No abstract

Stabilities of anthocyanins from Concord grapes, red cabbage, tradescantia and ajuga were studied. RP-HPLC analysis was used to characterize individual anthocyanins and spectrophotometric analysis for all pigments. Anthocyanins from tradescantia were much more stable than the other extracts. Such increased stability was attributed to its intrinsic nature.

Expression of anthocyanins and other flavonoids in callus cultures established from different parts of cranberry plant was investigated and the effect of explant source on the in vitro product was determined. Callus cultures were initiated from different parts of the plant in a modified Gamborg's medium with 5.37 pM o-naphthaleneacetic acid, 0.45 pM 2,4-dichlorophenoxyacetic acid, and 2.32 pM kinetin in the dark at 25°C. Callus cultures accumulated anthocyanins only on exposure to light and maximum concentration was observed by day 12. The cultures had lower levels of anthocyanins and only cyanidin 3-galactoside, cyanidin 3-glucoside, and cyanidin 3-arabinoside were identified in all cultures regardless of source of explant. Proanthocyanidin accumulation in cultures was independent of light, and levels were higher than in mature fruit. Exposure to light induced accumulation of flavonols and enhanced activity of phenylalanine ammonia-lyase in the cultures.

The anthocyanins from Ajuga pyramidalis Metallica Crispa cell cultures were characterized by a combination of HPLC, chemical hydrolysis, MS, and 1H NMR. Chromatographic analysis of the in vivo and in vitro samples showed the same suite of anthocyanins and relative composition. Chemical hydrolysis and mass spectral analysis of the major pigment from suspension cultures showed the presence of cyanidin, three glucoses, two ferulic acids, and malonic acid. The structure of the major pigment in the suspension cultures was determined to be 3-O-(6-O(E)-ferulyl)-2-O-[(6-O(E)-ferulyl)-β-d-glucopyranosyl-β-d-glucopyranosyl]-5-O-(6-O-malonyl)-β-d-glucopyranosylcyanidin. The anthocyanins in the in vitro extract were more stable toward light compared to those in the in vivo extract. The initial degradation of the major pigment both from in vitro and in vivo sources was mainly due to demalonylation. Keywords: Ajuga; anthocyanins; cell culture; stability-anthocyanins