Study on the correlation between constituents detected in serum from Rhizoma Smilacis Glabrae and the reduction of uric acid levels in hyperuricemia

Enhancement of oral bioavailability and anti-hyperuricemic activity of aloe emodin via novel Soluplus®-glycyrrhizic acid mixed micelle system

The objective of this study was to fabricate a novel drug delivery system using Soluplus® (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer) and glycyrrhizic acid to improve solubility, bioavailability, and anti-hyperuricemic activity of aloe emodin (AE). The AE-loaded mixed micelles (AE-M) were prepared by thin-film hydration method. The optimal AE-M contained small-sized (30.13 ± 1.34 nm) particles with high encapsulation efficiency (m/m, %) of 90.3 ± 1.08%. The release rate of AE increased in the micellar formulation than that of free AE in the four media (DDW, pH 7.0; phosphate buffer solution, pH 7.4; phosphate buffer solution, pH 6.8; and hydrochloric acid aqueous solution, pH 1.2). In comparison to free AE, the pharmacokinetic study of AE-M showed that its relative oral bioavailability increased by 3.09 times, indicating that mixed micelles may promote gastrointestinal absorption. More importantly, AE-M effectively reduced uric acid level by inhibiting xanthine oxidase (XOD) activity in model rats. The degree of ankle swelling, serum levels of interleukin (IL)-1, and IL-6-related inflammatory factors levels all decreased in the gouty arthritis model established via monosodium urate (MSU) crystals. Taken together, the AE-M demonstrated the potential to improve the bioavailability, anti-hyperuricemic activity, and anti-inflammation of AE.

Natural Xanthine Oxidase Inhibitor 5-O-Caffeoylshikimic Acid Ameliorates Kidney Injury Caused by Hyperuricemia in Mice

Xanthine oxidase (XOD) inhibition has long been considered an effective anti-hyperuricemia strategy. To identify effective natural XOD inhibitors with little side effects, we performed a XOD inhibitory assay-coupled isolation of compounds from Smilacis Glabrae Rhizoma (SGR), a traditional Chinese medicine frequently prescribed as anti-hyperuricemia agent for centuries. Through the in vitro XOD inhibitory assay, we obtained a novel XOD inhibitor, 5-O-caffeoylshikimic acid (#1, 5OCSA) with IC₅₀ of 13.96 μM, as well as two known XOD inhibitors, quercetin (#3) and astilbin (#6). Meanwhile, we performed in silico molecular docking and found 5OCSA could interact with the active sites of XOD (PDB ID: 3NVY) with a binding energy of −8.6 kcal/mol, suggesting 5OCSA inhibits XOD by binding with its active site. To evaluate the in vivo effects on XOD, we generated a hyperuricemia mice model by intraperitoneal injection of potassium oxonate (300 mg/kg) and oral gavage of hypoxanthine (500 mg/kg) for 7 days. 5OCSA could inhibit both hepatic and serum XOD in vivo, together with an improvement of histological and multiple serological parameters in kidney injury and HUA. Collectively, our results suggested that 5OCSA may be developed into a safe and effective XOD inhibitor based on in vitro, in silico and in vivo evidence.

A brief review of urate transporter 1 (URAT1) inhibitors for the treatment of hyperuricemia and gout: Current therapeutic options and potential applications

Hyperuricemia is a common metabolic condition, cause by increased levels of serum urate (SUA). Reduced excretion of uric acid is reported as the key factor of primary hyperuricemia, accounting for approximately 90% of the cases. Urate transporter 1 (URAT1) is a major protein involved in uric acid reabsorption (about 90%). Therefore, URAT1 inhibitors are considered to be a highly effective and promising class of uricosuric agents for treating hyperuricemia. This review summarizes the development of URAT1 inhibitors for the treatment of hyperuricemia, including approved URAT1 inhibitors, URAT1 inhibitors under development in clinical trials, substances with URAT1 inhibitory effects from derivatives and natural products, and conventional drugs with new uses. This review provides new ideas regarding research on URAT1 inhibitors by introducing the structure, properties, and side effects of chemical drugs, as well as the sources and categories of natural drugs. We also discuss new mechanisms of classic drugs, which may provide guidance to many practicing clinicians. The research and discovery of new inhibitors remain in full swing, and tremendous developments are expected in the field.

