[Health--promoting effect of quercetin in human diet]. / Prozdrowotna rola kwercetyny obecnej w diecie cz³owieka

Quercetin is a plant flavonoid phytochemical exhibiting a broad spectrum of properties i.a. antioxidant, anti-inflammatory and immunomodulatory. However, the effect of quercetin is not clear. This compound at low concentrations can stimulate proliferation of human cells, so it can be a potential drug in the treatment of neurodegenerative diseases and in high concentrations, it induces apoptosis thereby eliminating the infected or abnormal cells and can serve as a potential anticancer drug with wide clinical application. Action of quercetin can be explained by its interference with cellular enzymes, receptors, transporters and signalling system. Due to its widespread occurrence in the plant world, it is an integral component of the human diet. The dietary quercetin occurs most often in the form of ß-glycosides connected mostly with rutinose, rhamnose and glucose. Depending on the nutritional habits, the daily intake of flavonoids, including quercetin, ranges from 3 to 70 mg. Epidemiological studies confirm an inverse correlation between the consumption of flavonoids and the incidence of lifestyle diseases and tumor formation. Published data indicate that consumption of foods rich in flavonoids reduces the risk of coronary heart disease. Thus, flavonoids - including quercetin - seem to be an interesting pro-health agent.

Red cabbage anthocyanin extract alleviates copper-induced cytological disturbances in plant meristematic tissue and human lymphocytes.

Red cabbage is a source of health beneficial substances with antioxidant and antigenotoxic properties. HPLC analysis specifying the content of the investigated extract indicated that mainly anthocyanins (ATH) were responsible for its abilities. Cytological research was conducted with two experimental models: plant tissues--meristematic cells of Vicia faba, and animal tissue elements--human lymphocytes. Positive influence of ATH extract on mitotic activity of Vicia cells exposed to Cu(2+) stress, and inhibitory effect of ATH on cytotoxic actions of Cu(2+) on lymphocytes were demonstrated. In all experimental series with ATH application in combinations with Cu(2+), mitotic index (MI) were higher than those obtained for only Cu(2+) stressed tissues. Preincubation in ATH before Cu(2+) stress had the best effect. Similarly, after ATH applications in all tested series decrease in frequency of micronuclei (MN) appearance was noticed in comparison with only Cu(2+) stressed material. In the case of Vicia cells ATH acted effectively even applied after Cu(2+) stress. It suggests that this ATH mixture not only prevents and limits but also heals the cytological injury caused by Cu(2+) stress.

The impact of Cu treatment on phenolic and polyamine levels in plant material regenerated from embryos obtained in anther culture of carrot.

The influence of copper sulphate on the regeneration of carrot (Daucus carota L.) androgenic embryos and changes in the levels of phenolic substances and polyamines that might be indicative of the response to oxidative stress were investigated. The cultivation on the regeneration medium supplemented with Cu(2+) at the concentrations 1 and 10 microM for 15 weeks resulted in significant dose-dependent inhibition of the growth and organogenic ability of carrot embryos. The total content of phenolic acids (represented by the sum of all soluble and insoluble fractions) in the Cu(2+)-treated carrot cultures did not change in comparison with the control (0.1 microM Cu(2+)). However, the levels of phenolic acids in the individual fractions showed significant differences. The cultivation in the presence of increased Cu(2+) evoked first of all the rise of free chlorogenic and caffeic acids, and the increase in soluble ester-bound ferulic acid. Marked dose-dependent decline in the amount of ferulic acid incorporated into the cell walls of the Cu(2+)-treated carrot cultures was partly compensated by the increase in the content of p-hydroxybenzoic acid. Decline in the total polyamine contents in the carrot tissues cultivated in the presence of increased Cu(2+) concentrations was observed. The most abundant polyamine, both in a free and PCA-soluble conjugated forms, was putrescine, the least abundant was spermine, which occurred in free form only. While the levels of free polyamines slightly decreased in a dose-dependent manner in the Cu(2+)-treated cultures, those of PCA-soluble conjugates markedly rose (enhancement to 135 and 170% in 1 and 10 microM Cu(2+), respectively, compared with the control). The decline in the total polyamine contents was caused mainly by the decline in the levels of PCA-insoluble conjugates. The decrease observed in this fraction was approximately to 70 and 50% in 1 and 10 microM Cu(2+)-treated cultures, respectively, when compared with the control. The role of phenolic acids and polyamines in preventing Cu(2+)stress in the carrot tissues is discussed.