Medical University of Warsaw, Department of Inorganic and Analytical Chemistry, ul. Banacha 1, 02-091 Warsaw, Poland.
J Pharm Biomed Anal. 2011 Dec 5;56(4):846-50. doi: 10.1016/j.jpba.2011.06.024. Epub 2011 Jul 2.
The objective of this work was to study concentration of silicon and its structural forms present in herbal drugs. Equisetum arvense and Urtica dioica L. from teapot bags, dietary supplements (tablets and capsules) containing those herbs, dry extract obtained from a teapot bag of E. arvense, and samples of the latter herb harvested in wild habitat over four months were studied using wavelength dispersive X-ray spectroscopy (WD-XRF) and high-resolution solid-state (29)Si NMR. The highest concentration of Si, ca. 27mg/g, was found in the herbal material from the teapot bags containing E. arvense. The Si content in natural E. arvense (whole plants) increased from May to August by ca. 7mg/g, reaching value 26mg/g. Three different silicon forms were detected in the studied herbal samples: Si(OSi)4 (Q(4)), Si(OH)(OSi)3 (Q(3)) and Si(OH)2(OSi)2 (Q(2)). Those sites were populated in E. arvense in the following order: Q(4)≫Q(3)>Q(2). A dramatic, ca. 50-fold decrease of the Si concentration during the infusion process was observed. The infusion process and the subsequent drying procedure augmented population of the Q(4) sites at the cost of the Q(2) sites. The WD-XRF and (29)Si NMR methods occurred useful and complementary in the study of herbal materials.
本工作旨在研究草药中硅的浓度及其存在的结构形式。采用波长色散 X 射线荧光光谱法（WD-XRF）和高分辨率固态（29）Si NMR 对来自茶壶袋、含有这些草药的膳食补充剂（片剂和胶囊）、从 E. arvense 的茶壶袋获得的干提取物以及在野生环境中采集的草药样本进行了研究。四个月。在含有 E. arvense 的茶壶袋中的草药材料中发现了最高浓度的 Si，约为 27mg/g。天然 E. arvense（整株植物）中的 Si 含量从 5 月到 8 月增加了约 7mg/g，达到 26mg/g。在研究的草药样本中检测到三种不同的硅形式：Si(OSi)4（Q(4)）、Si(OH)(OSi)3（Q(3)）和 Si(OH)2(OSi)2（Q(2)）。这些位点在 E. arvense 中的存在顺序为：Q(4)≫Q(3)>Q(2)。在浸泡过程中，Si 浓度急剧下降，约为 50 倍。浸泡过程和随后的干燥过程增加了 Q(4)位点的数量，而牺牲了 Q(2)位点。WD-XRF 和（29）Si NMR 方法在草药材料的研究中既有用又互补。
