2 research outputs found
Antimycobacterial Labdane Diterpenes from <i>Leucas stelligera</i>
Phytochemical investigation of the
acetone extract of the aerial
parts of <i>Leucas stelligera</i> afforded four new compounds
(<b>1</b>–<b>4</b>) belonging to the labdane diterpene
series as well as two known flavones, velutin (<b>5</b>) and
chrysoeriol (<b>6</b>). Structure elucidation of the new compounds
was carried out using 1D and 2D NMR spectroscopic data and single-crystal
X-ray crystallography of compound <b>1</b>. Compounds <b>1</b>–<b>4</b> exhibited selective antimycobacterial
activity against <i>Mycobacterium tuberculosis</i> with
IC<sub>50</sub> values in the range 5.02–9.80 μg/mL
New pimarane diterpenes and other antimycobacterial metabolites from <i>Anisochilus verticillatus</i>
<div><p>Phytochemical investigation of the acetone extract of the aerial parts of <i>Anisochilus verticillatus</i> afforded a new 8,9-secopimarane diterpene (<b>1</b>), two new isopimarane diterpenes (<b>2</b>, <b>3</b>) and the known ursolic acid (<b>4</b>), α-amyrin (<b>5</b>), β-amyrin (<b>6</b>), stigmast-5-en-3-one (<b>7</b>) and hydroxychavicol (<b>8</b>). Structures of the new compounds were elucidated with the help of 1D and 2D nuclear magnetic resonance spectroscopic data, and single crystal X-ray crystallography of compound <b>3</b>. Compounds <b>2</b> and <b>8</b> inhibited <i>Mycobacterium tuberculosis</i> H37Ra with an IC<sub>50</sub> of 11.3 (IC<sub>90</sub> of 20.0 μg/mL) and 12.5 μg/mL, respectively. Correspondingly, molecular docking studies with Extra Precision Glide revealed a correlation between score and biological activity for these compounds to describe the molecular basis for the most significant SAR results.</p></div