Flavanols in the nuclei of the tea bush ( Camellia sinensis ) - broadening the perspectives to human health

The nuclei of the tea shrub (Camellia sinensis L.) contain flavanols. Based on the dynamic, fine-tuned subnuclear changes of the flavanol pattern during the cell cycle, it can be postulated that these blue staining phenols play a role in organizing basic mechanisms of chromatin remodelling. Silenced interphase nuclei of mature parenchyma cells indicate a pronounced diffuse distribution of blue stained flavanols using the selective reagent p-dimethylaminocinnam-aldehyde (DMACA). By contrast, in activated nuclei the flavanols reflect a variable, mosaic-like blue patterning enclosed by white interchromatin spaces. Subnuclear expression of euchromatin displays relative tiny blue dots of flavanols as compared with the larger-sized blobs of heterochromatin. From metaphase to telophase, the chromosomes stain a fairly dark blue on flavanols with a more or less diffuse appearance. Those nuclei running through mitotic inter-phases from G 1 to G 2 have well-defined flavanol-free nucleoli. The flavanol pattern of meristematic chromosomes found in the tea plant is basically also valid for herbaceous plants, such as Hyacinthus romanus L., Tulipa gesneriana L. and Allium cepa L., which genuinely do not contain nuclear flavanols. This was verified by incubation of their rootlets in solutions of green tea and epigallocatechin gallate (EGCG). Also human nuclei demonstrate an easy import of added flavanols and the resulting blue stained chromatin reflects in much the same way the structural modifications as already described for the plant nuclei. Flavanols have the potential to associate to the histones of chromatin which inhibits a possible oxidation. Even small fragments of histones can aggregate to catechin as shown on the basis of kinetic measurements for the H4-core peptide HAKRKT and its acetylated product HAK(ac)RK(ac)T.