The Efficacy and Mechanism of Chinese Herbal Medicines in Lowering Serum Uric Acid Levels: A Systematic Review

Background. Chinese herbal medicines are widely used to lower serum uric acid levels. However, no systemic review summarizes and evaluates their efficacies and the underlying mechanisms of action. Objectives. To evaluate the clinical and experimental evidences for the effectiveness and the potential mechanism of Chinese herbal medicines in lowering serum uric acid levels. Methods. Four electronic databases PubMed, Wed of Science, the Cochrane Library and Embase were used to search for Chinese herbal medicines for their effects in lowering serum uric acid levels, dated from 1 January 2009 to 19 August 2020. For clinical trials, randomized controlled trials (RCTs) were included; and for experimental studies, original articles were included. The methodological quality of RCTs was assessed according to the Cochrane criteria. For clinical trials, a meta-analysis of continuous variables was used to obtain pooled effects. For experimental studies, lists were used to summarize and integrate the mechanisms involved. Results. A total of 10 clinical trials and 184 experimental studies were included. Current data showed that Chinese herbal medicines have promising clinical efficacies in patients with elevated serum uric acid levels (SMD: −1.65, 95% CI: −3.09 to −0.22; p = 0.024). There was no significant difference in serum uric acid levels between Chinese herbal medicine treatments and Western medicine treatments (SMD: −0.13, 95% CI: −0.99 to 0.74; p = 0.772). Experimental studies revealed that the mechanistic signaling pathways involved in the serum uric acid lowering effects include uric acid synthesis, uric acid transport, inflammation, renal fibrosis and oxidative stress. Conclusions. The clinical studies indicate that Chinese herbal medicines lower serum uric acid levels. Further studies with sophisticated research design can further demonstrate the efficacy and safety of these Chinese herbal medicines in lowering serum uric acid levels and reveal a comprehensive picture of the underlying mechanisms of action.

Discovery of the active compounds of Smilacis Glabrae Rhizoma by utilizing the relationship between the individual differences in blood drug concentration and the pharmacological effect in rats

ETHNOPHARMACOLOGICAL RELEVANCE

This study addresses the rapid discovery of the active compounds (the original constituents and/or metabolites) of a traditional Chinese drug, Smilacis Glabrae Rhizoma (SGR).

AIM OF THE STUDY

The aim of this study was to develop a new method to find out the active compounds of traditional drugs in vivo.

MATERIALS AND METHODS

A method was established to discover and identify the potential active compounds in drug-containing plasma from rats that were orally administered SGR extract, utilizing the relationship between the individual differences in blood drug concentrations in the rats and the resulting differences in pharmacological effect, and the method was denoted as the RID-PE method. For this method, we used high-performance liquid chromatography with a diode array detector combined with electrospray ionization ion trap time-of-flight multistage mass spectrometry (LC-MSⁿ) to identify the compounds (the original constituents and metabolites) and to determine the peak areas of the compounds in drug-containing plasma following SGR treatment. The anti-inflammatory effect of SGR was evaluated using a carrageenan-induced inflammatory rat model. According to the percent inhibition of paw edema in each model rat (14 rats total) orally administered SGR extract, the plasma samples from the rats were sorted and divided into 7 groups. Each group consisted of two plasma samples, and their percent inhibition of paw edema were similar to each other. We performed an LC-MSⁿ analysis on 3 plasma groups, which showed large differences in the inhibition rates, with percent inhibitions of 92.7%, 72.4% and 38.4%. The correlation coefficients (r) between the peak area of each compound and the pharmacological effect (inhibition ratio) of SGR in the three groups were analyzed using SPSS software. When the correlation coefficients of the compounds are greater than 0.8 (0.8 < r ≤1), these compounds are strongly and positively correlated with anti-inflammatory activity, making them potential anti-inflammatory active compounds.

