Hypoglycemic, hypolipidemic and biochemical effects of tithonia diversifolia aqueous root extract in western diet fed wistar albino rats

Abstract

Background: Diabetes and obesity pose risks of severe complications, including cardiovascular diseases and cancer. The Luo community in Kenya uses Tithonia diversifolia root preparations for hypoglycemic and hypolipidemic effects, necessitating scientific validation. Objectives: To determine the hypoglycemic and hypolipidemic effects of aqueous root extract of Tithonia diversifolia and its biochemical effects on the liver and kidney of western diet-fed Wistar albino rats. Methods: This was a laboratory-based study in wistar albino rats with elevated fasting blood glucose and lipids. The rats were put on a western diet composed of rodent chow enriched with 21% animal lard and 0.15% cholesterol for 35days. Thirty-five male rats weighing 180-200g were selected, acclimatized for one week, and randomly grouped into 7 groups of normal control(G1), those fed on western diet for 35 days(G2), the ones fed on western diet for 35days and given 10mg/kg atorvastatin in the last 7 days(G3), those fed on western diet for 35days and given 0.5mg/kg glibenclamide in the last 7 days(G4), the ones fed on western diet for 35days and given 200mg/kg(G5), and 400mg/kg of the extract (G6) respectively in the last 7 days and the ones fed on western diet for 28 days and reverted to normal diet in the last seven days(G7). Blood fasting glucose levels were determined weekly by obtaining blood from the tail. In contrast, lipid profile, kidney and liver function were determined using blood obtained by cardiac puncture at the end of the experiment. Data was stored in SPSS version 20 and analyzed for means, post-hoc Least Significance Difference, and Duncan's tests to compare the pairs of groups. A p-value ≤ 0.05 was considered statistically significant. Result: The fasting blood glucose levels gradually increased in all the groups between weeks one to four though maintained normal range for wistar albino rats (3.95±1.31 mmol/L). There was a significant reduction (p=0.000) in serum cholesterol (normal 1.06-3.25mmol/L) when the negative control group(G2) was compared to the groups that received 200mg/kg(G5) mean 2.0mmol/L, 400mg/kg of the extract(G6) mean1.2mmol/L and 10mg/kg Atorvastatin(G3) mean 2.0mmol/L. For triglycerides (0.5-2.9mmol/L) p=0.036 the mean values in G5, G6 and G3 were 1.0, 1.0 and 0.4mmol/L respectively. There was a significant increase (p=0.000) in urea levels (normal levels 3.9-8.9mmol/L) and a significant reduction (p=0.011) in creatinine (17.68-61.88umol/L) among groups given 200mg/kg and 400mg/kg extract compared to positive control. There was no significant increase in levels of aspartate aminotransferase (p=0.264) and alanine aminotransferase (p=0.264), whose normal levels are 34-109U/L and 198.68 ±15.66U/L respectively, but there was significant (p=0.000) difference in alkaline phosphatase(95-611U/L) after administration of 200mg/kg of extract daily for seven days. Reverting to rodent chow for seven days(G7) did not significantly change all the parameters except creatinine and urea, where the changes were significant compared to the positive control group. Conclusion: Aqueous root extract of Tithonia diversifolia administered at 200mg/kg and 400mg/kg is safe for the liver and demonstrated hypoglycemic and hypolipidemic activity similar to standard drugs glibenclamide and atorvastatin, respectively. However, it seems to be associated with glomerular damage, as evidenced by the elevated levels of urea. Recommendation: Further studies are recommended in order to establish proper dosage and kidney toxicity.