were ground separately, sieved through a 60 mesh screen and defatted
using four volumes of petroleumether. The dried residues, after removing
petroleum ether, were extracted thrice with four volumes of 90%
ethanol by shaking for 1 h followed by filtration. The filtrates from
each material were concentrated in a rotavapor and then frozen overnight
and freeze–dried at −60 °C. Cao et al. (2013) prepared extracts
from ginger, onion and garlic by mixing about 100 g each of three
chopped spices with 600 mL of distilled water and extracted for
30 min at 40 °C in enclosed flasks with ultrasonic extractor (200 W,
40 kHz). After filtration (Whatman No. 1 filter paper), the residue was
re-extracted with an additional 400 mL of distilled water for additional
30 min, filtered and the all the filtrates were combined.