Chromatographic Separation and Determination of Geniposide in Commercial Gardenia Fruit Extract Color

Abstract

Gardenia Fruit (Gardenia jasminoides ELLIS) contains natural colors as well as crocin and crocetin. Recently, several iridoid glucosides (geniposide, gardenoside, etc.) have been reported as constituents of this fruit. Geniposide, a major iridoid component, has been recognized to have a purgative effect in mice.In this work, chromatographic separation and determination of geniposide in commercial gardenia fruit extract color were investigated. Geniposide was analyzed by thin layer chromatography (TLC) on a silica gel plate with a mixture of chloroform-methyl alcohol (4:1) as the developing solvent. The spot on the plate was colored purplish-red when the plate was heated at 100°C for 8min after spraying p-anisaldehyde reagent. The colored spot was determined with a dual-wavelength TLC scanner (measuring wavelength, 500nm; reference, 700nm). The relationship between spot area on the densitogram and the concentration was found to be linear in the concentration range from 100 to 1200ppm (1-12μg/spot) of geniposide (Fig. 2). The detection limit was 300ng of geniposide.High performance liquid chromatography (HPLC) was carried out as follows. Geniposide was determined using a reversed-phase system under the following conditions. Column, Nucleosil 7 C18; eluant, primary water, secondary methyl alcohol (0-100% methyl alcohol linear gradient at 3%/min); detector, 254nm. A linear calibration curve was obtained in the range of 2.8-1, 200ppm (14-6, 000ng/injection) for geniposide (Fig. 3). The minimum detectable amount was 10ng of geniposide.Gardenia fruit (1g) was treated with various solvents and the extracts obtained were analyzed by HPLC. The geniposide content ranged from 53 to 102mg (Table 3). Eighteen samples of commercial gardenia fruit extract color were examined by TLC and HPLC. Geniposide contents in the samples were found to be 0-35.90% (Table 4). These methods are considered to be suitable for the analysis of geniposide in gardenia fruit extracts.