A new benzoic acid derivative from Piper diospyrifolium and its anti-Mycobacterium tuberculosis activity

- A new benzoic acid derivative was identified from Piper diospyrifolium.
- Supercritical fluid extraction was employed, using CO2.
- SFE-CO2 extracts and the new compound showed antimycobacterial activity.

The extraction by supercritical fluid (SFE-CO2) from leaves of Piper diospyrifolium and chromatographic column purification afforded the isolation of a new benzoic acid derivative 4-methoxy-3-[(E)-3-methyl-1,3-butadien-1-yl]-5-(3-methyl-2-buten-1-yl)-benzoic acid (1). The chemical structure was elucidated on the basis of spectroscopic methods and comparison with literature data. SFE-CO2 extracts and (1) were tested for their anti-Mycobacterium tuberculosis activities and cytotoxicities in J774G.8 macrophages. The compound (1) and SFE-CO2 extracts exhibited moderate activities against M. tuberculosis H37Rv with minimum inhibitory concentration (MIC) values of 125 μg/mL. The MIC values of M. tuberculosis clinical isolates ranged from 125 μg/mL to >250 μg/mL. The cytotoxicities results showed a selectivity index range from 0.6 to 1.0. Additional studies in structure activity-relationship as well as synergistic activity with antituberculous drugs should be conducted for a better evaluation of anti-mycobacterial activity of this compound.