Improved solubility and increased biological activity of NeoSol™RCL40, a novel Red Clover Isoflavone Aglycones extract preparation

Optimization of the Extraction Conditions of Polyphenols from Red Clover (Trifolium pratense L.) Flowers and Evaluation of the Antiradical Activity of the Resulting Extracts

The purpose of this study was to analyze the effect of the type of extraction solution (water, different concentrations of ethanol), temperature and time on the polyphenol content and antioxidant properties of red clover extracts and the effect of the addition of selected extracts on the antioxidant properties of enriched blackcurrant beverages. In both the extractions carried out under different conditions and in the enriched beverages, the content of selected polyphenols was determined by HPLC. This study confirmed the significant effect of the alcohol content of the extract, extraction time and temperature on the antioxidant properties of clover extracts. Ethanolic extracts had better antioxidant properties than aqueous extracts. The addition of ethanol extracts had a significant effect on the antioxidant properties of the fortified beverages. Increasing the temperature, time or ethanol content in the extracts mostly resulted in an increase in the total polyphenol content in the obtained extracts. Based on the analysis of the response surface, it was found that for the DPPH radical, the best activity was obtained by extraction for 20 min with a solution of approximately 65% at low temperatures. In the case of the ABTS radical, the best antiradical activity was obtained after extraction for 60 min at 80 °C with a solution of approximately 50% ethanol. It was also found that the use of a solution of approximately 60% ethanol after extraction for 60 min at 80 °C would provide an extract with high antiradical activity against both radicals.

Edible Flowers Extracts as a Source of Bioactive Compounds with Antioxidant Properties—In Vitro Studies

Edible plants began to play an important role in past decade as a part of therapy, a recovery process or a healthy life style. The availability and relatively low price of the raw material, as well as proven bioactive health benefits, are key to consumers’ choice of nutrients. The red clover (Trifolium pratense) is a popular plant with healthy properties such as antiseptic and analgesic effects. The less known white clover (Trifolium repens), a fodder and honey plant, has anti-rheumatic and anti-diabetic properties. Both species may serve as a potential source of bioactive substances with antioxidant properties as a food additive or supplement. The study material consisted of flower extracts of Trifolium repens and Trifolium pratense. The total content of polyphenols and DPPH (2.2-diphenyl-1-picrylhydrazyl) and ferric reducing antioxidant power (FRAP) were measured using spectrophotometry methods. Oxidative stress in THP1 cells was induced via sodium fluoride. Subsequently, flower extracts were added and their influences on proliferation, antioxidant potential and the activity of antioxidant enzymes were evaluated. The extracts have a high total content of polyphenols as well as high antioxidant potential. We also demonstrated positive extracts impact on cells proliferation, high antioxidant potential and increasing activity of antioxidant enzymes on cell cultures under high oxidative stress induced by fluoride. Both red clover and the less known white clover may serve as valuable sources of antioxidants in the everyday diet.

Extraction, purification, hypoglycemic and antioxidant activities of red clover (Trifolium pratense L.) polysaccharides

Hot water extraction was applied to extract red clover (Trifolium pratense L.) polysaccharides (RCP) and the extraction conditions were optimized using the response surface methodology (RSM). An RCP yield of 12.72 ± 0.14% was achieved under the optimum extraction conditions: extracting time of 95 min, extracting temperature of 93 °C, and solvent-material ratio of 21 mL/g. A component named RCP-1.1 with the molecular weight of 7528.81 kDa was purified from RCP. RCP-1.1 was composed of glucose, galacturonic acid, arabinose, and galactose, with molar percentages of 52.54, 1.04, 16.31, and 30.11%, respectively. At the determination concentration of 10 mg/mL, the α-glucosidase inhibition ability of RCP-1.1 reached 86.72% of that of acarbose. The scavenging rates of RCP-1.1 (3.0 mg/mL) for DPPH and ABTS radicals reached 91.82% and 98.95% of that of ascorbic acid (3.0 mg/mL), respectively. Based on these results, RCP-1.1 possesses the potential to be used as a natural hypoglycemic agent or an antioxidant.