Comparative analysis of the antithyroid activity of Annona squamosa and Tetracarpidium conophorum leaf extracts in in-vitro and animal model of hyperthyroidism.

Annona squamosa and Tetracarpidium conophorum are medicinal plants that are traditionally used to treat hyperthyroidism. This study comparatively investigated the antithyroid activities of methanol leaf extracts of A. squamosa and T. conophorum in in-vitro and animal model of hyperthyroidism. The phytochemical constituents and total phenolic contents of both extracts were determined. The effective inhibitory concentrations (IC₅₀) of both extracts on thyroid peroxidase enzyme activity and DPPH radical were determined. In vivo hyperthyroidism was induced with 600 ug/kg L-thyroxin for 12 days and the effect of both extracts on thyroid stimulating hormone (TSH), serum thyroid hormones (T3, T4), liver and kidney function biomarkers and body weight were determined. Propylthiouracil (PTU) 10 mg/kg was used as reference drug. A. squamosa extract showed a higher total phenolic content and DPPH radical scavenging activity than T. conophorum. Both extracts exhibited dose-dependent inhibition of thyroid peroxidase enzyme, with T. conophorum being more potent. In L-thyroxine-induced hyperthyroid rats, the extracts caused dose-dependent reductions in serum T3, T4, and liver enzymes, with A. squamosa exhibiting superior activity. Serum TSH levels increased in a dose-dependent manner in both extract-treated groups. A. squamosa extract (400 mg/kg) restored hyperthyroidism-induced alterations in body weight, kidney function, and lipid peroxidation to normal levels. These results suggest that A. squamosa and T. conophorum possess antithyroid activity, with A. squamosa showing more potent effects. These findings highlight the potential of A. squamosa and T. conophorum as adjunctive therapies for managing hyperthyroidism.