Antimycobacterials from Lovage Root (Ligusticum officinale Koch)

The n‐hexane extract of Lovage root was found to significantly inhibit the growth of both Mycobacterium smegmatis mc2155 and Mycobacterium bovis BCG, and therefore a bioassay‐guided isolation strategy was undertaken. (Z)‐Ligustilide, (Z)‐3‐butylidenephthalide, (E)‐3‐butylidenephthalide, 3‐butylphthalide, α‐prethapsenol, falcarindiol, levistolide A, psoralen and bergapten were isolated by chromatographic techniques, characterized by NMR spectroscopy and MS, and evaluated for their growth inhibition activity against Mycobacterium tuberculosis H37Rv using the whole‐cell phenotypic spot culture growth inhibition assay (SPOTi). Cytotoxicity against RAW 264.7 murine macrophage cells was employed for assessing their degree of selectivity. Falcarindiol was the most potent compound with a minimum inhibitory concentration (MIC) value of 20 mg/L against the virulent H37Rv strain; however, it was found to be cytotoxic with a half‐growth inhibitory concentration (GIC50) in the same order of magnitude (SI