Extracts of Bacopa monnieri (L) Pennell Down-Regulate the Expression of Leukotriene C4 Synthase mRNA in HL-60 Cells and Suppress OVAInduced Inflammation in BALB/c Mice

Aims: To investigate the in vitro and in vivo anti-inflammatory effects of Bacopa monnieri extracts in HL-60 cells and in OVA-induced airway inflammation in BALB/C mice. Materials and Methods: Bacopa monnieri (Brahmi) leaves and stems were collected in Vidisha (M.P.), India, identified and air-dried. The dried plant materials were pulverized to a powder, extracted in methanol to exhaustion, dried and fractionated. The extracts and fractions were tested for their effects on leukotriene C4 synthase, leukotriene A4hydrolase and cyclooxygenase-2 in HL-60 cells. The active dried methanol extract of B. monnieri was then tested in vivo in an OVAinduced asthma mouse model and inflammation was assessed using 2-D imaging. Results: Bacopa monnieri extracts and partitions inhibited leukotriene-C4-synthase, leukotriene-A4-hydrolase and/or cyclooxygenase- 2 (COX-2) activities in cultured HL-60 cells. The EtOAc partition of the extracts inhibited the activity of leukotriene-C4-synthase by 69%, and down-regulated the expression of the mRNA of this enzyme in HL-60 cells. The results demonstrated significant inhibition of leukotriene-C4-synthase, leukotriene-A4-hydrolase and cyclooxygenase-2 (COX-2) activities by the EtOAc fraction of B. monnieri, suggesting a plausible mechanism of action for the management of asthma. Intragastric administration of the B. monnieri extract led to a reduction of OVA-induced lung inflammation as determined by 2-D in vivo imaging using a Xenogen IVIS imaging system. Two compounds were isolated from the active fraction, namely quercetin and isochlorogenic acid A. Conclusions: Extracts of B. monnieri exhibited significant anti-inflammatory effects both in vitro and in vivo, which supported its traditional use for the treatment of inflammatory lung disease and asthma.