Studies On Antioxidant Activites Of Barley And Malt Extract

In the passed 20 years, studies on reactive oxygen species (ROS) and free radicals have become the hot topics and appraisal of modern life science.The evaluation and selection of natural resources with strong antioxidative activities have become the new trends of biology, medical science and food science and technology. Both experimental and epidemiological studies have demonstrated that cereals, vegetables, and fruits contain a myriad of phenolic compounds with high antioxidative activity. These phenolic compounds include flavonoids, phenolic acids, diterpenes and tannins. Barley is a widely consumed cereal among the most ancient cereal crops, but nearly 80-90% are used for animal feeds and malt production. Malt, as the production of the barley fermentation, is used for the manufacturing of beer. Recently, there are growing interests in barley and malt because of their high content of phenolic compounds.The present study evaluated the antioxidant activity of barley and malt extract in vitro and in vivo. Taking acetone as extraction solvent, the present study first obtained extracts from the barley and malt and by employing ultrasonic extraction method. Then the total phenolics contents of extracts were examined. We set out to determine the antioxidant properties of malt in vitro, by measuring scavenging effects on the hydroxyl radical and superoxide radical, reducing power, inhibition of lipid peroxidation, protein carbonlytaion and DNA damage. We then evaluated the potential antioxidant potential of malt in vivo, in the D-galactose induced mouse aging model. The results are as follows:(1).The present study used acetone as our extraction solvent and obtained a 7.425% yield of extracted materials from malt and 4.325% from barely. After the ultraviolet and infrared spectra analysis of the components of the extracts, the researcher found that they both contained a large number of phenolic compounds, and the total phenolic content in malt extract (143.9 mg/g) are higher in barley (86.1 mg/g). After a comprehensive analysis of the yield of extracts and the contents of the phenolic compounds in the extract, the present study found that the content of phenolic compounds in barley and malt is basically the same.(2).Barley and malt extract exhibited high scavenging effects on the hydroxyl radical and superoxide radical, and barely extract was more efficient than malt extract. When the concentration is 115 and 1500μg/ml, the percentage scavenging of barely extract for hydroxyl radical and superoxide radical is 50%. Malt extract at 117μg/ml the percentage scavenging for hydroxyl radical is 50%, and at 1500μg/ml the percentage scavenging for superoxide radical is 47.1%. Meanwhile, the scavenging ability of barley and malt was stronger than Trolox. Barley and malt extract have strong reducing power, which was basically consistent with Trolox.(3).The extracts from barley and malt was effective for the prevention of oxidative damage on biological macromoleculars. The effect of the extract in barley was slightly stronger than the extract in malt. The IC50 of inhibit lipid peroxidation in the extract of barley and malt were respectively 125μg/ml and 231μg/ml. Barley and malt extract exhibited not a very strong protective effect against oxidation of protein. Barley extract at 250μg/ml the protection rate for the degradation of BSA was 67%, and at 500μg/ml the protection rate of malt extract was 65%, and the protective effect of both was weaker than Trolox. Barley and malt extract in low concentration (31.625μg/ml) significantly protected the DNA oxidation. At 250μg/ml, both of them completely protected the oxidation of DNA. Moreover, the effect of the extract in barley and malt was the same as in Trolox.(4).The D-galactose induced mouse aging model was used to evaluate ability of antioxidant of malt extract in vivo. Malt extract could effectively enhance the defense capability of the antioxidant defense system with medium-dose (200 mg/kg) and high-dose (400 mg/kg). Compared to the aging model group, each index in malt extract treatment group were obviously improved. In comparison to aging model group, at dose of 200 and 400 mg/kg, the total anti-oxidant capability increased by 25.1% and 53.2% in blood, the SOD activity increased by 31% and 42.3% in brain, the MAO activity decreased by 11.5% and 23.6% in brain, MDA levels declined by 37.3% and 48.3% in brain, and the SOD activity increased by 36.4% and 43% in liver, the MAO activity decreased by 14.7% and 27.4% in liver, MDA levels declined by 37.9% and 48.3% in liver. Meanwhile, malt extract significantly increased the activity of GSH-Px and decreased the content of carbonyl in aging brain and liver.