Effect of Aqueous Dennettia Tripetala Baker F. Leaf Extract on Hyperthyroidism in Albino Rats (Rattus Norvegicus Berkenhout)

Abstract

The present study was undertaken to investigate the effect of aqueous Dennettia tripetala G. Baker leaf extract on hyperthyroidism in albino rat (Rattus norvegicus). A total of 72 adult male albino rats were used for the 28 days study. Hyperthyroidism was induced in the rats of groups B – F, orally, at a dose of 600µg/kg Levothyroxine for 14 days and induction of hyperthyroidism was confirmed by analyzing the serum thyroid hormone level. The serum levels of T3, T4, and TSH of the normal animal were 3.33pmol/L, 12.82pmol/L and 2.67mU/L respectively. However, in hyperthyroid rats, the serum levels of T3 and T4 value increased to 5.22pmol/L and 26.38pmol/L respectively, while the serum levels of TSH value decreased to 0.14mU/L. Only hyperthyroid rats with equivalent (5.22pmol/L and 26.38pmol/L) or higher serum levels of T3, T4, and equivalent (0.14mU/L) or lower serum levels of TSH were used. The extract which was obtained by standard method was screened phytochemically. The rats in the normal control (group A) and hyperthyroid control (group B) were given water and food only, while the rats in the standard control (group C) received 1.35mg/kg of Carbimazole by oral intubation. Furthermore, rats in groups D, E and F were administered graded doses (100mg/kg, 250mg/kg and 500mg/kg) of the extract respectively. The body weights of the rats were determined before the commencement of treatment (week 0) and subsequently during the treatment on a weekly (7 days) interval. Blood samples were also obtained from the orbital sinus of each rat during the treatment on a weekly (7 days) interval for the various analyses. Blood sera from the samples were analysed for thyroid hormone levels (Triiodothyronine, T3; Thyroxine, T4; and Thyroid Stimulating Hormone, TSH) and lipid profile (Total cholesterol, TCH; High-Density Lipoprotein Cholesterol, HDL-C; Low-Density Lipoprotein Cholesterol, LDL-C; and Total Triglyceride, TG). In addition, histopathological analysis of the thyroid gland was carried out in the control and treated rats. It was observed that the body weights of the rats did not change significantly in group A (normal control group), while that of the other groups showed a progressive significant (P < 0.05) duration dependent increase from weeks 0 to 4. The extract dosed groups and the standard control group showed no significance difference (P > 0.05) in T3 and TSH levels when compared to the normal control, while the T4 levels of the group dosed with 500mg/kg extract was statistically similar to the standard control group but varied significantly (P < 0.05) when compared to the normal control group. Also, the total cholesterol and triglyceride levels in the extract dosed groups were significantly higher when compared to the normal and hyperthyroid control groups but significantly lower when compared to the standard control group, while the HDL-C levels in the extract dosed groups and standard control group showed no significant difference (P > 0.05) when compared to the normal control group. The histopathological examination of the thyroid gland showed no remarkable histologic differences in normal control, standard control and extract dosed groups. Results, therefore, showed that the aqueous Dennettia tripetala leaf extract has the potential to overcome hyperthyroidism in albino rat.