Essential oil of Ligularia amplexicaulis (wall.) DC found to have antibacterial properties

Researchers from Kumaun University in India isolated and identified the components of the essential oil of Ligularia amplexicaulis, a perennial herb that belongs to the Asteraceae (sunflower) family. The results of their study, which demonstrate the antibacterial activity of L. amplexicaulis essential oil, were published in The Journal of Essential Oil Research.

• The plant L. amplexicaulis grows wild in the Himalayan region of Uttarakhand, India.
• For their study, the researchers isolated essential oil samples from the aerial part of L. amplexicaulis using steam distillation. They analyzed the samples using capillary GC-FID and GC/MS.
• The researchers extracted and analyzed oil samples from plant material collected two different locations (Tungnath and Munsiyari, Uttarakhand, India) separately.
• They reported that the oil samples showed quantitative variation concerning their major constituents.
• They also found that the oil samples were rich in monoterpene hydrocarbons.
• The researchers identified a total of 47 compounds. They listed the following as the major bioactive components:
  • Limonene
  • p-cymene-8-ol
  • a-pinene
  • p-cymene
• The oil samples showed significant antibacterial activity against Gram-negative bacteria, such as Escherichia coli, Agrobacterium tumefaciens, Klebsiella pneumoniae, Xanthomonas phaseoli, Salmonella enterica, and Gram-positive Bacillus subtilis, Staphylococcus aureus, and Enterococcus faecalis.
• Against B. subtilis, S. aureus, E. faecalis, E. coli, A. tumefaciens, and P. multocida, the researchers observed that the minimum inhibitory concentration is 31.25 microliter per milliliter (ul/mL).

Based on their findings, the researchers concluded that the essential oil of L. amplexicaulis is rich in bioactive components that make it a potent antibacterial.

Journal Reference:

Joshi D, Nailwal M, Mohan L, Melkani AB. LIGULARIA AMPLEXICAULIS (WALL.) DC. ESSENTIAL OIL COMPOSITION AND ANTIBACTERIAL ACTIVITY. Journal of Essential Oil Research. 23 January 2018;30(3):189–196. DOI: 10.1080/10412905.2018.1427636