Phenolic compounds from the leaves of Homonoia riparia and their inhibitory effects on ages formation and aldose reductase

In searching for novel treatments for diabetic complications from natural resources, we found that the EtOAc-soluble fraction of the 80% EtOH extract of the leaves of Homonoia riparia has a considerable inhibitory effects on both AGEs (Advanced glycation end products) formation and rat lens aldose recuctase (RLAR). Further phytochemical study of this fraction resulted in the isolation of 15 phenolic compounds (1 – 15). These compounds were evaluated in vitro for inhibitory activity against the formation of AGEs and RLAR. In the AGEs assay, compounds 3, 5 – 7, 10, 11, and 14 significantly inhibit the AGEs formation with IC₅₀ values ranging from 2.23 to 15.14µM, compared to that of positive control, aminoguanidine (IC₅₀, 962µM). In the RLAR assay, compound 4, quercitrin gallate, showed the most potent inhibitory activity with an IC₅₀ value of 0.064µM.