Anti-Salmonella and anti-inflammatory activities of Z-ligustilide from Ligusticum chuanxiong

Ligusticum chuanxiong Hort. (Umbelliferae), a perennial herb cultivated mainly in Korea and China, is one of the main plant sources of Cnidii Rhizoma which were shown to exhibit cardiovascular, antiplatelet, anti-inflammatory, and also antimicrobial and insecticidal effects.

To develop an effective agent against antibiotic-resistant Salmonella infections the essential oil was extracted from the rhizomes of L. chuanxiong and analyzed by GC-MS to identify its composition. The antibacterial activity of the oil fraction and its main components against Salmonella species was estimated using the broth dilution method. Moreover, to determine the combined effect of essential oil components and antibiotics, checkerboard microtiter tests were performed. the fractional inhibiting concentrations (FICs) were calculated. In addition, the anti-inflammatory properties of L. chuanxiong oil and its components evaluated using RAW 264.7. Cell viability was determined by an MTT assay after treatment with various dilutions of the compounds. Inhibition of nitric oxide production in cells treated with lipopolysaccharide (LPS) was evaluated by reaction with Griess reagent. The m-RNA expression levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) were investigated by PCR with corresponding primers and agar gel electrohoresis.

As the results, the minimum inhibiting concentrations (MICs) ranged in value from 1˜>4mg/ml indicating differences between the tested Salmonella species and strains. The L. chuanxiong oil and its components combined with antibiotics showed additive or synergistic activities with FICs between 0.28 and 0.63. The increases of m-RNA expression levels of iNOS and COX-2 were indentified by image analysis of the bands using Gel-doc system.

Keywords: Ligusticum chuanxiong, essential oil, Salmonella, antibiotic-resistant, anti-inflammatory

Acknowledgement: This research was supported by Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education, Science and Technology (2011–0011249)

References: 1) Shin S (2010) Nat Prod Sci 16: 259–264

2) Shin S (2008) Arch Pharm Res 31: 497–502