Résumé
OBJECTIVE Licorice is used throughout the world as a traditional herbal remedy. Ac-cording to Chinese traditional medicine licorice alone can be used to treat inflammation.Although there have been some studies investigated the anti-inflammatory ingredients of licorice, but for the potency of flavonoid glycoside and their aglycones on inflammation are not evaluated.This study was designed to assess the contributions of licorice flavonoid glycosides and their aglycons to its anti-inflammatory and hypnotic effects. METHODS For the flavonoid aglycone's enrichment, the extract of licorice (EL) was fermented in submerged culture of the edible fungus Grifola frondosa HB0071 mycelia which can produce β-glucosidase and catalyze the flavonoid glycosides to aglycones.EL and fermented extract of licorice (FEL) were used in this study. The anti-inflammation test was carried out in arachidonic acid (AA)-induced ear edema model and the hypnotic test was performed by using electroencephalogram (EEG)analysis method in normal freely moving SD rats.The chemicals constituents were analyzed by HPLC.RESULTS During fermentation,the falvonoid glycosides of licorice were hydrolyzed by the time process.Along with fermentation time,the concentration of the major flavonoid glycosides,liquiritin and isoliquiritin were decreased obviously, and simultaneously their aglycons, liquiritigenin and isoliquiriti-genin were remarkably increased in FEL.Moreover,the content of another major constituent glycyrrhi-zic acid and glycyrrhetinic acid were not changed after the fermentation. In AA-induced mice ear ede-ma test,after topical application,FEL(effective dose range:5-20 μg·ear-1)showed more potent inhibito-ry activity than EL(effective dose range:25-100 μg·ear-1).On the other hand,oral administration of EL and FEL exhibited the same hypnotic potency and both enhanced the total sleep time including rapid eye movement (REM) sleep and non-REM sleep time. CONCLUSION These results suggested that the enrichment of flavonoid aglycons such as liquiritigenin and isoliquiritigenin enhanced the anti-inflam-matory potency of licorice extract,and this potentiation has nothing to do with glycyrrhizic acid or glycyr-rhetinic acid.In addition,enrichment of flavonoid aglycones did not alter the hypnotic effect of licorice.
Résumé
A mangiferin aglycon derivative J99745 has been identified as a potent xanthine oxidase (XOD) inhibitor by previous 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 7th 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 7th 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 results suggest that J99745 exerts urate-lowering effect by inhibiting XOD activity and URAT1 expression, thus representing a promising candidate as an anti-hyperuricemia agent.
Résumé
Glycosides are the active ingredients (AIs) of many Chinese herbs and have become hot spots along with the findings of their new functions,such as anti-inflammatory,antivirus,enhanced immunity and anti-cancer.It has been found that glycosides exert their effects by converting to aglycons or other AIs in vivo.Therefore,the transformation of glycosides to the corresponding AIs in vitro becomes very important to enhance their bioavailabilities.The microbial transformation has an unparalleled advantage in the transformation of Chinese herbs in vitro for its reaction specificity,less by-products,mild reaction conditions and environmental protection.This paper summarized and prospected researches of glycosides' microbial transformation.