Murai Yoshinori, Setoguchi Hiroaki, Kitajima Junichi, Iwashina Tsukasa
Nat Prod Commun. 2015 Mar;10(3):407-11.
Ultraviolet-B radiation is harmful to plants, and its intensity increases at altitude. So plants growing at high altitude possess UV protection systems. Flavonoid is known as a major UV protectant because it absorbs UV radiation and scavenges UV-induced free radicals in plant tissues. Japanese knotweed (Fallopia japonica) and Japanese larch (Larix kaempferi) grow at a wide range of altitudes on Mt. Fuji, the highest mountain in Japan, while the two plants harbor a homogeneous genetic structure. In the present study, a total of 14 flavonol 3-O-glycosides were isolated from both species. Furthermore, quantitative HPLC analyses revealed that flavonoid levels in the leaves of F. japonica and the needles of L. kaempferi increased with increasing altitude of their growing sites. The altitudinal trend of UV-absorbing antioxidants of herbal and woody plants was simultaneously revealed for the first time. These results suggest that both species have chemically acclimatized to high altitude regions, in which severe environmental conditions such as higher UV radiation exist.
紫外线B辐射对植物有害，且其强度会随海拔升高而增加。因此，生长在高海拔地区的植物拥有紫外线防护系统。黄酮类化合物被认为是主要的紫外线防护剂，因为它能吸收紫外线辐射并清除植物组织中紫外线诱导产生的自由基。虎杖（Fallopia japonica）和日本落叶松（Larix kaempferi）生长在日本最高峰富士山的广泛海拔区域，而这两种植物具有相同的遗传结构。在本研究中，从这两个物种中总共分离出了14种黄酮醇3-O-糖苷。此外，定量高效液相色谱分析表明，虎杖叶片和日本落叶松针叶中的黄酮类化合物含量随着其生长地点海拔的升高而增加。草本植物和木本植物吸收紫外线的抗氧化剂的海拔变化趋势首次同时得到揭示。这些结果表明，这两个物种在化学上都适应了高海拔地区，那里存在诸如更强紫外线辐射等恶劣环境条件。
