[Determination of Total Sulfur Dioxide in Chinese Herbal Medicines via Triple Quadrupole Inductively Coupled Plasma Mass Spectrometry].

As an important treatment method, sulfur fumigation plays an essential role in the production and preservation of traditional Chinese herbal medicines. Although there is strict regulation on the use of sulfur dioxide, the abuse of sulfur dioxide still occurred from time to time. And the public faces a high risk of exposure. Because of the poor precision and tedious preparation procedures of traditional recommended titration, the accurate and convenient determination of sulfur dioxide in Chinese herbal medicines is still a critical analytical task for medicines safety and the public health. In this study, an accurate, high-throughput, and convenient method for the absolute determination of SO2 in Chinese herbal medicines based on triple quadrupole inductively coupled plasma mass spectrometry (ICP-MS/MS) technique is developed. The study compared the quantitative ability for sulfur when the ICP-MS operated under traditional single quadrupole (QMS) mode and novel triple quadrupole (MS/MS) mode with three Reaction/Collision cell condition (no gas, helium, and oxygen). The result indicated that when the concentration of sulfate ranging from 0.5 to 100 mg · L⁻¹, isotopic ³4S can be selected as quantitative ion either the ICP-MS operated under the QMS mode or MS/MS mode. The use of helium in the Reaction/Collision cell decreased the single intensity of background ions. Better than QMS mode, the MS/MS mode can effectively reduced background interference. But there are no significant differences about the linear range and limit of detection. However, when the ICP-MS operated under MS/MS mode and oxygen was used as reaction gas in the Reaction/Collision cell, the ICP-MS/MS provided an interference-free performance, the linear range and limit of detection improved significantly. Either ³²S or ³4S exhibits an excellent linearity (r > 0.999) over the concentration range of 0.02-100 mg · L⁻¹, with a limit of detection of 5.48 and 9.76 µg · L⁻¹ for ³²S¹6O4²â» and ³4S¹6O4²â», respectively. The Chinese herbal medicines was treated using microwave digestion added 6 mL nitric acid and 2 mL hydrogen peroxide before analysis. The amount of nitric acid and hydrogen peroxide were optimized. The method was validated using Chinese herbal standard reference material GBW10020. The sample was treated and detected in six parallel, and the average concentrations obtained using the developed method (0.42% ± 0.01%) is in excellent agreement with the standard concentration (0.41%± 0.03%). The study demonstrates an accurate and convenient approach for the quantification of SO2 in Chinese herbal medicines.

[Inhibitory effects of Scutellaria barbatae D. Don on tumor angiogenesis and its mechanism].

BACKGROUND & OBJECTIVE: Various chemically synthetic anti-angiogenesis agents have serious side effects. The traditional Chinese medicine has attracted considerable attention because of its low toxicity. This study was to explore the inhibitory effects of Scutellaria barbatae D. Don, a kind of traditional Chinese medicinal anti-cancer herb, on tumor angiogenesis, and investigate its mechanism. METHODS: Matrigel plug and human umbilical vascular endothelial cells (HUVECs) were used to construct in vivo and in vitro models of angiogenesis to assess the effect of Scutellaria barbatae D. Don on angiogenesis. After cultured with Scutellaria barbatae D. Don, the migration of endothelial cells was examined by Transwell chamber; the expression of vascular endothelial growth factor (VEGF) in HeLa cells was detected by enzyme-linked immunosorbent assay (ELISA). RESULTS: Scutellaria barbatae D. Don significantly inhibited angiogenesis in Matrigel; the tube formation number was significantly lower in 20% and 40% medicated serum groups containing Scutellaria barbatae D. Don than in 20% and 40% drug-free serum groups (5.6+/-1.1 vs. 9.8+/-1.3, P=0.001; 1.0+/-0.7 vs. 13.4+/-1.1, P<0.001). Migrated endothelial cells was significantly fewer in 20% and 40% medicated serum groups containing Scutellaria barbatae D. Don than in 20% and 40% drug-free serum groups (19.75+/-2.63 vs. 24.25+/-2.06, P=0.038; 14.00+/-2.58 vs. 26.5+/-4.65, P=0.006). When treated for 24 h and 48 h, the expression of VEGF in HeLa cells was significantly lower in 40% medicated serum group containing Scutellaria barbatae D. Don than in 40% drug-free serum group (138.67+/-9.50 vs. 195.82+/-2.43, P=0.006; 93.84+/-41.11 vs. 193.68+/-18.37, P=0.036). CONCLUSION: Scutellaria barbatae D. Don could efficiently inhibit angiogenesis in tumor tissue which might relate with inhibition of endothelial cell migration and down-regulation of VEGF in tumor cells.