Simultaneous separation and determination of seven biphenyl cyclooctene lignans in Schisandra chinensis and its preparations by micellar electrokinetic chromatography with dual organic solvent system

Introduction: Gomisin is a natural dibenzo cyclooctene lignan, which is mainly derived from the family Magnoliaceae. It has anti-inflammatory, antioxidant, anti-tumor, anti-aging, and hypoglycemic effects. Gomisins play important roles as medicines, nutraceuticals, food additives, and cosmetics.

Objective: The objective of this study is to establish a micellar electrokinetic chromatography (MEKC) method for simultaneous separation and determination of seven biphenyl cyclooctene lignans (Gomisin D, E, G, H, J, N, and O) in Schisandra chinensis and its preparations.

Methods: The method was optimized by studying the effects of the main parameters on the separation. The method has been validated and successfully applied to the determination of seven Gomisins in S. chinensis and its preparations.

Results: In the separation system, the running buffer was composed of 20 mM Na₂HPO₄, 8.0 mM sodium dodecyl sulfate (SDS), 11% (v/v) methanol, and 6.0% (v/v) ethanol. A diode array detector was used with a detection wavelength of 230 nm, a separation voltage of 17 kV, and an operating temperature of 25°C. Under this condition, the seven analytes were separated at baseline within 20 min, and a good linear relationship was obtained with correlation coefficient ranging from 0.9919 to 0.9992. The limit of detection (LOD, S/N = 3) and the limit of quantification (LOQ, S/N = 10) ranged from 0.8 to 0.9 μg/mL and from 2.6 to 3.0 μg/mL, respectively. The recovery rate was between 99.1% and 102.5%.

Conclusion: The experimental results indicated that this method is suitable for the separation and determination of seven Schisandra biphenyl cyclooctene lignan compounds in real samples. At the same time, it provides an effective reference for the quality control of S. chinensis and its preparations.