利用LC/UV/MS比較市售銀杏商品及NIST標準參考物質中帖烯內酯及黃酮醇含量   全文下載

Comparison of the Terpene Lactones and Flavonols Contents in G. Biloba Commercial Samples and the NIST Standard Reference Materials Using LC/UV/MS

對於改善阿茲海默症病人的心智能力，銀杏的葉萃取物有著傳說中的療效。黃酮醇及帖烯內酯被認為是影響人體健康的兩類主要活性物質。幾乎所有的臨床研究證實，銀杏葉的專利萃取物EGb 761R具有功效；因此，大多數的市售銀杏商品也會標示其含量。本論文探討7種市售銀杏商品及3種美國國家標準局（NIST）標準參考物質（SRM 3246 銀杏葉，SRM 3247 銀杏萃取物及SRM 3248 錠狀銀杏）中黃酮醇及帖烯內酯含量。本研究使用梯度逆向高效液相層析法，配合紫外光及質譜儀，檢測銀杏產品之黃酮醇及帖烯內酯含量。定性與定量分析銀杏商品及NIST標準參考物質之甲醇-水（1:1）萃取物的帖烯內酯及黃酮醇。黃酮配醣體的相對組成在不同NIST標準參考物質中具有一致性，卻在不同市售銀杏商品中存有顯著的歧異性。帖烯內酯的相對濃度在不同產品中亦存有顯著差異，但不像黃酮那般明顯。

The leaf extract of Ginkgo biloba has purported value for improving mental capacities in Alzheimer’s patients. The flavonols and the terpene lactones are considered to be the two major groups of active components that influence human health. Almost all the clinical studies regarding G. Biloba were using either EGb 761®, a proprietary extract of G. Biloba leaves, or an extract prepared according to the standard set by it. Consequently, most of the commercial G. Biloba products were labeled with their content accordingly. This paper studied the compositions of both flavonols and terpene lactones of seven commercially available G. Biloba products and three standard reference materials (SRM 3246 G. Biloba leaves, SRM 3247 G. Biloba extract, and SRM 3248 G. Biloba tablet) from the National Institute of Standards and Technology (NIST). In this study, a chromatographic method with UV and mass spectroscopic detection was employed for the determination of the compositions of flavonols and the terpene lactones in Ginkgo products using gradient reversed-phase HPLC. Methanol-water (1:1) extracts of terpene lactones and flavonols out of G. Biloba products and NIST SRMs were analyzed qualitatively and quantitatively. While the relative compositions of the flavonol glycosides were similar for the NIST SRMs, those for the commercial G. Biloba products varied significantly. The relative concentrations of terpene lactones were also shown significant differences among products, but not as dramatic as that of flavonols.