2.3. Preparation of blackberry leaf mixture extracts
Extraction of polyphenolic compounds from the plain blackberry
leaf and corresponding mixtures was carried out by pouring
300 mL of boiled distilled water over the plant sample (3 g) at
room temperature. After extraction (10 min), the extracts were filtered
through a tea strainer and used for the determination of
polyphenolic compounds.
In order to determine the biological effects of plain blackberry
leaf, the previously prepared extracts were evaporated to dryness,
re-dissolved (and concentrated) in 2 mL of 10% DMSO (dimethyl
sulfoxide). Different concentrations of extracts (ranging from
0.5 to 2.5) were prepared in growth medium (Dulbecco’s Modified
Eagle’s Medium, DMEM). All concentrations of diluted extracts
used in the experiment were checked for the formation of
microscopically apparent crystals to be sure that all components
are in soluble form after dilution of stock solutions in DMEM
(Plochmann et al., 2007).