Chemical composition, antibacterial and antioxidant activity of the essential oil of Bupleurum longiradiatum.

The essential oil from the roots of Bupleurum longiradiatum, obtained by hydro-distillation was analyzed by gas chromatography/mass spectrometry (GC/MS) and evaluated for antimicrobial activity and antioxidant activity. Fifty-one compounds were identified, representing 99.3% of the total oil. The major constituents were thymol (7.0%), butylidene phthalide (6.8%), 5-indolol (5.6%), heptanal (5.3%), 4-hydroxy-2-methylacetophenone (5.3%), 4,5-diethyl-octane (5.3%), bormeol (5.1%) and hexanoic acid (5.1%). The oil was tested against 4 bacteria at different concentrations using disc diffusion and 96-well dilution methods. The inhibition zones and minimum inhibitory concentration values for bacterial strains were in the range of 7.0-18.0 mm and 250 -500 microg/mL, respectively. The in vitro antioxidant activity was assessed by DPPH radical scavenging and inhibition of lipid peroxidation methods. The oil showed a potent free radical scavenging activity, as evidenced by the low IC50 value for DPPH radical (566.2 microg/mL) and inhibition of lipid peroxidation (induced by FeSO4, H2O2 and CCl4) with IC50 values of 275.2 microg/mL, 296.9 microg/mL and 118.7 microg/mL, respectively.