Preparation of plant materials. T. triandra leaves were purchased from a farmer’s market in a local vegetables
and fruit market of Thailand. The leaves were cleaned with water to remove dust and infected leaves were
separated. The prepared leaves were then dried at 40o
C for 24 h by oven dryer. The dried leaves were
chopped, ground and kept at room temperature in a vacuum-packed container before using.
Solvent extraction. Plant material was oven dried at 40°C for 24 h to reduce water content. Extracts were
prepared by blending preserved plant material (30 g dry weight) in 99% acetone, hexane, ethanol (1:2 w/v
ratios). After 24 h, the mixture was filtered through Whatman filter paper (No.1) using a Buchner funnels. The
solvent was removed with a rotary vacuum evaporator at 40°C. The oil was stored in dark vials at 4°C before
analyzing