RESULTS

Fifty-eight potential anti-inflammatory compounds (0.8 < r ≤ 1) from SGR were discovered in model rat plasma using the RID-PE method, 47 of which were considered to be new potentially anti-inflammatory compounds. Among these compounds, four original constituents and 5 isomers of potential anti-inflammatory metabolites were validated to have significant anti-inflammatory effects, and they included astilbin, syringic acid, catechin, coumalic acid, resveratrol-3'-O-glucuronide (RG, isomer of M2 or M3), 3'-O-methyl-(+)-epicatechin-4'-O-glucuronide (CA-1, isomer of M16), 4'-O-methyl-(+)-epicatechin-3'-O-glucuronide (CA-2, isomer of M16), 4'-O-methyl-(+)-epicatechin-7-O-glucuronide (CA-3, isomer of M16) and 3'-O-methyl-(+)-epicatechin-7-O-glucuronide (CA-4, isomer of M16). In addition, four isomers (CA-1-CA-4) were reported to have anti-inflammatory effects for the first time, and CA-3 was a new compound.

CONCLUSIONS

The RID-PE method can be used to discover and identify the active constituents and metabolites of SGR systematically and in vivo. Furthermore, these findings enhance our understanding of the metabolism and effective forms of SGR.

ASTILBIN: A PROMISING UNEXPLORED COMPOUND WITH MULTIDIMENSIONAL MEDICINAL AND HEALTH BENEFITS

BACKGROUND

Many flavonoids have various beneficial actions like anti-inflammatory, anti-carcinogenic properties and many other clinical conditions. Astilbin is one such flavanoid compound having many physiological as well as pharmacological actions.

PURPOSE

To summarize the important findings from the research conducted using astilbin having significance to its physiological and pharmacological activities as well as the patents filed using astilbin.

STUDY DESIGN

Systematic review and compilation of the collected literature.

METHOD

An extensive investigation of literature was done using several worldwide electronic scientific databases like PUBMED, SCOPUS, Science Direct and Google Scholar etc. All the article available in the English language that used our compound of interest i.e. astilbin, on the basis of inclusion criteria decided were retrieved from these databases, thoroughly reviewed and were summarized.

RESULT

It has been established that astilbin can play a vital in the management of diseases associated with immune system. It also possesses antibacterial, anti-oxidative and hepatoprotective activity.

CONCLUSION

These researches provide evidence that astilbin possesses great potential and thus can be utilized in the management of various disorders, thus establishing itself as a potential candidate for novel drug development. Also, there is still room for research on astilbin like it can be evaluated for anticancer potential, protective effect in various diabetic complications and many more. Overall observations from data suggested that astilbin is a promising compound and proved its efficacy in every preclinical study which is conducted till date. Some of the pharmacological activity is still unexplored. After successful preclinical trials, astilbin can go for further clinical trials.

Astilbin reduces ROS accumulation and VEGF expression through Nrf2 in psoriasis-like skin disease

Background

Psoriasis is a common and intractable skin disease affecting the physical and mental health of patients. The accumulation of ROS is involved in the pathogenesis of psoriasis and antioxidants are believed to be therapeutic. This study aimed to investigate the therapeutic efficacy of astilbin on ROS accumulation in psoriasis.

Results

The study showed that 50 μg/ml astilbin could inhibit the growth and reduce the accumulation of ROS in HaCaT cells stimulated by IL-17 and TNF-α. Astilbin could elevate the Nrf2 accumulation in the nuclei, eventually leading to the transcriptional activation of various antioxidant proteins and reducing the expression of VEGF.

