Air-dried leaves were pulverized by grinding and then macerated,
at room temperature, with absolute methanol for 7 days,
twice, while stirring 2–3 times/day. The extracts were mixed, filtered
and concentrated using a rotary evaporator (BUCHI, B 169
Vacumn-System, Switzerland). Then they were freeze-dried (Corrosion
Resistant Freezer Drier, FTS System, Inc., USA). The yield was
7.92% (w/w).