Preparation of plant extracts
Three batches of 28 plant materials, classified into four
groups as plant leaf, flower, fruit and seed (Table 1), were
purchased from market places in Thailand from March to
June in 2004–2005. Each plant sample (50 g) was ground
with 95% ethanol (150 mL) in a blender for 1 min and
shaken in the dark at 25 1C for 4.5 h. The extract was
evaporated to dryness using a rotary evaporator at 50 1C
and stored under nitrogen at 20 1C until it was analyzed.
Extraction was done in duplicate.