Antioxidative phytochemicals from Rhododendron oldhamii Maxim. leaf extracts reduce serum uric acid levels in potassium oxonate-induced hyperuricemic mice. Issue 1 (December 2015)

• Record Type: Journal Article
• Authors: Tung, Yu-Tang; Lin, Lei-Chen; Liu, Ya-Ling; Ho, Shang-Tse; Lin, Chi-Yang; Chuang, Hsiao-Li; Chiu, Chien-Chao; Huang, Chi-Chang; Wu, Jyh-Horng
• Is Part Of: BMC complementary and alternative medicine. Volume 15:Issue 1(2015)
• Page Start: 1
• Page End: 10
• Publication Date: 2015-12
• Subjects: Rhododendron oldhamii maxim -- Leaf -- Phytochemical -- Online HPLC–DPPH -- Hyperuricemia; Alternative medicine -- Periodicals; Complementary Therapies -- Periodicals; 615.505
• DOI: 10.1186/s12906-015-0950-7
• Languages: English
• ISSNs: 1472-6882

Abstract

Abstract Background Some of the genusRhododendron was used in traditional medicine for arthritis, acute and chronic bronchitis, asthma, pain, inflammation, rheumatism, hypertension and metabolic diseases and many species of the genusRhododendron contain a large number of phenolic compounds and antioxidant properties that could be developed into pharmaceutical products. Methods In this study, the antioxidative phytochemicals ofRhododendron oldhamii Maxim. leaves were detected by an online HPLC–DPPH method. In addition, the anti-hyperuricemic effect of the active phytochemicals fromR. oldhamii leaf extracts was investigated using potassium oxonate (PO)-induced acute hyperuricemia. Results Six phytochemicals, including (2R, 3R )-epicatechin (1 ), (2R, 3R )-taxifolin (2 ), (2R, 3R )-astilbin (3 ), hyposide (4 ), guaijaverin (5 ), and quercitrin (6 ), were isolated using the developed screening method. Of these, compounds3, 4, 5, and6 were found to be major bioactive phytochemicals, and their contents were determined to be 130.8 ± 10.9, 105.5 ± 8.5, 104.1 ± 4.7, and 108.6 ± 4.0 mg per gram of EtOAc fraction, respectively. In addition, the four major bioactive phytochemicals at the same dosage (100 mmol/kg) were administered to the abdominal cavity of potassium oxonate (PO)-induced hyperuricemic mice, and the serum uric acid level was measured after 3 h of administration. H&E staining showed that PO-induced kidney injury caused renal tubular epithelium nuclear condensation in the cortex areas or the appearance of numerous hyaline casts in the medulla areas; treatment with 100 mmol/kg of EtOAc fraction, (2R, 3R )-astilbin, hyposide, guaijaverin, and quercitrin significantly reduced kidney injury. In addition, the serum uric acid level was significantly suppressed by 54.1, 35.1, 56.3, 56.3, and 53.2 %, respectively, by the administrations of 100 mmol/kg EtOAc fraction and the derived major phytochemicals, (2R, 3R )-astilbin, hyposide, guaijaverin, and quercitrin, compared to the PO group. The administration of 10 mg/kg benzbromarone, a well-known uricosuric agent, significantly reduced the serum uric acid level by 45.5 % compared to the PO group. Conclusion The in vivo decrease in uric acid was consistent with free radical scavenging activity, indicating that the major phytochemicals ofR. oldhamii leave extracts and the derived phytochemicals possess potent hypouricemic effects, and they could be potential candidates for new hypouricemic agents.