No abstract

Crocin-a water soluble carotenoid-is found in the fruits of gardenia (Gardenia jasminoides Ellis) and in the stigmas of saffron (Crocus sativus Linne). For crocin purification, gardenia fruits are extracted with 50% acetone, followed by ether washing, ion exchange, and separation by preparative HPLC. Purified crocin with purity of >99.6% has an antioxidative activity at concentrations up to 40 ppm. At 20 ppm the antioxidative activity of crocin is comparable to that of BHA. The antioxidant property of crocin as evaluated by the thiocyanate method was better than with the thiobarbituric acid method. The adduct between the linoleic acid radical and crocin was detected by LC-MS. When crocin reacted with oxygen in the presence of FeSO(4), intermediates such as monohydroperoxides and dihydroperoxides of crocin were formed and detected by LC-MS.

No abstract

A cell suspension of grape, Vitis vinifera L. cv Gamay Fréaux, was grown under different conditions of water stress (high external osmotic potential) induced by an increase of sucrose concentration or by the addition of mannitol to the culture medium. Best growth (cell density) was achieved in the low osmotic potential medium. Increasing the osmotic potential of the medium from -0.5 MPa to -0.9 MPa medium resulted in a significant increase in accumulation of anthocyanins in pigmented cells. Regulation of the osmotic potential of culture medium may be useful in controlling anthocyanin production.

A cell suspension of Vitis vinifera L. cv. Gamay Frédaux var. teinturier composed of 50% pigmented cells was grown in Gamborg B5 medium supplemented with (per litre) 250 mg casein hydrolysate, 0.1 mg α-naphthalenacetic acid, 0.2 mg kinetin, and either 20, 30, 50, or 60 g sucrose. In the presence of 20 and 30 g sucrose/L, growth of cells was characterized by a typical sigmoid pattern and maximum cell density was obtained in 30 g sucrose/L. In both media, the anthocyanin content of pigmented cells did not change significantly throughout the growth cycle. In the presence of 50 g sucrose/L, cell growth was characterized by an extended lag phase. During this period, there was a significant (P < 0.05) accumulation of anthocyanins in the pigmented cells. Browning of the medium and premature cell death was observed in medium with 60 g sucrose/L. Microscopic observation of the suspension revealed the occurrence of anthocyanoplasts, especially in anthocyanin-containing cells cultured in 50 g sucrose/L. In some instances anthocyanoplasts were observed in cells with nonpigmented vacuoles, thus supporting the thesis according to which anthocyanoplasts would be the site of anthocyanin synthesis. Key words: anthocyanins, anthocyanoplasts, cell culture, metabolism, sucrose, Vitis vinifera.