Conclusions

Our results collectively suggest that astilbin could induce Nrf2 nucleus translocation, which is contribute to reduce the ROS accumulation and VEGF expression, and inhibit the proliferation of HaCaT cells.

Effects of Alismatis Rhizoma and Rhizoma Smilacis Glabrae Decoction on Hyperuricemia in Rats

The combination of Alismatis Rhizoma (AR) and Rhizoma Smilacis Glabrae (RSG), as Chinese herb medicine, has been used for their uric acid-lowering effect. However, the effects and mechanism of the combination of the two medicines have not been fully reported. Therefore, to explore the effects of AR-RSG combination decoction on the treatment of chronic hyperuricemia (HUA) in rats as well as the underlying mechanisms, in this study, at the first stage, a long-term HUA rats model was established by gavage of oteracil potassium plus adenine; allopurinol was used as the positive control, and the uric acid-lowering effects of AR or RSG decoction alone with low and high dose were evaluated, respectively. Serum uric acid (UA) and xanthine oxidase (XOD) were determined mainly, and pathological analysis of the kidney and liver was carried out after sacrifice of the animals. And then, at the second stage, four dose groups of AR-RSG combination treatment were investigated in HUA rats. In addition to the indicators measured at the first stage, the expression of urate anion exchanger 1 (URAT1) in rat kidney was determined by immunohistochemistry. We discovered that the UA levels of the model group in both stages were significantly and steadily higher than those of control groups. AR and RSG alone or in combination possess ability to decrease serum UA level of HUA rats, with effects more marked in the combination groups. The uric acid-lowering mechanism of AR-RSG combination may be related to its inhibiting activity of XOD, improving kidney damage and downregulating the expression of URAT1 in kidney.

Screening the Best Compatibility of Selaginella moellendorffii Prescription on Hyperuricemia and Gouty Arthritis and Its Mechanism

Objectives

The Selaginella moellendorffii prescription (SMP) consists of S. moellendorffii Herba (SM), Smilacis glabrae Rhizoma (SGR), and Plantaginis Semen (PS). It has been commonly used to treat hyperuricemia and acute gouty arthritis as a hospital preparation. This study was aimed at investigating the best compatibility ratio of SMP on hyperuricemia and gouty arthritis and getting better insight of the possible mechanism. Methods. In vitro, anti-inflammatory activity of SMP was evaluated by lipopolysaccharide (LPS) induced RAW264.7 cells. The release of nitric oxide (NO) was screened by Griess assay, and NF-κB p65 and NLRP3 proteins expression was examined by immunofluorescence assay. Then, the levels of creatinine (Cr), blood urea nitrogen (BUN), and uric acid (UA) were detected in mice induced by potassium oxonate, and the paw oedema, inflammatory mediators, and histological examination were analyzed in rats induced by monosodium urate (MSU). HPLC method was employed to investigate the chemical profile of this preparation. Results. In vitro, SMP-3 (the ratio of SMP:SGR:PS was 3:1:1) exhibited the most potent anti-NO production activity without obvious toxicity. This anti-inflammatory effect was associated with suppression of NF-κB p65 nuclear translocation and NLRP3 protein expression. In animal experiments, the levels of BUN and Cr in SMP-3 group were lower than other extract groups, and the level of UA was also remarkably decreased by SMP-3 in hyperuricemic mice (P<0.01). Besides, SMP-3 extract was able to prevent the paw edema, reduce gouty joint inflammatory features, and decrease the levels IL-1β, PGE-2, IL-8, and NO in gouty arthritis rats. Furthermore, 6-C-β-D-xylopyranosyl-8-C-β-D-glucopyranosyl, apigenin, and astilbin were identified from SMP-3 extract.

Conclusions

In summary, SMP-3 may be a potential therapeutic agent for the prevention of hyperuricemic and gout.

