Standard stock solutions (ca. 200mg L−1) of each glucosidewere
prepared in DMSO, stock solutions of each aglucone in EtOH. These
solutions were stored in amber tightly sealed 8mL vials at 4 ◦C
under exclusion of light. The“weighed-in” concentrationswere verified
by UV-absorbance measurements using the molar extinction
coefficients summarized from literature data by Nurmi et al. [