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In this study, we investigated the effects and mechanisms of Total Saponin of Dioscorea (TSD) on animal experimental hyperuricemia. Mouse and rat hyperuricemic models were made by orally administering yeast extract paste once a day (30 and 20 g/kg, respectively), for 7 days. Yeast would disturb normal purine metabolism by increasing xanthine oxidase (XOD) activity and generating large quantities of uric acid. This model is similar to human hyperuricemia, which is induced by high-protein diets, due to a purine and nucleic acid metabolic disturbance. Another mouse hyperuricemia model was generated by intraperitoneal injection once with uric acid 250 mg/kg or potassium oxonate 300 mg/kg. Potassium oxonate, a urate oxidase inhibitor, can raise the serum uric acid level by inhibiting the decomposition of uric acid. Likewise, injecting uric acid can also increase serum uric acid concentration. The concentration of uric acid in serum or urine was detected by the phosphotungstic acid method, and the activity of XOD was assayed by a test kit. The results showed that TSD (240, 120 and 60 mg/kg, ig) could significantly lower the level of serum uric acid in hyperuricemic mice. TSD (120 and 60 mg/kg, ig) could also lower the level of serum uric acid in hyperuricemic rats, reduce the activity of XOD in the serum and liver of hyperuricemic rats, and increase the level of urine uric acid concentration as well as 24-hour total uric acid excretion. In conclusion, TSD possesses a potent anti-hyperuricemic effect on hyperuricemic animals, and the mechanism may be relevant in accelerating the excretion and decreasing the production of uric acid.

Hyperuricemia is a metabolic disease of the kidney that results in decreased uric acid excretion. Here, we aimed to investigate the effects of ginsenosides and anserine on hyperuricemia and the expression of aquaporin (AQP) 1–4, which are indicators of renal excretion. Ginsenosides and anserine were administered separately or together after the establishment of hyperuricemia with adenine in BALB/c mice. Renal function indexes such as serum uric acid, creatinine, and urea nitrogen were measured in each group of mice, and the expression of AQP1–4 in renal tissues was detected. Serum uric acid and urea nitrogen were decreased in the ginsenoside and the anserine +UA groups. Meanwhile, the uric acid excretion and clearance rate were clearly increased in the co-treatment +UA group ($p<0$.05). Moreover, ginsenosides or anserine ginsenosides or anserine alone and treatment with both increased the expression of AQP1–4; however, the synergistic effects were more significantly enhanced ($p<0$.01). We provide the first reported evidence that ginsenosides and anserine have synergistic effects on uric acid excretion. The improvement in renal function in hyperuricemic mice after treatment with ginsenosides and anserine may result from up-regulation of AQP1–4 expressions.

Uric acid (UA) detection is extremely necessary in both blood serum and urine. High UA concentration in blood serum may induce several diseases. It is very important to develop new methods based on their ecofriendly nature for synthesis new materials used in the detection of UA for diagnosing both hyperuricemia and hypouricemia. This study aimed to synthesis copper, nickel, and copper nickel alloy nanoparticles (NPs) by green voice using Rosmarinus officinalis plant aqueous extract at room temperature. Reduction to CuNPs, NiNPs, and CuNi alloy NPs was confirmed by UV-Vis analysis. The IR analysis is used to identify the chemical group present on the synthesized NPs. Scanning electron microscopy (SEM) shows nearly spherical shape of NPs, X Ray diffraction (XRD) pattern shows face cubic center (fcc) structure and the crystallite range size was estimated to be about 19–49nm. Then, the synthesized NPs were calcined at 500^∘C and characterized by XRD witch confirmed the presence of NPs oxide. These oxidized NPs were used as catalysts to modify carbon paste electrode (CPE) in the study of the electrocatalytic determination of UA by using cyclic voltammetry technique. The result showed that the modified electrodes CPE with 10%CuO, 5%NiO, and 10%CuNiO alloy present the better electrocatalytic activity than uncalcined NPs modified electrodes toward the UA oxidation in phosphate buffer ($\mathrm{\text{pH}}=6$), and exhibited oxidation potential peaks at 515, 541, and 481mV${}_{SCE}$, respectively. The 10%CuNiO/CPE electrode gives a good sensitivity (17.58$\mu$ AmM${}^{-1}$) towards UA oxidation compared with the 10%CuO/CPE (6.83$\mu$ AmM${}^{-1})$ and 5%NiO/CPE (10.74$\mu$AmM${}^{-1}$) electrodes. The detection limits were found to be equal to 100, 100, and 50$\mu$ M for 10%CuO/CPE, 5%NiO/CPE, and 10%CuNiO/CPE, respectively, in awide range of UA concentration. These electrodes also exhibited a high selectivity towards UA in the presence of other interference as well as can be applied for the detection of UA in human urine.

Selectivity is significant to the practical applications of electrochemical biosensors in clinical and diagnostic field. In this paper, porous CeO${}_{2-x}$/C nanorods (NRs) derived from Ce-based metal organic framework (MOF) were synthesized and employed as substrate to construct uric acid biosensors with high sensitivity and selectivity at low working potential. The morphology, microstructures and elemental states of as-prepared samples were investigated by SEM, XRD, TEM and XPS systematically. It was found that a great amount of oxygen vacancies was introduced into the interstitial of CeO₂ and nonstoichiometric CeO₂/C (CeO${}_{2-x}$/C) nanorods based on Ce-MOF were formed under calcination in Ar atmosphere. The increased oxygen vacancies enabled the negatively shifting of the working potential towards H₂O₂ detection for CeO${}_{2-x}$/C nanorods, favoring the construction of biosensors based on the detection of H₂O₂. Uric biosensors based on CeO${}_{2-x}$/C NRs exhibited a high sensitivity of 220.0$\mu$A$\cdot$cm${}^{-2}$$\cdot$mM${}^{-1}$ and a linear range from 50$\mu$M to 1000$\mu$M at working potential of $-$0.4V versus SCE. It also exhibited superior selectivity toward interferents coexisting with uric acid in urine due to the low working potential.

