Antioxidant Activity and Resistance to Food-borne Pathogens from Ligusticum chuanxiong Alcohol Extract

To study the antioxidant activity of Ligusticum chuanxiong alcohol extract(LCAE)and its inhibition to food-borne pathogens. The mainly active components of LCAE were analyzed and their reducing power,total antioxidant capacity even the scavenging effect on hydroxyl radical and superoxide anion were also measured. Adopting duple diluent method and stiletto method have been adopted to study the inhibition of LCAE on 5 common food-born pathogens,the growth trends of the tested bacteria were also studied. The results indicated that the content of TMP,ferulic acid,free phenolic and bound phenolic was 55.7,31.45,177.38 and 42.86 g/kg,respectively. After LCAE diluted 100 times,the reducing power was equivalent to 14.79 μg/mL V_C. The total antioxidant of LCAE was 4.46 U/mg. The clearance rate of 0.9 g/L LCAE on hydroxy radical was 1.12 times of that on superoxide anion. The inhibitory effect of LCAE on gram-negative bacteria was stronger than that of positive bacteria:Salmonella > Escherichia coli > Pseudomonas > Staphylococcus aureus > Bacillus subtilis,and the inhibition in a dose-dependent manner. The MIC were between 6.25~25 g/L while the MBC were lies between 12.5~50 g/L. Inhibitory effect of pure TMP and ferulic acid were lower compared with LCAE at equivalent concentration. Under drug treament,5 tests bacteria growth curve characteristic showed that with the concentration of LCAE increased,the growth of gram-negative test bacteria was significantly inhibited in the logarithmic phase,while the stable phase of positive bacteria was prolonged.