Inhibitory effects of compounds isolated from Thuja orientalis on human recombinant aldose reductase and advanced glycation end-products

The aim of work was to evaluate active principles for diabetic complications from Thuja orientalis. Seven compounds were isolated via bioactivity guided fractionation and tested for their effects on recombinant human aldose reductase and advanced glycation end products.

From those compounds, quercitrin isolated from ethyl acetate fraction was found to be a strong inhibitor of recombinant human aldose reductase. The inhibitory potency of quercitrin (IC₅₀ value: 1.2µM) and hypoletin-7-xylopyranoside (IC₅₀ value: 1.2µM) against a recombinant human aldose reductase was similar to that of epalrestat which was used as positive control (IC₅₀ value: 0.7µM). The inhibitory potency of quercitrin (IC₅₀ value: 77.8µM) and amentoflavon (IC₅₀ value: 97.1µM) on advanced glycation end-products was about more than 15 times that of aminoguanidine as a positive control (IC₅₀ value: 1500.0µM).

Overall findings suggest, therefore, the EtOAc fraction from T. orientalis inhibit recombinant human aldose reductase as well as advanced glycation endproducts. Especially, quercitrin isolated from EtOAc fraction was the potentially active compound of this plant.

As a result, these could be proposed as a leading plant extract and/or compound for further study as a new drug from natural products that could be used for diabetic complications.