Protective effects of Rhizoma smilacis glabrae extracts on potassium oxonate- and monosodium urate-induced hyperuricemia and gout in mice

BACKGROUND

Rhizoma smilacis glabrae (RSG, tufuling) has been widely used in traditional Chinese medicine for deoxidation, dampness relief, and easing joint movement. The chemical composition of RSG has been systematically confirmed, and some of its compounds have been revealed to possess antioxidant, anti-inflammatory, immunomodulatory, hypouricemic, and hepatoprotective effects.

PURPOSE

We aimed to clarify whether a RSG extract attenuates hyperuricemia, paw edema, and renal injury in mice with potassium oxonate (PO)- and monosodium urate (MSU)-induced chronic hyperuricemia and gout.

METHODS

RSG water extract was obtained and analyzed by HPLC-DAD-MS/MS. To establish a murine model with chronic hyperuricemia and gout, PO was orally administered daily from day 0 to day 24, whereas MSU was injected into the tibiotarsal joint on day 21. The mice in the drug intervention groups were treated once daily with doses of allopurinol or RSG extract from day 21 to day 24. The diameter of the ankle joints was measured with calipers. Serum TNF-α and IL-1β concentrations, hepatic XOD activity, and uric acid, creatinine, and blood urea nitrogen (BUN) levels were also determined. The right kidney and articular cavities were fixed, cut into sections, and stained with hematoxylin and eosin.

RESULTS

Nine compounds in the RSG water extract were unambiguously identified as 5-O-caffeoylshikimic acid, neoastilbin, astilbin, taxifolin, neoisoastilbin, isoastilbin, engeletin, isoengeletin, and trans-resveratrol. The RSGE treatment dose-dependently reduced PO- and MSU-induced paw edema, serum TNF-α, IL-1β, IL-6, IL-12, uric acid, and BUN, while significantly elevated serum IL-10, urinary uric acid and creatinine levels as compared with the respective values in the hyperuricemic and gouty mice group (vehicle group). Moreover, the hepatic XOD activity was dose-dependently reduced by the RSGE treatment. In addition, RSGE treatment not only ameliorated the infiltration of inflammatory cells, tubular dilation and vacuole formation in renal tubular, but also improved the synovial hyperplasia, reduced inflammatory cells infiltration into the synovium, and diminished the erosive damage in the cartilage.

CONCLUSION

The murine model with chronic hyperuricemia and gout be built in present study is consistent with the clinical symptoms of patients with long-standing hyperuricemia and acute gouty arthritis. RSG water extract has potent efficacy in ameliorating murine hyperuricemia and gout induced by PO and MSU.

Application of UHPLC/ESI-Q-TOF-MS/MS to Identify Constituents of Erding Granule and Anti-hyperuricemia Effect

Background:

Erding granule (EDG) widely used as an agent with the effect of heat-clearing, detoxifying, eliminating dampness, relieving jaundice and upper respiratory tract disease in clinical application, but the systematic chemical information and anti-hyperuricemia effect of EDG was still unclear.

Methods:

An ultra-high performance liquid chromatography combined with electrospray ionization quadrupole time-of-flight mass spectrometry (UHPLC/ESI-Q-TOF-MS/MS) method was utilized to rapidly identify the chemical constituents of EDG. The anti-hyperuricemia effect of EDG was evaluated based on the effect on xanthine oxidase inhibitory activity (in vitro) and lowering uric acid (in vivo).

Results:

198 compounds were tentatively separated and identified or characterized within 30 min by UHPLC/ESI-Q-TOF MS/MS. These compounds were categorized as 22 coumarins, 38 flavones, 67 alkaloids, 36 organic acids, 16 sesquiterpenes, 14 lignans and 5 the others constituents. Meanwhile, EDG significantly decreases the serum urate level of hyperuricemic mice induced by potassium oxonate, while EDG did not significantly decrease the serum urate level of hyperuricemic mice induced by hypoxanthine and activity of xanthine oxidase in vitro.

