Effect of baicalein and acetone extract of Scutellaria baicalensis on canola oil oxidation

There is an increasing interest in natural antioxidants present:in traditional Chinese herbal medicines. The present study examined the antioxidant activity of hexane, acetone, and methanol extracts, as well as baicalein purified from the dry roots of Scutellaria baicalensis Georgi (common name: Huangqin), in heated canola oil. Oxygen consumption and decreases in linoleic and linolenic acid content were monitored in canola oil held at 90-93 degrees C. Among the three extracts, the acetone extract was most effective against oxidation of canola oil, followed by the methanol extract of the dry roots. The antioxidant activity of these three extracts correlated well with their content of baicalein, which provided strong protection to canola oil from oxidation. The antioxidant activity of Huangqin acetone extract was dose-dependent. The acetone extract at 100 ppm or above was even more effective than butylated hy droxytoluene at 200 ppm in protecting canola oil from oxidation. The present results suggest that the acetone extract of these roots should be further explored as a potential source of natural antioxidants for use in the processed foods.