ABSTRACT
To simultaneously determine the contents of p-coumaric acid, chlorogenic acid, 5-caffeoylquinic acid, 4-caffeoylquinic acid, caffeic acid and ferulic acid in Imperatae Rhizoma concentrated granules, an ultra-high performance liquid chromatography (UPLC) with two internal references method (TIRM) was established and validated. Chromatographic separation was achieved on a ZORBAX RRHD Eclipse Plus C18 column (2.1 mm × 100 mm, 1.8 µm) using 1.7 mmol·L-1 oxalic acid in water and methanol as mobile phase. The flow rate was 0.4 mL·min-1 and the column temperature was set as 35 ℃. The relative correction factors (RCFs) of caffeic acid and ferulic acid using p-coumaric acid as internal reference were calculated and the RCFs of 4-caffeoylquinic acid and 5-caffeoylquinic acid were calculated using chlorogenic acid as the internal reference. The TIRM was fully validated for linearity, accuracy, repeatability, stability and recovery so that it could be compared with the external standard method (ESM). The RCFs of 5-caffeoylquinic acid, 4-caffeoylquinic acid, caffeic acid, and ferulic acid were 1.069, 1.022, 1.368, and 1.493, respectively. The TIRM and ESM were used to determine the contents of six ingredients in Imperatae Rhizoma concentrated granules from different manufacturers and the variation between results was within acceptable limits. In conclusion, the newly established TIRM allowed simultaneous determination of six ingredients (p-coumaric acid, chlorogenic acid, 5-caffeoylquinic acid, 4-caffeoylquinic acid, caffeic acid, ferulic acid) in Imperatae Rhizoma concentrated granules, providing support for the quality control of this traditional Chinese medicine.
ABSTRACT
The violanthin, a specific component, was separated and identified from the stems of Dendrobium officinale by chromatographic technique and spectroscopic method for the first time. The microscopic characteristics of D. officinale powder were examined under a microscopy and described. Thin layer chromatography (TLC) method was used for qualitative analysis of the violanthin from D. officinale stems with a mixture of ethyl acetate, butanone, formic acid and water (4∶3∶1∶1) as the developing solvent on high performance silica gel precoated plate (SGF254) and using aluminium trichloride as a chromagenic agent. The results showed significant characteristics of violanthin from D. officinale stems on TLC, with certain specificity, and could be used to distinguish it from other easily confusing processed medicinal stems of D. devonianum, D. gratiosissimum and D. aphyllum. The content of naringenin, an active ingredient in D. officinale stems was determined by HPLC analysis on a Bischoff Chromatography HIPAK NC-04 ODS AB column (4.4 mm×250 mm, 5 mm) with acetonitrile-0.1% phosphoric acid solution as the mobile phase for gradient elution. The wavelength was set at 226 nm and column temperature was 25 ℃. The HPLC method showed good linearity within the range of 3.90-250.00 g•mL⁻¹ (r = 0.999 9) for naringenin. The average recovery of naringenin was 99.20% with 0.17% of RSD. The mass fraction of 20 batches of D. officinale stems was between 0.190 and 0.498 mg•g⁻¹. The established qualitative and quantitative method was simple and rapid with good repeatability and accuracy, providing experimental basis for improving the quality standard of D. officinale, with a very important significance to ensure its quality and clinical effect.