The collected herbal and green tea samples were initially ground
to fine powder and passed through a sieve (40 mesh). The ground
samples were dried to constant weight over a desiccant at room
temperature. For water extraction, 1.00 g of the powdered sample
was extracted with 250 mL of boiling ultra-filtered water. Infusions
were allowed to steep for 1 h with continuous swirling and then
cooled. Subsequently, the infusions were filtered and stored at 4 ◦C
for further analysis within 8 h.