**3. Materials and Methods**

#### *3.1. Standard*

Oxyresveratrol (>97%), resveratrol, *trans*-stilbene, and copper acetate (Cu(OAc)2) (99.99%) were purchased from Sigma-Aldrich (Buchs, Switzerland); pBR322 Supercoiled plasmid DNA was purchased from Thermo Fisher Scientific (Vilnius, Lithunia); deionized water (<18 MΩ cm resistivity) was obtained from the Milli-Q Element water purification system Millipore S.A.S. (Molcheim, France).

#### *3.2. Plant Material*

The heartwood of *A. lakoocha* was collected from Chanthaburi province, Thailand, in June 2018. The voucher specimen (DMSC 5237) was deposited at the DMSC International Herbarium, Department of Medical Sciences, Ministry of Public Health.