Conclusion:

The method developed was rapid and sensitive to characterize the chemical constituents of EDG, and provide a systematic view of chemical information for EDG. Furthermore, we first discovered the anti-hyperuricemia effect of EDG and it would further provide the reference for clarifying the mechanism of EDG on lowering uric acid.

Risk factors analysis for hyperuricemic nephropathy among CKD stages 3-4 patients: an epidemiological study of hyperuricemia in CKD stages 3-4 patients in Ningbo, China

Objective: Uric acid (UA) is a risk marker of CKD and SUA level in CKD 3–4 patients closely correlates with hyperuricemic nephropathy (HN) morbidity. This study was designed to evaluate the risk factors for HN in CKD 3–4 patients.

Methods: The 461 CKD 3–4 patients were recruited and all patients were divided into three groups (24 h UUA normal, underexeret, and overproduct type groups) according to the 24 h UUA level after receiving low purine food for five days. Clinical and biochemical characteristics of CKD patients were collected for the logistic regression analysis. Correlation analysis of the mRNA relative expression level of hUAT and hURAT1 with serum UA (SUA) level also was evaluated.

Results: There were significant increases in characteristics including average age, waist-to-height ratio (WHR), SUA levels, HN ratio, TG/HDL ratio, body mass index (BMI), blood pressure (BP), uNgal/Cr. ratio, and uKim-1/Cr. ratio in overproduct type group in comparison with the other two groups. Logistic regression analysis showed SUA, CHO, uKim-1/Cr. ratio and uNgal/Cr. ratio were independent and multiple risk factors for HN. Moreover, hUAT and hURAT1 mRNA relative expression levels were significantly correlated with SUA level in the underexeret type CKD 3–4 patients.

Conclusions: These results showed SUA and other characteristics contributed to HN morbidity in CKD 3–4 patients.

Hypouricemic Effects of Ganoderma applanatum in Hyperuricemia Mice through OAT1 and GLUT9

Ganoderma applanatum (G. applanatum) dispels wind to eliminate dampness and exhibited nephron- and liver-protective effects as noted in Chinese herbal classic literature; it might also affect hyperuricemia. Therefore, we examined the hypouricemia effects and mechanisms underlying G. applanatum on chemical-induced hyperuricemia in mice. Ethanol (GAE) and water (GAW) extracts were prepared by extracting G. applanatum in ethanol (GAE), followed by bathing the remains in water to yield GAW. GAE and GAW were administered orally at different doses to hyperuricemia mice, while allopurinol and benzbromarone served as positive controls. Both GAE and GAW showed remarkable hypouricemia activities, rendering a substantial decline in the SUA (serum uric acid) level in hyperuricemia control (P < 0.01). Moreover, the urine uric acid (UUA) levels were enhanced by GAE and GAW. In contrast to the evident renal toxicity of allopurinol, GAE and GAW did not show a distinct renal toxicity. Almost no suppressing effect was observed on the XOD activities. However, compared to the hyperuricemia control, OAT1 was elevated remarkably in mice drugged with GAE and GAW, while GLUT9 was significantly decreased. Similar to benzbromarone, GAE decreased the URAT1 protein levels significantly (P < 0.01), while GAW did not display a similar effect. GAE and GAW downregulated the level of CNT2 proteins in the gastrointestinal tract of hyperuricemia mice. Thus, G. applanatum produced outstanding hypouricemic effects, mediated by renal OAT1, GLUT9, and URAT1 and gastrointestinal CNT2 that might elevate urine uric secretions and decline in the absorption of purine in the gastrointestinal tracts. G. applanatum showed little negative influence on inner organs. By docking screening, four top-ranked compounds were identified that necessitated further investigation. Compounds: potassium oxonate, hypoxanthine, allopurinol, benzbromarone.

