Screening anti-gout compounds from Phellinus igniarius by ultrafiltration liquid chromatography mass spectrometry based on evaluation of an in vitro method combined with enzymatic reaction

Aqueous extract of Phellinus igniarius ameliorates hyperuricemia and renal injury in adenine/potassium oxonate-treated mice

Phellinus igniarius is an important medicinal and edible fungus with diverse biological activities. This study aimed to investigate the effects of aqueous extract from P. igniarius (API) on the treatment of hyperuricemia (HUA) and related kidney damage. The chemical constituents of API were determined. The therapeutic effects of API on HUA and renal injury were assessed in adenine/potassium oxonate (PO)-treated mice. The constituent analysis of API revealed a predominance of polysaccharides (33.4 %), followed by total flavonoids (9.1 %), and total triterpenoids (3.5 %). Compared to control, the adenine/PO treatment greatly elevated serum uric acid (UA) levels but this elevation was attenuated by API. In the liver, the expression and activity of xanthine oxidase (XOD) were increased by HUA which were diminished by API. Furthermore, API was found to enhance the expression of UA transporter ABCG2 in the kidney and intestine of HUA mice, suggesting elevating UA excretion. Additionally, API ameliorated HUA-induced renal injury, as indicated by reduced serum BUN/creatinine levels, decreased glomerular and tubular damage, and lowered fibrotic levels. Network pharmacology analysis predicted that P. igniarius may regulate mitochondrial function to improve HUA-related renal injury. This prediction was then substantialized by the API-induced upregulation of NAD+/NADH ratio, ATP level, SOD2 activity, and expression of SOD2/PCG-1α/PPARγ in the kidney of HUA mice. Our results demonstrate that API may effectively ameliorate HUA by reducing UA production in the liver and enhancing UA excretion in the kidney and intestine, and it might be a potential therapy to HUA-related renal injury.

Pathology, target discovery, and the evolution of XO inhibitors from the first discovery to recent advances (2020-2023)

Hyperuricemia, a disease characterized by elevation of serum uric acid level beyond 6 mg/dL. This elevation led to appearance of symptoms from joint pain to gout and from gout to difficulty in mobility of the patient. So, in this review, we have summarized the pathology of hyperuricemia, discovery of target and discovery of first XO inhibitor. At last, this review provides in-sights about the recently discovered as natural XO inhibitors, followed by design, structure activity relationship and biological activity of synthetic compounds as XO inhibitors discovered between 2020 and 2023 years. At last, the pharmacophores generated in this study will guide new researchers to design and modify the structure of novel XO inhibitors.

Polysaccharide extracted from cultivated Sanghuangporous vaninii spores using three-phase partitioning with enzyme/ultrasound pretreatment: Physicochemical characteristics and its biological activity in vitro

Sanghuangporous vaninii, as a valuable dietary supplement and medicinal ingredient, contains abundant bioactive polysaccharides that have health-promoting effects. In the present study, four polysaccharides (SVSPs-C, SVSPs-E, SVSPs-U, and SVSPs-E/U) were extracted for the first time from S. vaninii spores by three-phase partitioning (TPP), enzyme pretreatment before TPP (E-TPP), ultrasonic pretreatment before TPP (U-TPP), and enzyme pretreatment followed by ultrasonic before TPP (E/U-TPP) methods, respectively. Their physicochemical characteristics and in vitro pharmacological functions were determined and compared. Results showed that four TPP-based extraction methods had remarkable impacts on the extraction yield, chemical properties, monosaccharide compositions, and molecular weights (Mw) of SVSPs. Specifically, SVSPs-E/U obtained by E/U-TPP showed the highest extraction yield (25.40 %), carbohydrate content (88.50 %), and the lowest protein content (0.86 %). The four SVSPs had high-Mw (183.8-329.1 kDa) and low-Mw (23.0-156.4 kDa) fractions and mainly consisted of galactose, glucose, and mannose with different contents. In vitro bioactivities assays indicated that SVSPs-E/U possessed stronger antioxidant, hypoglycemic, hypouricemic, immunostimulatory, and antitumor activities than those of SVSPs-C, SVSPs-E, and SVSPs-U. Therefore, our results provide an efficient and promising extraction technique for bioactive polysaccharides from S. vaninii spores, as well as SVSPs had the potential to be applied in functional food, pharmaceutical, and cosmetics fields.

