No abstract

The aim of the present research was to determine the effect of blue honeysuckle fruit and leaf extracts components on the physical properties of erythrocyte and lipid membranes and assess their antioxidant properties. The HPLC analysis showed that the extracts are rich in polyphenol anthocyanins in fruits and flavonoids in leaves. The results indicate that both extracts have antioxidant activity and protect the red blood cell membrane against oxidation induced by UVC irradiation and AAPH. The extracts do not induce hemolysis and slightly increase osmotic resistance of erythrocytes. The research showed that extracts components are incorporated mainly in the external part of the erythrocyte membrane, inducing the formation of echinocytes. The values of generalized polarization and fluorescence anisotropy indicate that the extracts polyphenols alter the packing arrangement of the hydrophilic part of the erythrocyte and lipid membranes, without changing the fluidity of the hydrophobic part. The DSC results also show that the extract components do not change the main phase transition temperature of DPPC membrane. Studies of electric parameters of membranes modified by the extracts showed that they slightly stabilize lipid membranes and do not reduce their specific resistance or capacity. Examination of IR spectra indicates small changes in the degree of hydration in the hydrophilic region of liposomes under the action of the extracts. The location of polyphenolic compounds in the hydrophilic part of the membrane seems to constitute a protective shield of the cell against other substances, the reactive forms of oxygen in particular.

Compounds contained in fruits and leaves of blackcurrant (Ribes nigrum L.) are known as agents acting preventively and therapeutically on the organism. The HPLC analysis showed they are rich in polyphenol anthocyanins in fruits and flavonoids in leaves, that have antioxidant activity and are beneficial for health. The aim of the research was to determine the effect of blackcurrant fruit and leaf extracts on the physical properties of the erythrocyte membranes and assess their antioxidant properties. The effect of the extracts on osmotic resistance, shape of erythrocytes and hemolytic and antioxidant activity of the extracts were examined with spectrophotometric methods. The FTIR investigation showed that extracts modify the erythrocyte membrane and protect it against free radicals induced by UV radiation. The results show that the extracts do not induce hemolysis and even protect erythrocytes against the harmful action of UVC radiation, while slightly strengthening the membrane and inducing echinocytes. The compounds contained in the extracts do not penetrate into the hydrophobic region, but bind to the membrane surface inducing small changes in the packing arrangement of the polar head groups of membrane lipids. The extracts have a high antioxidant activity. Their presence on the surface of the erythrocyte membrane entails protection against free radicals.

Trihydroxyflavones of Scutellaria baicalensis, Antioxidant Activity, Liposome, Peroxidation, MDA The antioxidant effect of a trihydroxyflavone extract from Scutellaria baicalensis on oxida­ tion induced by ultraviolet light, was studied with phosphatidylcholine liposome membrane. Also, as standards, the antioxidative activity of baicalin, wogonin, baicalein and butylated hydroxytoluene (BHT) was investigated. Comparison of the protective effects of thecom­pounds studied against photoinduced lipid peroxidation in lecithin liposome membranes showed that: (1) the inhibitory effect of those compounds (at 1.2 mol% antioxidant content in liposomes) on TBA reactive materials from lipid peroxidation decreased in the order of baicalin > BHT ≅ Scutellaria baicalensis. These were found much greater than wogonin and baicalein; (2) the depressed effect of those compounds (at 1.1 mol% compounds content in liposomes) on the production of conjugated dienes (proportional to oxidation index) could be classified as follows: Scutellaria baicalensis ≅ baicalin > BHT, these three were found more active much greather than baicalein and wogonin. Results obtained by ESR measure­ment confirm that Scutellaria baicalensis extract and the BHT compound significantly de­ pressed the effect of liposome oxidation. It was found that the new trihydroxyflavones of Scutellaria baicalensis, ensured a very satisfactory concentration-dependent protection of the liposome membrane against UV-induced oxidation. These findings suggest that some of the beneficial effects of the extract of the Scutellaria baicalensis can be mediated in certain diseases (for example in skin diseases) by their ability to scavenge free radicals and by their protective effect on lipid peroxidation caused by sunlight irradiation.