Preparation of the Haldu extract
Plant material were collected from Chainat province, the central province of Thailand.
Dried and powdered of bark and leaves (500g) were extracted with methanol for 7 day at
room temperature, filtered and concentrated. The aqueous residues were extracted with
chloroform (CHCl3) and the chloroform fractions were evaporated to dryness, dissolved in
methanol and kept under -45°C for further analyses.