Hypouricemic Effect of Submerged Culture of Ganoderma lucidum in Potassium Oxonate-Induced Hyperuricemic Rats

Hyperuricemia is a disease caused by a high level of uric acid in the blood. It is an important factor for gout and may be linked to renal and hepatic failure. The objective of this study was to investigate the hypouricemic effects of submerged culture of Ganoderma lucidum. The lyophilized powder of mycelium (GM) and extracellular polysaccharides (GP) of the G. lucidum submerged culture were prepared. The contents of hypouricemic components, including phenolics and flavonoids, in GM (34.33 +/- 0.41 mg/g and 0.32 +/- 0.01 mg/g) were higher than that in GP (20.52 +/- 1.49 mg/g and not detected). The hypouricemic effect of GM and GP was evaluated in potassium oxonate (PO)-injected rats. The average food intake (23.3 +/- 1.2 g/day) and body weight (355.7 +/- 28.0 g) were decreased, and the serum level of uric acid (5.56 +/- 0.41 mg/dL) was increased in PO-injected rats. However, allopurinol (10 mg/kg b.w.) or GM treatment (200 or 400 mg/kg b.w) improved food intake (26.3 +/- 2.7 g /day) and reduced the level of uric acid (4.45 +/- 0.46 mg/dL). In parallel, the activity of hepatic xanthine oxidase (XOD) was downregulated from 841.29 +/- 299.58 mu U/mg protein to 540.80 +/- 199.20 mu U/mg protein. Moreover, GM and GP (200 or 400 mg/kg b.w) alleviated the level of blood urea nitrogen (BUN) from 30.49 +/- 4.71 to 21.16 +/- 4.25 mg/dL. GP treatment also diminished the level of alanine transaminase (ALT) from 52.63 +/- 18.82 to 27.35 +/- 6.82 U/L. These results clearly demonstrated the hypouricemic effect of submerged G. lucidum culture and their potential against hyperuricemia-associated renal and hepatic damage. GM was more potent to alleviate hyperuricemia, and GP was more potent to improve renal and hepatic function.