FLAVONOIDS AS UV-PROTECTANT

Authors:	K. Takeda, Y. Tochika, R. Fukazawa, T. Mori
Abstract: Using the seedlings of Solanum melongena, which were grown under UV-B (300–390 nm) illumination (+UV) or a UV-B free condition (-UV), we examined the role of flavonoid compounds as UV-protectand. UV-B illumination had no significant effect on chlorophyll content in the cotyledons, however remarkably increased flavonoid content. Flavonoid compounds were accumulated mainly in epidermal and palisade mesophyll cells. +UV seedlings accumulated with flavonoids were resistant to UV irradiation. In contrast, - UV seedlings were sensitive to UV. Furthermore, to reveal the role of flavonoids as UV protectant, the levels of DNA damage of the cotyledons were examined immediately after UV irradiation, using monoclonal antibodies specific for cyclobutane dimer and for (6–4) photoproduct. As a result, both types of photoproducts were detected in DNA from UV irradiated +UV and -UV cotyledons. However, damage levels in DNA of +UV seedlings were clearly lower than those in DNA of -UV seedlings. The results show that flavonoids play a role as UV protectant.
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