Gout occurs in individuals who have high serum uric acid levels, in response to precipitation of monosodium urate monohydrate crystals in various tissues, followed by an inflammatory response. 1) The essence of the prevention and treatment of gout is antihyperuricemic therapy, either by uricosuric drugs or by xanthine oxidase (XOD) inhibitors. Allopurinol, an XOD inhibitor which is structurally related to xanthine, binds tightly to the active site of XOD thus causes inhibition on XOD. Allopurinol is used to treat gout for more than 40 years and remains a cornerstone in the therapy of primary and secondary hyperuricemia. 2-7) However, the most common adverse effects of allopurinol are gastrointestinal distress, hypersensitivity reactions, 8) and renal toxicity. 9) Thus, new alternatives with an increased therapeutic activity and less side effects are desired.Dietary flavonoids have been attracted attention because of their potential beneficial effects on human health. The structural components common to these molecules include two benzene rings on either side of a 3-carbon ring (Table 1). 10) Multiple combinations of hydroxyl groups, sugars, oxygens, and methyl groups attached to these structures create the various classes of flavonoids: flavanols, flavanones, flavones, flavanonol, flavan-3-ols (catechins), anthocyanins, and isoflavones. 11) Flavonoids are well known to possess antiviral, antiallergic, antiplatelet, antiinflammatory, antitumor and antioxidant activities. 12-15) Catechin and its derivatives, oligomeric proanthocyanidins, quercetin and quercetin chalcone, Ginkgo flavone glycosides, silymarin, and others can be utilized in preventative and treatment protocols for cardiovascular disease, cancer, inflammatory conditions, asthma, periodontal disease, liver disease, cataracts and macular degeneration. 16,17) Hyperuricemia is a risk factor for the disorder metabolic syndrome and increased cardiovascular disease, and the mechanisms involve inflammation and generation of oxidative stress in the vasculature. 18) Thus, the antiinflammatory and antioxidant activities of flavonoids might bring benefit for hyperuricemia and its complications. In addition, the flavonoids have increasingly aroused interest recently for their hypouricemic action in hyperuricemic animal models. [19][20][21] In the present study, we have explored hypouricemic actions from 15 flavonoids including quercetin, morin, myricetin, kaempferol, icariin, apigenin, luteolin, baicalin, silibinin, naringenin, formonoetin, genistein, puerarin, daidzin and naringin dihydrochalcone in a hyperuricemic animal model induced by potassium oxonate. We have also studied the effects of six most active compounds on serum and liver uric acid levels in normal mice. The effects on liver XOD activities were further examined in animals. MATERIALS AND METHODSMaterials Quercetin, morin, myricetin, kaempferol, icariin, apigenin, luteolin, baicalin, silibinin, naringenin, formonoetin, genistein, puerarin, daidzin and naringin dihydrochalcone were obtained commerci...

A microwave assisted extraction (MAE) procedure was first developed for the simultaneous determination of isoflavonoids and astragalosides in Radix Astragali (RA). MAE showed the highest extraction efficiency when compared to Soxhlet, reflux, and ultrasonic extraction. It was found that flavonoid glycoside malonates were converted into their related glycosides during the prolonged conventional extraction, thus affecting the reproducibility. However, the conversion was inhibited when using MAE. After being optimized in terms of solvents, microwave power, and irradiation time, MAE was used for the simultaneous determination of isoflavonoids and astragalosides in RA with HPLC-UV-evaporative light scattering detection (ELSD). Our results indicated that extraction by MAE was more effective than by other conventional techniques. Moreover, the MAE method followed by HPLC-UV-ELSD determination was a simple, rapid, and reliable method for the quality assessment of RA.

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Fructus Psoraleae, a widely used traditional Chinese medicine, is well known as a health supplement ingredient. In our study, an improved and comprehensive HPLC fingerprint of Fructus Psoraleae was established. Two important new benzofuran glycosides, psoralenoside and isopsoralenoside, were identified as characteristic constituents for the first time. HPLC separation was performed on an RP-C8 column. The mobile phase was acetonitrile and 0.1% acetic acid solution with linear gradient change of acetonitrile from 10 to 82% in 40 min. The flow rate was 1.0 mL/min, and the detection wavelength was set at 310 nm. The HPLC chromatograms of twenty-six samples from different regions of China showed a similar pattern. Twelve peaks were selected as characteristic peaks and further identified as psoralenoside, isopsoralenoside, psoralen, isopsoralen, bavachromene, corylifolin, corylin, psoralidin, isobavachalcone, bavachinin, corylifol A, and bakuchiol, respectively. Nine of them were simultaneously quantitatively analyzed for the first time. A more comprehensive analytical method was established for the fingerprint of Fructus Psoraleae. It is very useful for authentication and quality assessment of the crude drug.