agar and epigallocatechin-gallate

Diet rich in polyphenols may be important factor in preventing cardiovascular, neoplastic diseases and slowing down the aging processes. Because tea (Camelia sinensis) is most popular beverage containing relatively large amounts of polyphenols, it could be tremendously important source of polyphenolic constituents in human diet. However, there has been no data on the tea extracts use in particular everyday snacks. Objective of the study was to investigate potential use of tea polyphenol extracts in jelly candies, its taste, colour, consistency and general consumer's acceptance. Sensory analyses were conducted on two kinds of sweet jellies, with gelatin and agar used as thickening agents. As polyphenol source green and black tea extracts (Camellia sinensis) were used at concentration of 1.0% and 1.5%. Total polyphenol content in jellies ranged between 245.9-1256.5 mg/100g of candies and EGCG (epigallocatechin gallate) strong antioxidant content ranged between 3.2-170.1 mg/100g of candies. Sensory analyses included evaluation of overall appearance, colour, taste, aroma, consistence (homogenicity, clot presence) and clarity of jellies. Comparison of two thickening agents resulted in better properties of gelatin jellies according to its quality: colour, clarity, consistence, taste and aroma (p<0.05). It was found that agar containing jellies were not so clear and aromatic as compared with gelatin (p<0.05). Colour and overall appearance was also much more acceptable by the consumers in gelatin jellies. According to tea extract used it was found that ethanol extracts resulted in lower acceptance for overall acceptance and consistency (p<0.05). Present study indicated that tea polyphenols extracts were accepted by consumers as food product constituents, and might be an interest of wider usage as food components.

Topics: Agar; Antioxidants; Candy; Catechin; Consumer Behavior; Dose-Response Relationship, Drug; Flavonoids; Food Technology; Gelatin; Humans; Oxidation-Reduction; Phenols; Plant Extracts; Polyphenols; Taste; Tea

Melanoma accounts for only about 4% of all skin cancer cases but most of skin cancer-related deaths. Standard systemic therapies such as interferon (IFN) have not been adequately effective in the management of melanoma. Therefore, novel approaches are needed for prevention and treatment of this disease. Chemoprevention by naturally occurring agents present in food and beverages has shown benefits in certain cancers including nonmelanoma skin cancers. Here, employing 2 human melanoma cell lines (A-375 amelanotic malignant melanoma and Hs-294T metastatic melanoma) and normal human epidermal melanocytes (NHEM), we studied the antiproliferative effects of epigallocatechin-3-gallate (EGCG), the major polyphenolic antioxidant present in green tea. EGCG treatment was found to result in a dose-dependent decrease in the viability and growth of both melanoma cell lines. Interestingly, at similar EGCG concentrations, the normal melanocytes were not affected. EGCG treatment of the melanoma cell lines resulted in decreased cell proliferation (as assessed by Ki-67 and PCNA protein levels) and induction of apoptosis (as assessed cleavage of PARP, TUNEL assay and JC-1 assay). EGCG also significantly inhibited the colony formation ability of the melanoma cells studied. EGCG treatment of melanoma cells resulted in a downmodulation of anti-apoptotic protein Bcl2, upregulation of proapoptotic Bax and activation of caspases -3, -7 and -9. Furthermore, our data demonstrated that EGCG treatment resulted in a significant, dose-dependent decrease in cyclin D1 and cdk2 protein levels and induction of cyclin kinase inhibitors (ckis) p16INK4a, p21WAF1/CIP1 and p27KIP1. Our data suggest that EGCG causes significant induction of cell cycle arrest and apoptosis of melanoma cells that is mediated via modulations in the cki-cyclin-cdk network and Bcl2 family proteins. Thus, EGCG, alone or in conjunction with current therapies, could be useful for the management of melanoma.

Topics: Agar; Anticarcinogenic Agents; Apoptosis; bcl-2-Associated X Protein; Caspase 3; Caspase 7; Caspase 9; Caspases; Catechin; Cell Cycle; Cell Cycle Proteins; Cell Line, Tumor; Cell Proliferation; Cell Separation; Cell Survival; Cyclin-Dependent Kinase Inhibitor p16; Cyclin-Dependent Kinase Inhibitor p21; Dose-Response Relationship, Drug; Down-Regulation; Flow Cytometry; Humans; Immunoblotting; Immunohistochemistry; In Situ Nick-End Labeling; Ki-67 Antigen; Melanocytes; Melanoma; Membrane Potentials; Mitochondria; Poly(ADP-ribose) Polymerases; Proto-Oncogene Proteins c-bcl-2; Time Factors