Antihyperuricemic effect of mangiferin aglycon derivative J99745 by inhibiting xanthine oxidase activity and urate transporter 1 expression in mice

A mangiferin aglycon derivative J99745 has been identified as a potent xanthine oxidase(XOD) inhibitor by previous in vitro study. This study aimed to evaluate the hypouricemic effects of J99745 in experimental hyperuricemia mice, and explore the underlying mechanisms. Mice were orally administered 600 mg/kg xanthine once daily for 7 days and intraperitoneally injected 250 mg/kg oxonic acid on the 7 th day to induce hyperuricemia. Meanwhile, J99745(3, 10, and 30 mg/kg), allopurinol(20 mg/kg) or benzbromarone(20 mg/kg) were orally administered to mice for 7 days. On the 7 th day,uric acid and creatinine in serum and urine, blood urea nitrogen(BUN), malondialdehyde(MDA) content and XOD activities in serum and liver were determined. Morphological changes in kidney were observed using hematoxylin and eosin(H&E) staining. Hepatic XOD, renal urate transporter 1(URAT1), glucose transporter type 9(GLUT9), organic anion transporter 1(OAT1) and ATP-binding cassette transporter G2(ABCG2) were detected by Western blot and real time polymerase chain reaction(PCR). The results showed that J99745 at doses of 10 and 30 mg/kg significantly reduced serum urate, and enhanced fractional excretion of uric acid(FEUA). H&E staining confirmed that J99745 provided greater nephroprotective effects than allopurinol and benzbromarone. Moreover, serum and hepatic XOD activities and renal URAT1 expression declined in J99745-treated hyperuricemia mice. In consistence with the ability to inhibit XOD, J99745 lowered serum MDA content in hyperuricemia mice. Our resultssuggest that J99745 exerts urate-lowering effect by inhibiting XOD activity and URAT1 expression, thus representing a promising candidate as an anti-hyperuricemia agent.

Endostatin derivative angiogenesis inhibitors

Objective To throw light on the superiority of the anti-angiogenesis activity of endostatin （ES） derivatives by reviewing the recent progress in the field of ES molecular structure modification. Data sources The data used in this article were mainly from PubMed with relevant English articles published from 1971 to May 2008. The search terms were ＂endostatin＂ and ＂angiothesis＂. Study selection Articles involved in the ES molecular structure modification and the original milestone articles were selected. Results A number of ES derivatives were designed and studied to improve its clinical relevance. The modified ES with polyethylene glycol （PEG）, low molecular weight heparin （LMWH） and IgG Fc domain extended the circulation half-life. Meanwhile the recombinant ESs showed more potent anti-tumor activity than native ES in mouse xenografts. Mutated ES also changed its anti-angiogenesis activity. Conclusions The anti-angiogenesis treatment remains a promising tumor therapeutic strategy. New ES derivatives would be a good choice to meet the future challenge on clinical application of ES.