Title : Flower Infusions from Cornus mas and Cornus kousa Inhibit Aldose Reductase Enzyme
Different species of the genus Cornus L. (Cornaceae) are mostly shrubs or small trees, widely distributed in the northern hemisphere. Four of them, namely Cornus mas, Cornus officinalis, Cornus controversa and Cornus kousa have edible fruits (commonly known as cornelian cherry), that are consumed in different parts of Europe and Asia. The plant parts of Cornus mas L., has been used in ethnomedicine for treatment of cold, flu, urinary inflammation, gastrointestinal disorders, stomach ulcers, colitis (fruits), and diabetes (leaves, seeds). This diverse range of ethnomedicinal utilisation of Cornus mas plant parts was confirmed by several in vitro and in vivo preclinical studies in recent years.
Aldose reductase inhibitors are considered to be potential therapeutical agents for the chronic diabetic complications. Diabetes mellitus could be accompanied by elevated blood level of free fatty acids, which could cause lipotoxicity. Herbal extracts or their constituents are promising agents potentially alleviating these complications. Our study was focused on the influence of mentioned effects by flower infusions from Cornus mas L. and Cornus kousa F.Buerger ex Hance.
Both species are rich in phenolics, Cornus kousa flowers contain slightly higher amounts of phenolic acids (20.79 %) and flavonoids (56.15 %) than Cornus mas (20.20 %) and (47.45 %), respectively. Both extracts showed effective inhibition, expressed as IC50 of adose reductase in non-toxic low concentrations. IC50 = 3.06 mg/mL for Cornus mas, and 2.49 mg/mL for Cornus kousa, respectively. In contrast, these concentrations of both extracts caused almost no effects in the lipotoxicity cell model.
To our knowledge this study is the first report on Cornus mas and Cornus kousa flowers' aldose reductase inhibitory activity, and influence upon lipotoxicity.
Acknowledgment: This work was supported by the Grant Agency of Ministry of Education, Science, Research, and Sport of the Slovak (grant no. VEGA-1/0359/18).