Preparation of the extracts
Minced fresh rhizome knots and dried leaves of N. nucifera were
extracted with distilled water at room temperature overnight. The
extracts were filtered, and the solvent removed by rotary evaporation
at 35 °C. The residues were evaporated to dryness in vacuo and the
resulting dry powder was stored at 4 °C. The yield of LRK and LL
extracts were 6.6±0.3% and 10.3±0.6%, respectively