Some biological activities of dihydroquercetin (DHQ), including antioxidative, antibacterial and anticancer activities, and the oxidative stability of butter oil supplemented with DHQ were evaluated. The DPPH* radical-scavenging activity was high for DHQ, with an IC50 of 63.83 ± 3.11 μg/ml, compared to that of Trolox, which had an IC50 of 117.02 ± 5.19 μg/ml, over the concentrations studied (10–100 μg/ml). At high concentrations (>40 μg/ml), DHQ showed a low scavenging activity for ABTS* radicals, with an IC50 of 99.96 ± 4.59 μg/ml compared to that of Trolox (78.93 ± 2.88 μg/ml). DHQ at a concentration of 12.5–100 μg/ml decreased the surviving fraction of liver (HepG2) and breast (MCF-7) cancer cell lines, with an IC50 value of 78.5 and 124.5 μg/ml, respectively. Additionally, DHQ had good antibacterial activity against both gram-positive (Bacillus cereus, Staphylococcus aureus, and Listeria monocytogenes) and gram-negative (Escherichia coli O157:H7, Pseudomonas aeruginosa, and Yersinia enterocolitica) bacteria. DHQ reduced the oxidation process in butter oil, which caused prolongation of the shelf life (1.9 to 3.53 times), in a concentration-dependent manner (50 to 200 ppm). Finally, DHQ is very important to the health of consumers and can be used to protect dairy foods from oxidation and extend shelf life. Practical applications: The application of dihydroquercetin (DHQ) in the food industry regulates the chemical properties of food products, and the maximum content of DHQ in such products is up to 200 mg/kg fat in the product. The main proposal for using DHQ in foodstuffs is based on its properties, including the ability to reduce oxidative reactions, the ability to strengthen capillaries, and vitamin P activity. Thus, the following advantages were elucidated: DHQ, as an antioxidative agent, could reduce lipid peroxidation and provide the possibility to produce foodstuffs with a higher shelf life, and DHQ can be used for manufacturing products of functional nutrition.
