On the photostability of scytonemin, analogues thereof and their monomeric counterparts
作者:Andreas Ekebergh、Peter Sandin、Jerker Mårtensson
DOI:10.1039/c5pp00215j
日期:2015.12
As a part of their sun-protective strategy, cyanobacteria produce the natural UV-screener scytonemin. Its accumulation in the extracellular sheaths allows the bacteria to thrive in inhospitable locations highly exposed to solar radiation. Scytonemin is often referred to as photostable and has been reported to be non-fluorescent. Taken together, these properties indicate inherently fast non-radiative relaxation processes. Despite these interesting traits, the photophysics of scytonemin is as yet almost completely unexplored. In this study, we have compared the steady-state photophysics of scytonemin itself and four derivatives thereof. Furthermore, the in vitro photostability of scytonemin was studied in different solvents using a solar simulation system. Scytonemin and the investigated derivatives demonstrated a more rapid photoinduced decay in comparison with two commercial UV-screening agents. The photostability could be modulated by varying the solvent, with the protic solvent ethanol providing the most stabilizing environment.
作为蓝藻防晒策略的一部分,蓝藻会产生天然紫外线清除剂 "鞘氨醇"。这种物质在细胞外鞘中的积累使蓝藻能够在太阳辐射强烈的荒凉地区生长。鞘氨醇通常被称为光稳定性物质,据报道它是无荧光的。综合来看,这些特性表明它们本身具有快速的非辐射弛豫过程。尽管具有这些有趣的特性,但迄今为止,人们对 Scytonemin 的光物理几乎完全没有进行过探索。在这项研究中,我们比较了鞘氨醇本身及其四种衍生物的稳态光物理。此外,我们还利用太阳能模拟系统研究了茜草素在不同溶剂中的体外光稳定性。与两种商用紫外线屏蔽剂相比,茜草素及其衍生物的光诱导衰减速度更快。光稳定性可通过改变溶剂来调节,其中原生溶剂乙醇可提供最稳定的环境。