Chemical Composition and Biological Activities of Essential Oils of Four Asarum Species Growing in Vietnam

The essential oils (EOs) of the aerial parts of four Asarum species (A. geophilum, A. yentunensis, A. splendens and A. cordifolium) were isolated by steam distillation and analyzed by the GC/MS method. The A. cordifolium EO contains 33 constituents with the main component being elemicine (77.20%). The A. geophilum EO was contains 49 constituents with the main components being determined as 9-epi-(E)-caryophyllene (18.43%), eudesm-7(11)-en-4-ol (13.41%), β-caryophyllene (8.05%) and phytol (7.23%). The A. yentunensis EO contains 26 constituents with the main components being safrole (64.74%) and sesquicineole (15.34%). The EO of A. splendens contains 41 constituents with the main components being 9-epi-(E)-caryophyllene (15.76%), eudesm-7(11)-en-4-ol (14.21%), β-caryophyllene (9.52%) and trans-bicyclogermacrene (7.50%). For antimicrobial activity, the A. yentunensis EO exhibited the highest inhibition activity against Staphylococcus aureus and the A. cordifolium EO against Bacillus subtillis (MIC values of 100 μg/mL). For antioxidant activity, the A. geophilum EO showed the highest potential with an SC (%) value of 63.34 ± 1.0%, corresponding to an SC(50) value of 28.57 µg/mL. For anti-inflammatory activity, the A. splendens EO exhibited the highest potential with an IC(50) value of 21.68 µg/mL, corresponding to an inhibition rate of NO production of 69.58 ± 1.3% and the percentage of cell life was 81.85 ± 0.9%.