Preparation of the Aqueous Extract

The aqueous extract was prepared by decoction, according to Afonso et al. (2017), with adaptations. Aerial parts T. serrulatus were shed dried and then powdered. The powdered plant material (20 g) was mixed with distilled water (400 ml) and then boiled for 15 min, left to cool for 5 min, and filtered through Whatman grade 1 filter paper, using a pressurized suction filtration system. Upon concentration in vacuo at 40°C, the filtrate was defatted with n-hexane (1:1 v/v). The resulting aqueous extract was freeze-dried, sealed, and kept in a refrigerator for further use. A fresh stock solution was prepared for the experiment whenever required.