Biological activity and stability in vitro of polyphenolic extracts as potential dietary supplements

In times of worsening civilization diseases the interest in natural healing substances is on the increase. To reduce unwanted side effects of many synthetic drugs, it is reasonable to introduce to the daily diet foods rich in natural compounds of plant origin that are beneficial for health. The purpose of the study was to determine the biological activity and stability of selected ethanol extracts of the fruit of chokeberry, blackcurrant, hawthorn, rosehip, quince and Japanese quince as potential nutraceuticals.

Antioxidant activity of the extracts was determined in relation to model phospholipid membranes (IC50(PC)). Antiradical activity was determined in a test with the DPPH• radical (IC50(DPPH)). Also the inhibition of enzymatic (1-LOX) oxidation of linoleic acid was determined at the beginning of the period of storage of the extracts at room temperature and after 12 months.

After 12 months of storage the highest antioxidant stability was shown by blackcurrant extract (1.5% increase in IC50(PC)), the highest antiradical stability by quince extract (1.0% reduction in IC50(DPPH)), and the highest stability of 1-LOX enzyme inhibition by chokeberry extract (6.3% reduction in inhibition at a concentration of 8 μg∙(-1)). Japanese quince extract showed the strongest regenerating properties with respect to oxidized phospholipid membranes and the highest ability to eliminate the free radical DPPH•.

It can be concluded that the ethanol extracts of the fruits (in particular blackcurrant, chokeberry and Japanese quince) are a potential source of dietary supplements of expected effectiveness in preventive treatment.