The inhibitory activities of compounds 1-10 on RLAR were evaluated.
We also investigated the effects of RLAR inhibitory compounds on sorbitol accumulation in isolated rat lens (results shown in Table 3).
Previous investigations into the inhibitory activities of flavonoids and their derivatives reported that luteolin (10) and luteolin-5-O-[beta]-D-glucopyranoside isolated from Cirsium maackii (A perennial thistle of Asteraceae family) showed inhibitory effects on RLAR comparable to those of the positive control (quercetin).
Crude RLAR was prepared as follows: lenses weighing 250-280 g were removed from Sprague-Dawley rats and frozen at -70[degrees]C until use.
Inhibitory Activity of Isolated Compounds on RLAR. A 70% ethanol extract of SHL was found to exhibit inhibitory activity against RLAR (34.52 [micro]g/mL), AGEs (422.51 [micro]g/mL), and DPPH (193.19 [micro]g/mL) compared with positive controls quercetin (5.48 [micro]g/mL), aminoguanidine (90.70 [micro]g/mL), and L-ascorbic acid (9.58 [micro]g/mL).
The inhibitory behavior of SHL constituents and the related structural activity relationship were investigated using the RLAR assay.
The activities of HRAR and RLAR were according to the procedure of Nishimura (Nishimura et al., 1991).
Inhibitory activities against HRAR and RLAR, of compounds 1, 2 and 3, and quercetin as a positive control, were evaluated.
Compound 3 showed the strongest inhibition of HRAR and RLAR of the three compounds, and its inhibitory activity against HRAR was 60 times more than that of quercetin.
After collection, 96-well plates were evaporated to dryness using an EZ-2 plus evaporator (Genevac Ltd., Ipswich, UK), and RLAR inhibitory activity was evaluated as described in upper section.
The [IC.sub.50] values of RLAR inhibition, except for the EtOAc fraction from the 70% ethanol extract, were higher than 100 [micro]g[mL.sup.-1].
According to our results it is necessary to confirm the presence of effective RLAR inhibitory compounds in the EtOAc fraction of the MA extract.