hyperuricemia effect of WPP was mainly related to the metabolic pathways of valine, leucine and isoleucine biosynthesis and histidine metabolism. Additionally, the anti-hyperuricemia effect of CPP was mainly related to nicotinate and nicotinamide metabolism and beta-alanine metabolism.Conclusions: Wild P. igniarius and cultivated P. igniarius both significantly affected the treatment of hyperuricaemia and acute gouty arthritis models in vivo and therefore may be used as potential active agents for the treatment of hyperuricaemia and acute gouty arthritis.

Purification, Characterization and Immunomodulatory Activities of Polysaccharides from Mulberry Leaf Fermented with Phellinus igniarius

Phellinus igniarius is a rare and precious medicinal fungus, displaying an outstanding physiological effect, especially the immunomodulatory effects. Previous studies indicated that water-soluble crude polysaccharide (MPFP) was obtained from mulberry leaf fermented with Phellinus igniarius. In vitro cell assay revealed that MPFP showed higher immunomodulatory activity than that of mulberry leaves polysaccharide (MP) and Phellinus igniarius mycelial polysaccharide (PP). Therefore, in this study, structure and immunomodulatory activity of MPFP were measured, a novel polysaccharide named MPFP2-1 was separated through DEAE-52 cellulose column and SephadexG-100 gel-filtration chromatography. Monosaccharide composition analysis showed that MPFP2-1 was mainly composed of L-rhamnose and D-glucose with the molar ratio of 1.0:5.4. The average molecular weight was 50.3 kDa by high performance gel permeation chromatography (HPGPC). FT-IR spectrum showed that MPFP2-1 contained a characteristic absorption peak of polysaccharide. The NMR spectrum indicated MPFP2-1 contained 1 → 6 glucosidic bond. In vitro immunomodulatory assay revealed that MPFP2-1 significantly enhanced the macrophages proliferation, stimulated the macrophages phagocytic capacity, as well as induced NO and TNF-a generation. We further discovered that MPFP2-1 stimulated iNOS and TNF-α protein expression in RAW264.7 cells by western blotting. The results are in agreement with ELISA. All the results suggest that MPFP2-1 possesses potent immunomodulatory activity and could be taken forward as new products for medicines.

Screening for proteins related to the biosynthesis of hispidin and its derivatives in Phellinus igniarius using iTRAQ proteomic analysis

Background Hispidin (HIP) and its derivatives, a class of natural fungal metabolites, possess complex chemical structures with extensive pharmacological activities. Phellinus igniarius, the most common source of HIP, can be used as both medicine and food. However, the biosynthetic pathway of HIP in P. igniarius remains unclear and we have a limited understanding of the regulatory mechanisms related to HIP. In this work, we sought to illustrate a biosynthesis system for hispidin and its derivatives at the protein level. Results We found that tricetolatone (TL) is a key biosynthetic precursor in the biosynthetic pathway of hispidin and that its addition led to increased production of hispidin and various hispidin derivatives. Based on the changes in the concentrations of precursors and intermediates, key timepoints in the biosynthetic process were identified. We used isobaric tags for relative and absolute quantification (iTRAQ) to study dynamic changes of related proteins in vitro. The 270 differentially expressed proteins were determined by GO enrichment analysis to be primarily related to energy metabolism, oxidative phosphorylation, and environmental stress responses after TL supplementation. The differentially expressed proteins were related to ATP synthase, NAD binding protein, oxidoreductase, and other elements associated with electron transfer and dehydrogenation reactions during the biosynthesis of hispidin and its derivatives. Multiple reaction monitoring (MRM) technology was used to selectively verify the iTRAQ results, leading us to screen 11 proteins that were predicted to be related to the biosynthesis pathways. Conclution These findings help to clarify the molecular mechanism of biosynthesis of hispidin and its derivatives and may serve as a foundation for future strategies to identify new hispidin derivatives.

Screening for proteins related to the biosynthesis of hispidin and its derivatives in Phellinus igniarius using iTRAQ proteomic analysis

Background: Hispidin (HIP) and its derivatives, a class of natural fungal metabolites, possess complex chemical structures with extensive pharmacological activities. Phellinus igniarius, the most common source of HIP, can be used as both medicine and food. However, the biosynthetic pathway of HIP in P. igniarius remains unclear and we have a limited understanding of the regulatory mechanisms related to HIP. In this work, we sought to illustrate a biosynthesis system for hispidin and its derivatives at the protein level. Results: We found that tricetolatone (TL) is a key biosynthetic precursor in the biosynthetic pathway of hispidin and that its addition led to increased production of hispidin and various hispidin derivatives. Based on the changes in the concentrations of precursors and intermediates, key timepoints in the biosynthetic process were identified. We used isobaric tags for relative and absolute quantification (iTRAQ) to study dynamic changes of related proteins in vitro. The 270 differentially expressed proteins were determined by GO enrichment analysis to be primarily related to energy metabolism, oxidative phosphorylation, and environmental stress responses after TL supplementation. The differentially expressed proteins were related to ATP synthase, NAD binding protein, oxidoreductase, and other elements associated with electron transfer and dehydrogenation reactions during the biosynthesis of hispidin and its derivatives. Multiple reaction monitoring (MRM) technology was used to selectively verify the iTRAQ results, leading us to screen 11 proteins that were predicted to be related to the biosynthesis pathways.Conclusion: These findings help to clarify the molecular mechanism of biosynthesis of hispidin and its derivatives and may serve as a foundation for future strategies to identify new hispidin derivatives.