Antiphotooxidative activity of protoberberines derived from Coptis japonica Makino in the chlorophyll-sensitized photooxidation of oil

Antiphotooxidative components were isolated from the methanolic extract of Coptis japonica Makino by liquid-liquid partitioning fractionation, subsequ ent column chromatography on Sephadex LH-20 and silica gel, and preparative silica gel TLC. The isolated compounds were identified as coptisine, jatro rrizhine, berberine, and magnoflorine by a combination of spectroscopic stu dies using UV-visible, IR, mass-spectrometry, and NMR. Coptisine, jatrorriz hine, and berberine isolated from Coptis japonica Makino showed strong anti photooxidative activity in the chlorophyll-sensitized photooxidation of lin oleic acid. However, these compounds did not show either inhibitory activit y against lipid peroxidation in rat liver microsomes nor DPPH radical scave nging activity, indicating that their antiphotooxidative activity was not d ue to the radical chain reaction breaking ability but due to singlet oxygen quenching activity. Commercially available authentic protoberberines (berb erine chloride and palmatine chloride) also showed strong antioxidative act ivity in the chlorophyll-sensitized photooxidation of linoleic acid. The an tiphotooxidative activities of the berberine chloride and palmatine chlorid e were significantly higher than that of ascorbyl palmitate in the chloroph yll-sensitized photooxidation of linoleic acid. These results clearly showe d for the first time the antiphotooxidative properties of protoberberines i n chlorophyll-sensitized photooxidation of oil.