cryptoxanthins and Skin-Neoplasms

The glaucophyte Cyanophora paradoxa (Cp) was chemically investigated to identify pigments efficiently inhibiting malignant melanoma, mammary carcinoma and lung adenocarcinoma cells growth. Cp water and ethanol extracts significantly inhibited the growth of the three cancer cell lines in vitro, at 100 µg · mL(-1). Flash chromatography of the Cp ethanol extract, devoid of c-phycocyanin and allophycocyanin, enabled the collection of eight fractions, four of which strongly inhibited cancer cells growth at 100 µg · mL(-1). Particularly, two fractions inhibited more than 90% of the melanoma cells growth, one inducing apoptosis in the three cancer cells lines. The detailed analysis of Cp pigment composition resulted in the discrimination of 17 molecules, ten of which were unequivocally identified by high resolution mass spectrometry. Pheophorbide a, β-cryptoxanthin and zeaxanthin were the three main pigments or derivatives responsible for the strong cytotoxicity of Cp fractions in cancer cells. These data point to Cyanophora paradoxa as a new microalgal source to purify potent anticancer pigments, and demonstrate for the first time the strong antiproliferative activity of zeaxanthin and β-cryptoxanthin in melanoma cells.

Topics: Antineoplastic Agents; Apoptosis; Breast Neoplasms; Cell Line, Tumor; Cell Proliferation; Cryptoxanthins; Cyanophora; Female; Humans; Lung Neoplasms; MCF-7 Cells; Melanoma; Melanoma, Cutaneous Malignant; Pigments, Biological; Skin Neoplasms; Xanthophylls; Zeaxanthins

Various natural carotenoids were proven to have anticarcinogenic activity. Epidemiological investigations have shown that cancer risk is inversely related to the consumption of green and yellow vegetables and fruits. Since beta-carotene is present in abundance in these vegetables and fruits, it has been investigated extensively as possible cancer preventive agent. However, various carotenoids which co-exist with beta-carotene in vegetables and fruits also have anti-carcinogenic activity. And some of them, such as alpha-carotene, showed higher potency than beta-carotene to suppress experimental carcinogenesis. Thus, we have carried out more extensive studies on cancer preventive activities of natural carotenoids in foods; i.e., lutein, lycopene, zeaxanthin and beta-cryptoxanthin. Analysis of the action mechanism of these natural carotenoids is now in progress, and some interesting results have already obtained; for example, beta-cryptoxanthin was suggested to stimulate the expression of RB gene, an anti-oncogene, and p73 gene, which is known as one of the p53-related genes. Based on these results, multi-carotenoids (mixture of natural carotenoids) seems to be of interest to evaluate its usefulness for practice in human cancer prevention.

Topics: 9,10-Dimethyl-1,2-benzanthracene; Animals; Anticarcinogenic Agents; beta Carotene; Carotenoids; Colonic Neoplasms; Cryptoxanthins; Disease Models, Animal; Fruit; Humans; Lutein; Lycopene; Methylnitrosourea; Mice; Rats; Rats, Inbred F344; Skin Neoplasms; Tetradecanoylphorbol Acetate; Vegetables; Xanthophylls; Zeaxanthins