Flower Infusions From Cornus mas and Cornus kousa Inhibit Aldose Reductase Enzyme, Without Any Effects on Lipotoxicity

Abstract

Aldose reductase inhibitors are considered to be potential therapeutic agents for chronic diabetic complications. Diabetes mellitus can be accompanied by elevated blood levels of free fatty acids, which can cause lipotoxicity. Herbal extracts and their constituents are promising agents which have the potential for alleviating these complications. Our study was focused on the influence on these effects by flower infusions from Cornus mas L. and Cornus kousa F.Buerger ex Hance. Initially, phenolic compounds were quantified in the dried flowers. Next, we studied the ability of flower infusions from both plants to inhibit aldose reductase in vitro, the protective role in the cell model of lipotoxicity, and the cytotoxic action on fibroblast cell line NIH-3T3 by 3-(4,5-dimethyl-2-thiazolyl)-2,5-diphenyl-2 H-tetrazolium bromide assay. Both species are rich in phenolics; C. kousa flowers contain slightly higher amounts of phenolic acids (20.8%) and flavonoids (56.1%) than C. mas (20.2%) and (47.4%), respectively. Both extracts showed effective inhibition, expressed as half-maximal inhibitory concentration (IC50) (the concentration of inhibitor required to exhibit 50% inhibition of the enzyme reaction), of aldose reductase in non-toxic low concentrations (IC50 = 3.06 μg/mL for C. mas and IC50 = 2.49 μg/mL for C. kousa, respectively). In contrast, these concentrations of both extracts had almost no effects in the lipotoxicity cell model. To our knowledge, this study is the first report on C. mas and C. kousa flowers’ aldose reductase inhibitory activity and influence upon lipotoxicity.

The Possibility of Using Fruit-Bearing Plants of Temperate Climate in the Treatment and Prevention of Diabetes

“…Due to their high phenolic acid and flavonoid content, Cornelian cherry flowers may be a potential therapeutic agent in chronic complications of diabetes, as they weaken the effect of aldehyde reductase. Forman et al [ 38 ] determined the ability of C. mas flower infusions to inhibit aldose reductase in vitro. They found that the activity of the compounds in the flower infusion was close to the IC50 values of pure plant metabolites, for example, chlorogenic acid, gallic acid, and quercetin, used as references for plant aldose reductase inhibitors.…”

The Health-Promoting Quality Attributes, Polyphenols, Iridoids and Antioxidant Activity during the Development and Ripening of Cornelian Cherry (Cornus mas L.)

“…Ripe CC has been widely discussed in the scientific literature over the last decades. The fruits of this plant, as well as its flowers, leaves, and stones, provide an array of chemical compounds, including natural antioxidants [1,[3][4][5][6]. They contain polyphenols (phenolic acids, hydrolysable tannins, anthocyanins, flavonols), iridoids, vitamin C, fiber, and unsaturated fatty acids [1,2].…”