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Effects of the phenolic fraction from Hippophae rhamnoides fruits on the production of thiobarbituric acid reactive substances (TBARS, a marker of lipid peroxidation) and the generation of superoxide anion (O2 −∙) in human blood platelets (resting platelets and platelets stimulated by a strong physiological agonist, thrombin) were studied in vitro. We also examined antioxidant properties of this fraction against human plasma lipid peroxidation and protein carbonylation induced by a strong biological oxidant, hydrogen peroxide (H2O2) or H2O2/Fe (a donor of hydroxyl radicals). The tested fraction of H. rhamnoides (0.5– 50 µg/mL; the incubation time: 15 and 60 min) inhibited lipid peroxidation induced by H2O2 or H2O2/Fe. The H. rhamnoides phenolic fraction inhibited not only plasma lipid peroxidation, but also plasma protein carbonylation stimulated by H2O2 or H2O2/Fe. Moreover, the level of O2 −∙ in platelets significantly decreased. In comparative experiments, the H. rhamnoides fraction was a more effective antioxidant than aronia extract or grape seed extract (at the highest tested concentration, 50 µg/mL). The obtained results suggest that H. rhamnoides fruits may be a new, promising source of natural compounds with antioxidant and antiplatelet activity beneficial not only for healthy people, but also for those with oxidative stress-associated diseases.

phone: +4861 8569054 S u m m a r yThe aim of this work was to evaluate the antioxidant capacity and flavonoids content in 10 commercial cosmetic plant extracts used in cosmetics industry. Antioxidant activity of plant extracts were measured using two methods: FRAP (Ferric Reducing Antioxidant Power) and TEAC (Trolox Equivalent Antioxidant Capacity). The relationship between flavonoids content and antioxidant capacity of plant extracts were checked. As a result of this research it was found that FRAP and TEAC values of plant extracts significantly depend on the flavonoids content. The highest antioxidant activity, both in FRAP and TEAC assays, was observed for arnica flowers, hawthorn flowers and lungwort herb extracts. These extracts can be used as source of natural antioxidants for the prolongation of the oxidative stability of cosmetic products. Additionally, they can replace synthetic antioxidants.

The effect of commercial cosmetic plant extracts, acerola, willow, and rose, used at the concentrations of 1 and 5%, and 0.01% butylhydroxytoluene (BHT), on the oxidative stability of oil-in-water (o/w) model emulsions containing 5% of wheat germ oil was studied. Considerable differences in total phenolic and flavonoid contents as well as in the TEAC, FRAP, and DPPH antioxidant activities of extracts were observed. Emulsions were stored at 5 and 20°C for 6 months and at 40°C for 4 weeks. The oxidative stability of emulsions was monitored by the determination of peroxide content. The protective effect of plant extracts or BHT on emulsion oxidative stability was expressed as the protection factor (PF). It was found that all 5% extracts were better antioxidants than BHT in emulsions stored at 5°C. Similar results for 5% willow and rose extracts in emulsions stored at 20°C were obtained. PFs of 5% extracts for emulsions stored at 40°C were 2.4-to 3.5-fold lower than this obtained for BHT. Extracts at the concentration of 1%, with an exception of acerola at 20°C, were also effective as antioxidants in tested emulsions but their PFs were about 1.4-5.7 times lower than those of BHT, depending on extract and storage conditions. Altogether, the results obtained revealed that commercial cosmetic plant extracts can be used at the concentrations recommended by their producers (1 or 5%) as natural antioxidants instead of synthetic BHT. Practical application:The results of the present study can be applied in cosmetic industry to improve the quality and safety of emulsions. The studies on oxidative stability of cosmetic emulsions are an important step in the development of cosmetic product technology as they give information about the shelf-life of product and its optimal storage conditions. The chemical composition of the final product should be optimized over a wide range of temperatures to ensure its physical and oxidative stability because the manufacturer is not able to predict conditions under which the cosmetics will be stored by consumers. Higher concentrations (1-5%) of plant extracts in cosmetic emulsions can be applied by the producers to improve not only the physicochemical properties of product, but as multifunctional, skincare cosmetic ingredients.

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