https://doi.org/10.3390/separations9120446
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To generate the mixed standard curve, a total of 10 mg of paclitaxel and 10-DAT standard were accurately weighed and dissolved in methanol to a constant volume of 10 mL. Then, the samples were diluted with methanol to prepare solutions with different concentration gradients. The peak areas of standard solutions with different concentrations were measured by HPLC at 227 nm, and the high-performance liquid standard curves of two standards were drawn with the peak area as the ordinate and the standard concentration as the abscissa. The concentrations of two taxanes were calculated using the calibration curves (the concentration range of the calibration curves was 1.25–125 μg/mL). The total yields of the two main taxanes of Taxus cuspidata were calculated as follows:
where C (μg/mL) is the total content of two main taxanes, V (mL) is the volume of extraction solution recovered, and W (g) is the weight of Taxus cuspidata.
2.4. Purification Experiment of Preparative HPLC
Preparative HPLC [58] (Hanbon Sci&Tech, Hangzhou, China) was used to collect two taxanes in Taxus cuspidata extract. The gradient elution procedure was set as follows: Hedera ODS-2 C18 column (250 mm × 20 mm, 5 μm, detection wavelength 227 nm). Then, according to the experimental scheme (single-factor and orthogonal experiments scheme), the parameters were set, including flow rate, injection volume, and column temperature. Mobile phase A was purified water and B was acetonitrile. Gradient elution procedure: B increased from 40% to 50% at 0–10 min, and B increased from 50% to 53% at 10–13 min. B increased from 53% to 73% at 13–25 min, and at 25–30 min, B decreased from 73% to 40% for 10 min.
2.5. Single-Factor Experiments
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