Prophylactic effects of Orthosiphon stamineus Benth. extracts on experimental induction of calcium oxalate nephrolithiasis in rats

Ethnopharmacological relevance: Orthosiphon stamineus (OS) popularly known as "diuretic agent" are traditionally used in folk medicine in the treatment of hyperuricemia, rheumatism, gout, nephritis, nephrolithiasis, urethritis and cystitis. Aim of the study: To evaluate prophylactic potentials of total flavonoids, total phenolics and polysaccharides from OS on experimental induction of calcium oxalate (CaOx) nephrolithiasis in rats. Materials and methods: Nephrolithic rats were induced by treating with 1.0% ethylene glycol and 1.0% ammonium chloride for 7 days. Rats in the treated groups were also given OS extracts at the doses of 80 mg/kg and 160 mg/kg. Urine samples (4 h) and serum samples were collected at 7th day for biochemical analysis. Kidney tissues were stained with H.E. and analyzed by light microscopy. Expressions of OPN protein were detected by immunohistochemistry. Rates of nucleation and aggregation of calcium oxalate crystals were derived from 20-min time-course measurements of optic density at 620 nm after mixing solutions containing calcium chloride, sodium oxalate and OS extracts at 37 degrees C, pH 5.7. Results: Polysaccharides exhibited the most significant prophylactic effects by reversing BUN and S-cr levels, ameliorating histopathological changes, increasing urine C2O42- and Ca2+ excretion and downregulating OPN protein expression of kidney in the model rats in comparison with those effects of total flavonoids and total phenolics. Polysaccharides could also significantly inhibit both nucleation and aggregation of CaOx crystals. Conclusions: Polysaccharides were the main therapeutic materials in OS. It had impressive prophylactic effects on CaOx stones in nephrolithic rats, playing a role as a regulator of OPN protein expression to increase urine C2O42- and Ca2+ excretion and also as an inhibitor of CaOx crystallization. (C) 2012 Elsevier Ireland Ltd. All rights reserved.