Studies On Antimicrobial Activities And Scavenging Free Radicals Of Extracts From Inula Cappa

This study evaluated the antimicrobial activity and antioxidant potential of extracts of Inula cappa in order to provide scientific proof for its wide application in traditional medicine system. Extraction of whole roots, stems and leaves of I. cappa using organic solvents of increasing polarity and water, respectively, were obtained. The extracts were tested for their in vitro antimicrobial properties by using a disk-diffusion and serial two-fold dilutions method. The effects of different concentrations of I. cappa extracts on viability of Staphylococcus aureus and Salmonella paratyphi A were investigated completly for various time exposures, and the antimicrobial activity of I. cappa against the microorganisms was determined at different pH. The extraction technology of flavonoids in the I. cappa leaves was studied according to the orthogonal design. The essential oils extracted from I. cappa by steam distillation were analyzed by GC-MS. The antioxidative activities of the oil were evaluated using Fenton reaction assay and Pyrogallol autoxidation method. All of the plant extracts tested displayed clearlly a stronger and broader spectrum of antibacterial activity. The time-killing curves and concentration-killing curves indicated that the plant extracts could be a time-dependent for Staphylococcus aureus, and a concentration-dependent for Salmonella paratyphi A. Optimum pH values of the extracts of I. cappa actived against Salmonella paratyphi A are 6-8. The extraction technology also showed that the processing conditions affected the yield, and that the effect of each condition decreased in the following order: extracting ethanol concentration, extracting time, in proportion of extracting solvents. 25:1 of 70% ethanol to the bud of sophorajaponica weigh ratio was used with ultrasonic treatment for 3h once at the temperature of 60℃. The results showed that twenty-eight components were identified in the oil, and three main compounds of the oil were Phenol, 3-methyl-5-[1-methylethyl]-, methylcarbamate(74.37%), 11,14-eicosadienoic acid, methyl ester(9.50%), Propanoic acid, 2, 2-dimethyl-, 2-[1,1-dimethylethyl]phenylester (7. 59%). The antioxidative activities of the oil were evaluated using Fenton reaction assay and Pyrogallol autoxidation method. These results showed that the oil could scavenge both the superoxide (o2(?)-) radical and the hydroxyl radical, and the scavenging OH’ ability of the oil was better than that of scavenging the superoxide (O2(?)-)radical. This in vitro study corroborated the antimicrobial activity of the selected plants used in folkloric medicine and also showed that I. Cappa DC. could be potential sources of new antimicrobial agents.