No abstract

No abstract

To investigate the mechanistic basis for the biological properties of anthocyanins, two aglycone anthocyanins [delphinidin (DY) and cyanidin (CY)] were used to examine their effects on cell cycle progression and on induction of apoptosis in human cancer cells (uterine carcinoma and colon adenocarcinoma cells) and in normal human fibroblasts. These compounds differ in the number and position of hydroxyl groups on the beta ring in the molecular structure. Cellular uptake of anthocyanins was confirmed by HPLC analysis and no metabolites were detected. The clonogenic assay showed that CY induces a dose-dependent growth inhibitory effect only in fibroblasts. This effect was confirmed by flow cytometric analysis, showing a significant reduction of cells in S phase. In contrast, DP inhibited cell growth in normal and tumour cell lines. This event is accompanied in fibroblasts by an accumulation of cells in the S phase suggesting a block in the transition from S to G2 phase. On the other hand, in tumour cell lines we observed a reduction of cells in G1 phase, paralleled by the appearance of a fraction of cells with a hypodiploid DNA content, thus demonstrating an apoptotic effect by DP. The occurrence of apoptosis induced by DP was confirmed by morphological and biochemical features, including nuclear condensation and fragmentation, annexin V staining, DNA laddering and poly(ADP-ribose) polymerase-1-proteolysis. Furthermore, the mitochondrial membrane potential of apoptotic cells after treatment with DP was significantly lost. The different effects exerted by DP as compared with CY suggest that the presence of the three hydroxyl groups on the beta ring in the molecular structure of DP may be important for its greater biological activity.

Epidemiological and intervention studies correlate anthocyanin-rich beverages and a low incidence of coronary heart diseases. Since endothelin-1 (ET-1) and nitric oxide (NO) produced by endothelial NO synthase (eNOS) are vascular tension regulators secreted by endothelial cells, we studied the influence of two anthocyanidins, namely cyanidin (CY) and delphinidin (DP), on the regulation of ET-1 and eNOS in cultured human umbilical vein endothelial cells (HUVECs). Aglycon anthocyanidin forms, such as CY and DP, may be present in vivo after the first deglycosylation step occurring in the jejunum and in the liver. DP showed a major action compared to CY inducing a significant dose-dependent inhibitory effect on both protein and mRNA levels of ET-1. CY and DP both increased the protein level of eNOS, but DP showed the major effect raising eNOS protein in a dose-dependent manner. To correlate the vasoprotective effect of CY and DP with their antioxidant activity, we analysed also the antioxidant effect of anthocyanidins both in vitro and in HUVECs. In particular, we examined the effect of anthocyanidins on endothelial heme oxygenase-1 (HO-1), an inducible stress protein. In all tests, DP showed a higher antioxidant activity than CY. Finally, the antiproliferative effect induced by DP was detected in HUVECs. DP and CY differ in the number and position of hydroxyl groups in their structure; therefore, the greater biological activity by DP, compared with CY, seems to be due to the presence of the three hydroxyl groups on the B ring in the molecular structure of DP.

Grape waste management is one of the main problems of winery industries, but, conversely, grape waste contains a high amount of polyphenols that might protect against human diseases related to oxidative stress, such as colorectal cancer. Therefore, the aim of this work was to investigate the antioxidant and antiproliferative activities of a grape waste extract obtained by supercritical fluid extraction. Because the beneficial effect of grape is related to its content of polyphenolic molecules, the extract was chemically characterized by high-performance liquid chromatography in order to assess its major bioactive components. The antioxidant activity of the grape extract was determined. The results showed that the grape extract presents a strong antiradical activity in the in vitro 2,2-diphenyl-1-picrylhydrazyl radical assay and protects against reactive oxygen species production in human colon adenocarcinoma cells (Caco-2). In contrast, the extract did not protect in the citronellal thermooxidation system and showed a weak protective action against lipid peroxidation in Caco-2 cells. The clonogenic assay and the cell cycle distribution analysis showed that the grape extract has a significant antiproliferative effect in a tumor cell line. These data indicate that grape extract is a promising product to be used as an anti-free radical agent and could exert a chemopreventive action.

No abstract

No abstract

Lettuce belongs to the Asteraceae family and it is native of the Mediterranean region. In our research, the effect of cultivation practices (organic versus conventional) on antioxidants in Italian head lettuce (Lactuca sativa var. capitata L.) grown in greenhouse was investigated. Bioactive molecule levels, antioxidant properties and the cytotoxicity of polyphenolic extracts from the edible part of head lettuce in Caco-2 cells were determined. FRAP values are 5.33 Ϯ 0.35 and 6.35 Ϯ0.08 mmol/kg in organic products and 4.83 Ϯ 0.16 and 1.80 Ϯ 0.04 mmol/kg in conventional products. FRAP values differ significantly (P < 0.001) between organic and conventional lettuces harvested in September. Significant differences are found between organic and conventional extracts in some target compounds such as quercetin, rutin, lutein, b-carotene and vitamin C. No difference in biological effect is observed between organic and conventional products harvested in July and in September, whereas a major cytotoxicity is found for polyphenol extracts derived from organic and conventional lettuces harvested in September. PRACTICAL APPLICATIONSNowadays, a new image of agriculture is emerging: agricultural production systems are closely related to the needs of consumers and to the search of products that meet food quality and safety. The results of this investigation highlighted the importance of factors such as cultivar, agronomic practices, climatic conditions, degree of ripeness, time of harvest and storage conditions. The variation of these elements represents, in fact, a key tool to obtain healthful and more nutritious food crops by increasing and maximizing the levels of bioactive molecules in foods. Our results suggest a potential to increase the commercial production of the selected specialty leafy greens. bs_bs_banner Journal of Food Biochemistry ISSN 1745-4514 56 Journal of Food Biochemistry 38 (2014) 56-61 © 2013 Wiley Periodicals, Inc. † Values are expressed as mean values Ϯ SD. Means in row for each compound followed by different letters differed significantly (P < 0.05). ‡ By column, levels of significance are represented by NS (not significant), * P < 0.05 and ** P < 0.01. ANTIOXIDANTS IN ITALIAN HEAD LETTUCEA. DURAZZO ET AL.