Separation of nine novel triterpene saponins from Camellia japonica seeds using high-performance countercurrent chromatography and reversed-phase high-performance liquid chromatography.

ABSTRACT

INTRODUCTION: Camellia japonica L. (Theaceae) is an evergreen shrub, which is cultivated as a popular ornamental tree in Korea, China, and Japan and its seeds have been used as a source of cooking oil, in cosmetics and as a traditional medicine. Intensive phytochemical works have revealed that oleanane-type saponins are the characteristic compounds of the seeds of C. japonica. OBJECTIVE: The purpose of the present study is to isolate and determine oleanane-type saponins from C. japonica using high-performance countercurrent chromatography (HPCCC) coupled with reversed-phase high-performance liquid chromatography (RP-HPLC) and spectroscopic evidences, respectively. METHODOLOGY: HPLC electrospray ionisation quadrupole time-of-flight mass spectrometry (ESI-Q-TOF-MS) was applied to profile the saponin composition of an enriched saponin extract of C. japonica seeds. The enriched saponin extract was separated by HPCCC using a dichloromethane/methanol/isopropanol/water (9614, v/v/v/v) system and RP-HPLC. The structures of the isolates were determined utilising ESI-Q-TOF-MS, one-dimensional and two-dimensional NMR and optical rotation. RESULTS: HPCCC on enriched saponin extract of C. japonica yielded four saponin fractions in the order of the number of sugars attached to the triterpene aglycone, and preparative RP-HPLC on each saponin fraction led to the isolation of nine novel saponins, namely camoreoside A-I, along with six known ones. CONCLUSIONS: This study indicates that combination of HPLC-ESI-Q-TOF-MS analysis and HPCCC coupled with RP-HPLC are excellent tools for discovering saponins from natural sources.