Effect of pre-leaching time before MAE on
percentage extraction of tanshinones

Pre-leaching time at room temperature before
MAE for 2 min influenced the percentage extraction
of tanshinones (Fig. 6). If pre-leaching time was 45
min before MAE, the percentage extraction of tan-shinones can reach the highest. If the pre-leaching
time was more than 45 min, tanshinones had been
partly transferred from the root of Salvia miltiorrhiza
bunge    to solvent before MAE. They were easy to
decompose at high temperature in the solvent [12],
so percentage extraction of tanshinones was de-
creased when pre-leaching time was more than 45
min. Pre-leaching for a short time before MAE was
of benefit for improving the percentage extraction.
Comparison of MAE and conventional
extraction methods

Table 1 shows that MAE only for 2 min, ex-
traction at room temperature for 24 h, ultrasonic
extraction for 75 min, heating reflux extraction for
45 min, Soxhlet extraction for 90 min, MAE can
reach almost the same or even higher percentage
extraction of tanshinones. MAE obviously can re-
duce the extraction time in order to reach the same
percentage extraction.