Luteolin-rich chrysanthemum flower extract suppresses baseline serum uric acid in Japanese subjects with mild hyperuricemia

Background: Luteolin is a flavonoid found in various edible plants that exhibits diverse health benefits, including anti-inflammatory and anti-gout effects. However, there has been little clinical investigation of luteolin from the viewpoint of gout prevention. We conducted a clinical trial of supplementation with chrysanthemum flower extract rich in luteolin (LCE) to assess the effect on serum uric acid levels in Japanese men. Methods: We examined the effect of LCE containing 10% luteolin in two double-blind placebo-controlled studies. In the single-dose study, fasting subjects took a capsule containing 100 mg of LCE (10 mg of luteolin) or placebo before ingestion of a high purine base test meal and the serum uric acid level was determined over time. For the repeated-administration study, the subjects ingested placebo or LCE capsule for 4 weeks. Fasting serum uric acid was evaluated before and after ingestion. Results: Oral intake of LCE had no significant influence on serum uric acid. After 4 weeks of LCE ingestion, serum uric acid tended to decrease in the LCE group. A significant decrease of serum uric acid was observed after LCE ingestion in the subjects with a baseline uric acid level of 5.5 to 7.0 mg/dL. There were no abnormalities suggesting adverse effects during or after ingestion of LCE. Conclusion: Ingestion of LCE for 4 weeks reduced the serum uric acid level. Luteolin may be able to prevent gout by controlling uric acid. Abbreviations: XOD: xanthine oxidase; LCE: luteolin-rich chrysanthemum flower extract; CRP: C-reactive protein; AUC: area under the concentration vs. time curve; CFO: chrysanthemum flower oil