Abstract:
Introduction: Costus speciosus (CS) plant (Thebu’ in sinhala), is popular among
Sri Lankans as an antidiabetic agent and many of its pharmacological properties have
scientifically proved. This study was designed to investigate the effects of long-term CS leaf
aqueous extract (cslwex) therapy on, liver and kidney of healthy and insulin-resistanceinduced
(IR) Wistar rats. Methods: CS fresh leaf powder(400 g) was refluxed in distilled
water(2L) at 50°C for 6 hours. Excess water was removed under the reduced pressure at
6o°C followed by freeze drying, until a constant weight of cslwex was obtained. Wistar
rats (170-250 g) were divided into 9 groups (n=5 each) and labled A-I. IR was induced in
groups D-I by feeding a modified high-fat-diet for three months. Cslwex oral treatment
was conducted daily for 12 weeks as follows. Group A-Distilled water 1 mL, Group B-1500
mg/kg, Group C-3000 mg/kg, Group D-Distilled water 1 mL, Group E-1500 mg/kg, Group
F-2000 mg/kg, Group G-2500 mg/kg, Group H-3000 mg/kg CSlwex, Group I-Pioglitazone
20 mg/kg. At the end, serum was analysed for ALT,AST and Creatinine. Histopathology of
liver and kidney were observed for toxicity due to cslwex. Results: No significant increase
in ALT or AST were found in IR rats, compared to IR controls (ALT-34.77±6.i9lU/L,
p=0.304; AST-137.55i9.83 IU/L, p=o.928). Also, cslwex did not change ALT and AST of
healthy rats. Serum creatinine of either IR or healthy rats were not increased than their
controls (IR-34.53 ± 1.38 pmol/L; healthy -42.56 ± 3.2738 pmol/L). No features of liver
or renal toxicity were observed histopathologically, in any dose of cslwex treated IR or
healthy rats. Conclusion: In conclusion, 1500-3000 mg/kg doses of Cslwex did not
initiate hepatic or renal toxicity even at 12 weeks continuous therapy. Hence these higher
doses could be used safely in long-term and justifies the possibility of use in day-today life
as well as a remedy in traditional medicine for the proved pharmacological effects.
