American Cranberry (Oxycoccus macrocarpus) Leaves Extract and Its Modified Arginine Preparation for the Management of Insulin Resistance

Metabolic syndrome is a cluster of abnormalities combining insulin resistance (IR), obesity, hypertension, and atherosclerotic hyperlipidemia suggested to be a pandemic by WHO experts. In Ukraine, bilberry leaves (Vaccinium myrtillus, Ericaceae) are widely used as a hypoglycemic agent. American cranberry (AC) could be of particular interest for IR prevention. During cultivating, AC bushes are pruned annually; leaves act as by- products and are interesting for supplements with hypoglycemic activity development.

The aim was to study the chemical composition and hypoglycemic activity of AC leaves extract and its arginine preparation.

AC leaves were macerated (1:10) twice with 50% ethanol at room temperature, evaporated to the dry extract (E1). The content of phenolic substances in the liquid extract was 1.04%, arginine was added at three times equimolar amount to them. E1 is a brown loose powder, its arginine preparation (E2) – a viscous mass.

In the extracts, quinic, 3-caffeoylquinic (chlorogenic), p-coumaroylquinic acids, quercetin 3-O-galactoside, quercetin-3-O-glucoside, quercetin-3-xyloside, quercetin-3-O-arabinopyranoside, quercetin-3-O- arabinofuranoside, quercetin 3-O-rhamnoside and quercetin-O-p-coumaroyl-hexoside-2 were identified by HPLC. Assay of phenolic compounds, flavonoids and hydroxycinnamic acids were determined by spectrophotometry. The oral glucose tolerance test with the extracts demonstrated positive dynamics in IR correction. E2 administration showed reducing glycemia by 22.6%. AC extracts restored insulin concentration compared with metformin. They had positive effect on liver lipid content, reducing triacylglycerols, diacylglycerols and free fatty acids.

The studies revealed potential of AC leaves extracts in prevention of insulin-resistance, which can be additionally augmented by conjugation with L-arginine.

Funding This work was supported by the MSCA4Ukraine (1232466).

Publikationsverlauf

Artikel online veröffentlicht:
16. November 2023