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  • Author: Jana Viskupičová x
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Lipophilization of flavonoids for their food, therapeutic and cosmetic applications

Lipophilization of flavonoids for their food, therapeutic and cosmetic applications

Flavonoids represent large group of plant pigments. These polyphenolic compounds may be found in the nature as active components of fruits, vegetables and other plants and derived products. Due to established biological effects they are attractive substances for many areas of human life. Many flavonoids are nowadays used in pharmaceutical, cosmetic and food preparations. Their practical applications are in most cases limited by low solubility and stability in lipophilic media. Chemical or enzymatic lipophilization of flavonoid skeleton may not only increase their solubility and stability in lipophilic environment but also their biological properties. This review summarizes current knowledge in this field.

Open access
Pycnogenol® and Ginkgo biloba extract: effect on peroxynitrite-oxidized sarcoplasmic reticulum Ca2+-ATPase

Pycnogenol® and Ginkgo biloba extract: effect on peroxynitrite-oxidized sarcoplasmic reticulum Ca2+-ATPase

The effect of two natural standardized plant extracts, Pycnogenol® and EGb 761, on sarcoplasmic reticulum Ca2+-ATPase (SERCA) activity and posttranslational modifications induced by peroxynitrite was investigated to assess their possible protective role. EGb 761 was found to have a protective effect on SERCA activity in the concentration range of 5-40 μg/ml. On the other hand, Pycnogenol® caused a decrease of SERCA activity at concentrations of 25 μg/ml. EGb 761 did not prevent protein carbonyl formation upon oxidation with peroxynitrite. On the contrary, Pycnogenol® at the concentrations of 5 and 10 μg/ml significantly decreased the level of protein carbonyls by 44% and 54%, respectively. Neither Pycnogenol® nor EGb 761 exerted a protective effect against thiol group oxidation. The plant extracts studied modulated peroxynitrite-injured SERCA activity by different ways and failed to correlate with posttranslational modifications. Their effect seems to be associated with their ability to change SERCA conformation rather than by their antioxidant capacity.

Open access
Modulation of rabbit muscle sarcoplasmic reticulum Ca2+-ATPase activity by novel quercetin derivatives

Abstract

Sarcoplasmic reticulum Ca2+-ATPase (SERCA) is the pump crucial for calcium homeostasis and its impairment results in pathologies such as myopathy, heart failure or diabetes. Modulation of SERCA activity may represent an approach to the therapy of diseases with SERCA impairment involvment. Quercetin is flavonoid known to modulate SERCA activity. We examined the effect of nine novel quercetin derivatives on the activity of the pump. We found that 5-morpholinohydroxypoxyquercetin, di(prenylferuoyl)quercetin, di(diacetylcaffeoyl)-mono-(monoacetylcaffeoyl)quercetin and monoacetylferuloylquercetin stimulated the activity of SERCA. On the contrary, monochloropivaloylquercetin, tri(chloropivaloyl)quercetin, pentaacetylquercetin, tri(trimethylgalloyl)quercetin and diquercetin inhibited the activity of the pump. To identify compounds with a potential to protect SERCA against free radicals, we assessed the free radical scavenging activity of quercetin derivatives. We also related lipophilicity, an index of the ability to incorporate into the membrane of sarcoplasmic reticulum, to the modulatury effect of quercetin derivatives on SERCA activity. In addition to its ability to stimulate SERCA, di(prenylferuloyl)quercetin showed excellent radical scavenging activity.

Open access
Biologically valuable components, antioxidant activity and proteinase inhibition activity of leaf and callus extracts of Salvia sp.

Abstract

Sage is medicinal plant, known for its antioxidant and anti-inflammatory effects. Eight extract samples were tested in this study: extract from Salvia officinalis L. varieties from two different geographical localities (Jaslovské Bohunice and Pobedim, Slovakia), Salvia officinalis L., variety “bicolor”, Salvia officinalis L., variety “purpurescens”, Salvia apiana, Salvia divinorum, and two callus cultures of Salvia sclarea L. and Salvia aethiopis L. The highest values for composite parameters were observed for extract from Salvia apiana. It can be concluded that prepared sage extract samples are rich on polyphenolic acids (2 950±265 μg.mL−1 GAeq.) and amines (197±5.50 μg.mL−1 TRPeq.). HPLC analysis confirmed the dominant content of rosmarinic acid in the extracts; the highest content was detected in the Salvia apiana extract (1 120±15 μg.mL−1). Extract from Salvia apiana expressed too the highest antioxidant activity (1 710 – 4 669 μg.mL−1TEAC). Similarly, the highest inhibition activity was observed for this extract on thrombin (57±3.3 %) and on other proteinases (over 80 %). Spearman correlation analysis and PCA analyses revealed a coherence between antioxidant activity of samples and their content of rosmarinic acid as well as inhibitory activity towards particular proteases, and revealed the significance of thiol based secondary metabolites. Cluster analysis demonstrates the differences of Salvia apiana extract from extracts of S. officinalis L., the group of S. divinorum extract and from callus cultures.

Open access