Antioxidant and xanthine oxidase inhibitory activity of Eucommia ulmoides Oliver leaf extracts.

The total phenolic content, flavonoid content, in vitro xanthine oxidase (XOD) inhibitory activity and antioxidant activity (AA) of Eucommia ulmoides Oliver leaf extracts were investigated. The AA investigations included 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, ß-carotene/linoleic acid bleaching assay and oxygen radical absorbance capacity (ORAC) test. The ethyl acetate fraction (EE) showed the highest AA and xanthine oxidase inhibitory activity. Whilst the lowest 50% inhibition (IC50) value of this fraction for DPPH free radical scavenging was 0.045mg/mL, its highest ORAC value was 10.57 µmol TE/mg. The highest inhibition rate against linoleic acid oxidation observed was 69.41%, and the lowest IC50 value for xanthine oxidase activity inhibition was 2.47mg/mL. These results show that E. ulmoides leaf extract is a promising source of natural antioxidants because it contains high contents of bioactive compounds, including chlorogenic acid, rutin, hyperin and astragalin, as detected by high-performance liquid chromatography coupled to HPLC-DAD-ESI-MS.

Enrichment and purification of gardenia yellow from Gardenia jasminoides var. radicans Makino by column chromatography technique.

In present study, the performance and separation characteristics of nine macroporous resins for the enrichment and purification of gardenia yellow from Gardenia jasminoides var. radicans Makino have been evaluated. The adsorption and desorption properties of crude gardenia yellow solution on macroporous resins including HPD722, HPD100, HPD100A, HPD400, HPD400A, D101, AB-8, XAD-16, and NKA-9 have been compared. Then, HPD722 was chosen to purify gardenia yellow because of its strong adsorption and desorption abilities as well as high selectivity. Column packed with HPD722 resin was used to perform dynamic adsorption and desorption tests to optimize the separation process of gardenia yellow. The optimal conditions were as follows: The crude gardenia yellow solution with concentration of 15 mg/mL was loaded in column packed with HPD722 resin at the flow rate of 1.0 mL/min, and the adsorbate-laden column was washed with 800 mL water, 600 mL 15% ethanol water solution respectively at the speed of 2.5 mL/min, then desorbed with 200 mL 80% ethanol water solution at the speed of 3.5 mL/min. The colority of the product obtained were up to 300. The method developed in this study provides a new approach for scale-up separation and purification of gardenia yellow from G. jasminoides var. radicans Makino.