Preparation of samples for quantitative analysis
General procedure for phytosterol content in herbal drugs
The herbal drug was prepared by reflux, using chloroform as
solvent. The extraction was performed in the round-bottomed
flask containing 6.25 g of drug equipment and 30 ml of chloroform
for 30 min. The extract was cooled to room temperature (25°C),
filtered on cotton, and the residue (cotton and plant materials)
re-extracted twice, using 30 ml of chloroform for 15 min. The
filtered fractions were collected in the extract solution and dried
under reduced pressure at 40°C. The residue was resuspended in
20 ml of chloroform, and the volume adjusted to 50 ml with the
same solvent (SM). Aliquots from SM were transferred to 10 ml
volumetric flasks and 2 ml of LB reagent was added. The volume
was adjusted with chloroform. The absorptions were measured
in the UV/Vis spectrophotometer (Evolution 60S, Thermo
Scientific®, Germany), 5 min after addition of the LB reagent.
Chloroform was used as the blank.