Preparative separation of methylswertianin, swerchirin and decussatin from the Tibetan medicinal plant Swertia mussotii using high-speed counter-current chromatography.

INTRODUCTION: Xanthones, the primary constituents of Swertia mussotii, are known to possess a variety of biological activities, including anti-depressant, anti-leukaemic, anti-tumour, anti-tubercular, choleretic, diuretic, anti-microbial, anti-fungal, anti-inflammatory, anti-viral, cardiotonic and hypoglycemic properties. However, high performance, environmentally friendly methods for isolating and purifying xanthones from S. mussotii are not currently available.
OBJECTIVE: To develop a high performance and environmentally friendly method for the preparative separation of xanthones methylswertianin, swerchirin and decussatin from S. mussotii using high-speed counter-current chromatography (HSCCC).
METHODOLOGY: A solvent system composed of n-hexane:ethyl acatate:methanol:water (5:5:10:4, v/v/v/v) was developed for the separation method. The upper phase was used as the stationary phase, and the lower phase was used as the mobile phase at a flow rate of 1.5 mL/min, a rotation speed of 800 rpm and a temperature of 25 °C.
RESULTS: Using the described method, 8 mg of methylswertianin, 21 mg of swerchirin and 11 mg of decussatin with purities of over 98% could be isolated from a 150 mg crude sample. They were identified by ¹H-NMR and ¹³C-NMR analysis.
CONCLUSION: Three xanthones in Swertia mussotii could be systematically isolated and purified using HSCCC.