Traditional Chinese Medicine Formula "Xiaofeng granules" suppressed gouty arthritis animal models and inhibited the proteoglycan degradation on chondrocytes induced by monosodium urate

ETHNOPHARMACOLOGICAL RELEVANCE

Xiaofeng Granules (XF) is a kind of granules prepared by the famous traditional Chinese medicine formula for its efficiency in treating gouty diseases.

AIM OF THE STUDY

We investigated the relevance between XF that made from Modified simiaowan (MSW) as the anti-gouty arthritis drugs and protective mechanisms for cartilage matrix in order to provide the evidence for new drug application.

MATERIALS AND METHODS

In the present study, we evaluated the anti-gouty arthritis activity of XF in rats and rabbits models induced by MSU together with chondrocytes focusing on the link to proteoglycan degradation in vitro studies.

RESULTS

The results demonstrated that XF significantly reduced the swelling rate and attenuated the pathological changes in joints. The XF-containing serum were used medicated serum in cellular experiments. The in vitro data were in accordance with the in vivo results, showing that the constituents in XF-containing serum had obvious inhibitory effects on the activation of pro-inflammatory mediators in chondrocytes. Moreover, XF-containing serum substantially inhibited MSU-induced expression of glycosaminoglycans(GAG) and hydroxyproline(Hyp), and up regulated proteoglycan, which might be associated with the regulation of the balance of MMP-3/TIMP-1and ADAMTS-4/TIMP-3 inchondrocytes.

CONCLUSION

In conclusion, XF that made from MSW showed obvious effects on acute gouty arthritis, which also provided an effective protection on cartilage matrix degradation.

SIRT1 prevents hyperuricemia via the PGC-1α/PPARγ-ABCG2 pathway

Silent information regulator T1 (SIRT1) plays several key roles in the regulation of lipid and glucose homoeostasis. In this study, we investigated the potential role of SIRT1 in hyperuricemia and explored possible mechanisms. Significant hyperuricemia was detected in C57BL/6 mice treated with oxonate and yeast polysaccharide. Resveratrol (RSV), a specific SIRT1 activator, was administered to the mice. SIRT1 suppressed the increased serum uric acid level but up-regulated the expression of urate transporter ATP-binding cassette subfamily G member 2 (ABCG2) in the ileum of hyperuricemic mice. In a human colon carcinoma cell line, SIRT1 promoted ABCG2 production through the deacetylation of peroxisome proliferator-activated receptor (PPAR) γ co-activator 1α (PGC-1α), which then activated the effectors of PPARγ. Interestingly, the SIRT1-induced up-regulation of ABCG2 was significantly inhibited when PGC-1α or PPARγ was blocked by siRNA transfection. Our data demonstrated that SIRT1 and its activator, RSV, have clear anti-hyperuricemia functions in this mouse model. One possible mechanism is the activation of ABCG2 in the ileum through the PGC-1α/PPARγ pathway.

Phytochemicals from Tradescantia albiflora Kunth Extracts Reduce Serum Uric Acid Levels in Oxonate-induced Rats

Background:

Tradescantia albiflora (TA) Kunth (Commelinaceae) has been used for treating gout and hyperuricemia as folklore remedies in Taiwan. Therefore, it is worthwhile to study the effect of TA extracts on lowering uric acid activity. The hypouricemic effects of TA extracts on potassium oxonate (PO)-induced acute hyperuricemia were investigated for the first time.

Materials and Methods:

All treatments at the same volume (1 ml) were orally administered to the abdominal cavity of PO-induced hyperuricemic rats. One milliliter of TA extract in n-hexane (HE), ethyl acetate (EA), n-butanol (BuOH), and water fractions has 0.28, 0.21, 0.28, and 1.03 mg TA, respectively; and the plasma uric acid (P_UA) level was measured for a consecutive 4 h after administration.

