Background: Sea buckthorn is a good and possible source of a wide range of bioactive compounds with a positive effect on the human body, especially polyphenols and carotenoids.
Methods: The present study aimed to evaluate the antioxidant and antimicrobial activities of Hippophae rhamnoides L. products - 100% oil, 100% juice, dry berries, and tea (dry berries, leaves, and twigs). The antioxidant activity was determined by DPPH radical scavenging and molybdenum reducing antioxidant power methods. The content of phytochemicals (polyphenols, flavonoids, carotenoids) was measured by colorimetric methods. The detection of antimicrobial activity was carried out using the disc diffusion method and an evaluation of minimal inhibition concentration against three species of Gram-negative bacteria: Escherichia coli CCM 3988, Salmonella enterica subsp. enterica CCM 3807, Yersinia enterocolitica CCM 5671, and three Gram-positive bacteria: Bacillus thuringiensis CCM 19, Listeria monocytogenes CCM 4699, Staphylococcus aureus subsp. aureus CCM 2461.
Results: All the tested sea buckthorn products had a high antioxidant activity. The highest content of total polyphenols (204.26 mg GAE/g), flavonoids (30.00 mg QE/g), and carotenoids (0.34 mg/g) were identified in 100% sea buckthorn juice. Maximal values of the antioxidant activity were found using the DPPH method for 100% oil (8.75 mg TE/g) and molybdenum reducing power for tea (196.41 mg TE/g). All the tested products showed strong antimicrobial activity against the tested bacteria, confirmed by both methods - disc diffusion (especially for Yersinia enterocolitica CCM 5671) and minimal inhibitory concentration.
Conclusions: The pronounced antioxidant and antibacterial properties of sea buckthorn products indicate the importance of sea buckthorn application in health promotion and agricultural practice.
Keywords: Hippophae rhamnoides; antimicrobial activity; carotenoids; flavonoids; polyphenols.