Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester LE1 9BH, UK.
Leicester School of Pharmacy, De Montfort University, The Gateway, Leicester LE1 9BH, UK.
Spectrochim Acta A Mol Biomol Spectrosc. 2018 Jan 5;188:64-71. doi: 10.1016/j.saa.2017.06.067. Epub 2017 Jul 2.
A new Φ-order kinetic method was proposed in this study for the investigation of trans-cis photoisomerization reaction of Oxyresveratrol (ORVT) subjected to non-isosbestic irradiation. In ethanolic media, it has been proven that forward (Φ) and reverse (Φ) reaction quantum yields were dependent on the monochromatic irradiation wavelength according to sigmoid patterns over the spectral ranges of their electronic absorption (260-360nm). An 11.4- and 6.6-fold increases were recorded for Φ and Φ, respectively. The efficiencies of the former (Φ, ranging between 2.3×10 and 26.3×10) were 33 to 60% smaller than those of the respective Φ measured at the irradiation wavelengths selected. Overall, between 57 and 97% degradation of the initial trans-ORVT was observed under relatively weak light intensities, with the highest values recorded at the longest wavelengths. These findings strongly recommend protection from light in all situations of this biologically important phytomolecule that possesses therapeutic value of interest to pharmaceutical applications. The Φ-order kinetics also offered a simple way to develop a reliable actinometric method that proved ORVT to be an efficient actinometer for the dynamic range 295-360nm. The usefulness of Φ-order kinetics for the investigation and quantification of phytoproducts' photodegradation was discussed.
本研究提出了一种新的Φ阶动力学方法，用于研究在非等色辐照下，氧白藜芦醇（ORVT）的顺反光异构化反应。在乙醇介质中，已经证明正向（Φ）和反向（Φ）反应量子产率与单波长辐照波长有关，根据其电子吸收光谱范围（260-360nm）呈“S”形图案。Φ和Φ分别记录到 11.4 倍和 6.6 倍的增加。前者（Φ，范围在 2.3×10 和 26.3×10 之间）的效率比在选择的辐照波长下测量的各自的Φ小 33%至 60%。总的来说，在相对较弱的光强度下，初始反式 ORVT 降解了 57%至 97%，在最长波长下记录到了最高值。这些发现强烈建议在具有治疗价值并对药物应用感兴趣的这种生物重要植物分子的所有情况下都要避光。Φ阶动力学还提供了一种简单的方法来开发可靠的光化学计量法，证明 ORVT 在 295-360nm 的动态范围内是一种有效的光化学计量法。讨论了Φ阶动力学在研究和量化植物产物光降解方面的用途。