Studies on the interaction mechanism between xanthine oxidase and osmundacetone: Molecular docking, multi-spectroscopy and dynamical simulation

Xanthine oxidase (XO) is a key enzyme in uric acid production, and its molybdopterin (Mo-Pt) domain is an important catalytic center when xanthine and hypoxanthine are oxidated. It is found that the extract of Inonotus obliquus has an inhibitory effect on XO. In this study, five key chemical compounds were initially identified using liquid chromatography-mass spectrometry (LC-MS), and two compounds, osmundacetone ((3E)-4-(3,4-dihydroxyphenyl)-3-buten-2-one) and protocatechuic aldehyde (3,4-dihydroxybenzaldehyde), were screened as the XO inhibitors by ultrafiltration technology. Osmundacetone bound XO strongly and competitively inhibited XO with a half-maximal inhibitory concentration of 129.08 ± 1.71 μM, and its inhibition mechanism, was investigated. Osmundacetone and XO via static quenching and spontaneously bound with XO with high affinity, primarily via hydrophobic interactions and hydrogen bonds. Molecular docking studies showed that osmundacetone was inserted into the Mo-Pt center and interacted with hydrophobic residues of Phe911, Gly913, Phe914, Ser1008, Phe1009, Thr1010, Val1011, and Ala1079 of XO. In summary, these findings suggest that provide theoretical basis for the research and development of XO inhibitors from Inonotus obliquus.

Anti-gout activity and the interaction mechanisms between Sanghuangporus vaninii active components and xanthine oxidase

Xanthine oxidase (XO) plays a critical role in the progression of gout. We showed in a previous study that Sanghuangporus vaninii (S. vaninii), a perennial, medicinal, and edible fungus traditionally used to treat various symptoms, contains XO inhibitors. In the current study, we isolated an active component of S. vaninii using high performance countercurrent chromatography and identified it as davallialactone using mass spectrometry with 97.726 % purity. A microplate reader showed that davallialactone had mixed inhibition of XO activity with a half-inhibitory concentration value of 90.07 ± 2.12 μM. In addition, the collision between davallialactone and XO led to fluorescence quenching and conformational changes in XO, which were mainly driven by hydrophobicity and hydrogen bonding. Molecular simulations further showed that davallialactone was located at the center of the molybdopterin (Mo-Pt) of XO and interacted with amino acid residues Phe798, Arg912, Met1038, Ala1078, Ala1079, Gln1194, and Gly1260, suggesting that entering the enzyme-catalyzed reaction was unfavorable for the substrate. We also observed face-to-face π-π interactions between the aryl ring of davallialactone and Phe914. Cell biology experiments indicated that davallialactone reduced the expression of the inflammatory factors, tumor necrosis factor alpha and interleukin-1 beta (P < 0.05), can effectively alleviate cellular oxidative stress. This study showed that davallialactone significantly inhibits XO and has the potential to be developed into a novel medicine to prevent hyperuricemia and treat gout.

Anti-Inflammatory and Hypouricemic Effect of Bioactive Compounds: Molecular Evidence and Potential Application in the Management of Gout

Gout is caused by the deposition of monosodium urate crystals in the joint and represents the most common form of inflammatory arthritis in men. Its prevalence is rising worldwide mainly due to the increase of risk factors associated with the disease, in particular hyperuricemia. Besides gout, hyperuricemia leads to an increased inflammatory state of the body with consequent increased risk of comorbidities such as cardiovascular diseases. Increasing evidence shows that bioactive compounds have a significant role in fighting inflammatory and immune chronic conditions. In gout and hyperuricemia, these molecules can exert their effects at two levels. They can either decrease serum uric acid concentrations or fight inflammation associated with monosodium urate crystals deposits and hyperuricemia. In this view, they might be considered valuable support to the pharmacological therapy and prevention of the disease. This review aims to provide an overview of the beneficial role of bioactive compounds in hyperuricemia, gout development, and inflammatory pathways of the disease.

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.