Secondary metabolites from the roots of Engelhardia roxburghiana and their antitubercular activities

Engelharquinone (1) engelharquinone epoxide (2), engelharolide (3), and engelhardic acid (4), were isolate and identify for the first time from a plant source together with 20 previously known compounds, four of which were not reported as plant constituents previously. A biological evaluation showed that three of the previously isolated antitubercular constituents [(−)-4-hydroxy-1-tetralone, 3-methoxyjuglone and engelhardione] and engelharquinone (1) exhibited moderate antitubercular activity against Mycobacterium tuberculosis 90-221387.