(393i) Isolation and Purification of Natural Antioxidants From Limnophila Aromatica By Using Low-Pressure Column Chromatography of Silica Gel

In recent years, the ingestion of fresh fruits and vegetables rich in natural antioxidants has been associated with the prevention of cancer and cardiovascular diseases. Limnophila aromatica is used as a spice and medicinal herb in Vietnam and Southeast Asia. The aim of this study is to purify and identify antioxidant compounds from defatted L. aromatica by using low-pressure column chromatography of silica gel. Pure ethanol and aqueous ethanol (75% in water) were used for extracting antioxidant compounds in freeze-dried L. aromatica. Crude phenolic extracts were combined and used as raw materials to prepare high purity antioxidants in silica gel column chromatography (400 x 24 mm, 200–300 mesh) with different eluents and elution modes. TLC and DPPH (2, 2-diphenyl-1-pic-rylhydrazyl) were used to check fractions and their antioxidant activities. The purity of each fraction was determined by using HPLC. Six fractions had been obtained by applying sequentially two solvent systems: iso propanol:acetone:ethyl acetate:hexane (10:10:15:65) and methanol:acetone:ethyl acetate:hexane (10:10:25:55) and the purity of those fractions ranges from 27.682% to 96.447%. Nuclear magnetic resonance (NMR), FT-IR, ESI-mass spectrometry and elementary analyzer were used to determine the structure of purity compounds.

The economic and large scale method for isolation and purification of phenolic compounds from defatted L. aromatica had described in our work.