In this work, a sensor for quantitative detection of uric acid (UA) is successfully prepared by electrodepositing Nickel–Copper (Ni–Cu) alloy nanoparticles on poly (3,4-ethyldioxythiophene) modified nitrogen-containing grapheme (Ni–Cu/PEDOT/NGE). The anchoring of PEDOT and Cu–Ni alloy nanoparticles on NGE not only prevents the agglomeration of NGE, but also improves the catalytic activity of the composites. Ni–Cu/PEDOT/NGE shows high electrochemical performance to UA and the oxidation of UA on its interface was an action with two protons and two electrons. Under the optimized condition, the response current of the sensor is linear with UA concentration within the range of 0.1–10$\mu$M and 10–50$\mu$M. A low detection limit of 0.059$\mu$M at S/$\mathrm{\text{N}}=3$ is obtained. Additionally, the fabricated electrochemical sensor with good sensitivity and selectivity to UA may be promising for practical clinical testing.

A simple pyrolysis, activation and hydrothermal method was utilized to synthesize composite materials (Fe₃O₄/SFP) of ferroferric oxide and nitrogen self-doped sunflower plate-derived carbon for the simultaneous electrochemical sensing of ascorbic acid (AA), dopamine (DA) and uric acid (UA). The Fe₃O₄/SFP had synergistic catalytic effect on target molecules, and the oxidation peak potential of AA, DA and UA was well distinguished in the differential pulse voltammetry determination. Under the optimal conditions, the linear response ranges of AA, DA and UA are 3–150$\mu$M, 5–450$\mu$M and 15–1200$\mu$M, respectively. The detection limits of AA, DA and UA ($S$/$N=3$) are 1.0$\mu$M, 0.4$\mu$M and 1.48$\mu$M, respectively, and the sensitivity is 1.87$\mu \mathrm{\text{A}}\cdot \mu {\mathrm{\text{M}}}^{-1}\cdot {\mathrm{\text{cm}}}^{-2}$ (3–20$\mu$M) and 0.64$\mu \mathrm{\text{A}}\cdot \mu {\mathrm{\text{M}}}^{-1}\cdot {\mathrm{\text{cm}}}^{-2}$ (20–150$\mu$M) for AA, 3.90$\mu \mathrm{\text{A}}\cdot \mu {\mathrm{\text{M}}}^{-1}\cdot {\mathrm{\text{cm}}}^{-2}$ (5–20$\mu$M) and 1.21$\mu \mathrm{\text{A}}\cdot \mu {\mathrm{\text{M}}}^{-1}\cdot {\mathrm{\text{cm}}}^{-2}$ (20–450$\mu$M) for DA and 1.12$\mu \mathrm{\text{A}}\cdot \mu {\mathrm{\text{M}}}^{-1}\cdot {\mathrm{\text{cm}}}^{-2}$ (15–100$\mu$M) and 0.31$\mu \mathrm{\text{A}}\cdot \mu {\mathrm{\text{M}}}^{-1}\cdot {\mathrm{\text{cm}}}^{-2}$ (100–1200$\mu$M) for UA. In addition, satisfactory results have been obtained for the determination of AA, DA and UA in normal human serum, which provides a new research direction for the construction of electrochemical sensors in the future.

Living organisms evolved by exploiting molybdenum as a catalyst, incorporating it in the active site of oxidoreductase enzymes that control a diverse array of oxygen, hydrogen and sulfur atom transfer reactions. The chemical versatility of this successful partnership, protein–molybdenum, enables the fulfillment of distinct physiological roles, from bacterial atmospheric dinitrogen and carbon dioxide fixation to human sulfite detoxification. After several decades of research, our present comprehensive understanding of the structure and function of molybdoenzymes renders this an opportune time to draw attention to the largely disregarded biological molybdenum reactivity and bring to light its biotechnological potential and health-related challenges. In this chapter, we provide a concise overview of the molybdoenzymes catalytic features, followed by an outline of selected biotechnological applications to tackle some of the challenges that our modern society faces in the fields of environment, agriculture, climate and energy, namely, nitrate remediation, dinitrogen fixation and carbon dioxide capture and utilization. A brief account of molybdenum’s human health implications is also included to highlight the relevance of these metalloenzymes to medicine and the pharma industry.

The formation of kidney stones was related closely to the properties of urinary crystallites. This study aims to investigate the components of urinary crystallites in 109 cases of patients with uric acid (UA) stones using High-Resolution Transmission Electron Microscopy (HRTEM). Urinary crystallites in patients with UA stones, that contain calcium oxalate monohydrate, calcium phosphate, and ammonium urate crystals, were detected and confirmed by X-ray Diffraction (XRD) and Fast Fourier transformation (FFT) in HRTEM, even in small quantities, showing the presence of high UA concentration and low pH in urine.