采用HPLC结合紫外光谱法, 同时测定四种竹叶黄酮碳苷(荭草苷、 异荭草苷、 牡荆苷和异牡荆苷)。 采用Waters XTerra MS C18色谱柱(250 mm 4.6 mm, 5 μm), 流动相为乙腈和0.5%甲酸水溶液, 等梯度洗脱, 流速1 mL·min-1, 柱温30 ℃, 检测波长360 nm。 建立各个组分在0.1～10.0 mg·L-1范围内系列浓度的混合标准工作曲线, 其相关系数R2均优于0.999, 且在22 min内得到较好分离。 方法检出限介于0.03～0.07 mg·L-1, 定量限介于0.04～0.08 mg·L-1。 分别将标准品与样品中四种黄酮碳苷的紫外光谱(240～400 nm)进行比对, 荭草苷、 异荭草苷、 牡荆苷和异牡荆苷相应的光谱曲线形状以及特征吸收波长都表现出高吻合度。 取竹叶样品经热回流提取, 石油醚萃取及AB-8大孔树脂纯化后, 再采用HPLC结合紫外光谱法检测得荭草苷、 异荭草苷、 牡荆苷和异牡荆苷四种黄酮碳苷相对于竹叶黄酮粉的百分含量分别为13.73, 49.68, 7.85和30.70 mg·g-1, 平均回收率为34.90%～87.64%, 相对标准偏差为0.41%～10.83%。 本方法实现了在较短时间内快速分析竹叶中四种黄酮碳苷, 样品稳定, 重现性好, 为市售竹叶黄酮碳苷的质量控制提供参考。

High-performance liquid chromatography with ultraviolet spectrometer (HPLC-UV) was used to simultaneously detect the four flavone C-glycosides, i.e. orientin, isoorientin, vitexin and isovitexin. Analytes were separated with Waters XTerra MS C18 column (250 mm 4.6 mm, 5 μm) using acetonitrile and 0.5% (φ) formic acid as mobile phase. The flow rate was set at 1.0 mL·min-1 with the column temperature at 30 ℃, and the detection wavelength was 360 nm. The calibration curve was linear over the concentration range of 0.1~10.0 mg·L-1 for the mixed standard solution. Analytes were separated in 22 minutes, and the relative standard deviation values were all above 0.999. LOD values of standards were found to be between 0.03 and 0.07 mg·L-1, and LOQ values were in the range of 0.04~0.08 mg·L-1. After comparing the spectra (240~400 nm) of four flavone C-glycosides in mixed standards and the final product purified by macroporous resin, respectively, the curve shape and characteristic ultraviolet absorption wavelength of each flavone C-glycoside including orientin, isoorientin, vitexin and isovitexin were fitted well. The bamboo leaves sample was extracted by ethanol under reflux, and then partitioned with water and petroleum ether. The aqueous phase was added onto macroporous resin(AB-8), and the fraction of ethanol-water (40%, φ) was concentrated. It was found that the contents of orientin, isoorientin, vitexin and isovitexin relative to the fraction of ethanol-water were 13.73, 49.68, 7.85 and 30.70 mg·g-1, respectively. In addition, the average recovery of the four flavone C-glycosides ranged from 34.90% to 87.64% with RSD values from 0.41% to 10.83%. The results showed that bamboo leaves sample had good stability and repeatability. The new method was used to analyze the four flavone C-glycosides quickly and provide quality control for commercial products.