Results:

All four fractions' extracts derived from TA were observed to significantly reduce P_UA compared with the PO group. The EA-soluble fraction (TA-EA) exhibited the best xanthine oxidase (XO) inhibitory activity. Following column chromatography, 12 phytochemicals were isolated and identified from the EA fraction. The IC₅₀ values of isolated phytochemicals indicated that bracteanolide A (AR11) showed the remarkable XO inhibitory effect (IC₅₀ value of 76.4 μg/ml). These findings showed that the in vivo hypouricemic effect in hyperuricemic rats was consistent with in vitro XO inhibitory activity, indicating that TA extracts and derived phytochemicals could be potential candidates as hypouricemic agents.

SUMMARY

Tradescantia albiflora extracts possess in vivo hypouricemic action in hyperuricemic rats

T. albiflora extracts exhibited strong inhibitory activity against xanthine oxidase (XO)

Butenolide may play an important role in XO inhibition

The extract bracteanolide A was demonstrated potent XO inhibitory activity in vitro.

Abbreviations used: TA: Tradescantia albiflora, PO: potassium oxonate, HE: n-hexane, EA: ethyl acetate, BuOH: n-butanol, P_UA: plasma uric acid, XO: xanthine oxidase, MeOH: methanol, IP: intraperitoneal

Optimization of astilbin extraction from the rhizome of Smilax glabra, and evaluation of its anti-inflammatory effect and probable underlying mechanism in lipopolysaccharide-induced RAW264.7 macrophages

Astilbin, a dihydroflavonol derivative found in many food and medicine plants, exhibited multiple pharmacological functions. In the present study, the ethanol extraction of astilbin from the rhizome of smilax glabra Roxb was optimized by response surface methodology (RSM) using Box-Behnken design. Results indicated that the obtained experimental data was well fitted to a second-order polynomial equation by using multiple regression analysis, and the optimal extraction conditions were identified as an extraction time of 40 min, ethanol concentration of 60%, temperature of 73.63 °C, and liquid-solid ratio of 29.89 mL/g for the highest predicted yield of astilbin (15.05 mg/g), which was confirmed through validation experiments. In addition, the anti-inflammatory efficiency of astilbin was evaluated in lipopolysaccharide (LPS)-induced RAW 264.7 cells. Results showed that astilbin, at non-cytotoxicity concentrations, significantly suppressed the production of nitric oxide (NO) and tumor necrosis factor-α (TNF-α), as well as the mRNA expression of inducible nitric oxide synthase (iNOS) and TNF-α in LPS-induced RAW 264.7 cells, but did not affect interleukin-6 (IL-6) release or its mRNA expression. These effects may be related to its up-regulation of the phosphorylation of p65, extracellular signal-regulated kinases 1/2 (ERK1/2) and c-Jun N-terminal kinase (JNK).

The effect of resveratrol on the recurrent attacks of gouty arthritis

Gouty arthritis is characterized by inflammation induced by monosodium urate crystal (MSU) deposition, which is resulted by increase of serum urate concentration. The management of gout, especially the recurrent attacks of chronic gouty arthritis, is still a problem to be resolved. In this study, we aimed to develop the preventive and therapeutic effects of resveratrol on gouty arthritis. Monosodium urate crystal (MSU) was used to induce gouty arthritis in foot pad of C57BL/6 mice. Yeast polysaccharide and potassium oxonate were used to induce hyperuricemia in Kunming mice. Resveratrol was intraperitoneally injected to the mice in the treatment group. Article inflammation and serum uric acid level were investigated to estimate the effect of resveratrol in gout. Yeast polysaccharide and potassium oxonate were used to induce hyperuricemia in mice, and MSU to induce gouty arthritis. We identified that resveratrol inhibited foot swelling and inflammation-associated 99mTc uptake in gouty mice. Moreover, serum uric acid level was also decreased by resveratrol in hyperuricemia mice. This study highlighted that resveratrol might be applied to prevent the recurrent attack of gouty arthritis because of its inhibition of articular inflammation and down-regulation of serum uric acid.