Effect of Peganum Harmala Seeds Extract on Nitric Oxide in U937 Monocytes and Macrophages

Nitric oxide (NO) has an important role in inflammation and has been related with pathogenesis and progress of numerous inflammatory- based diseases including some cancers. Peganum harmala is a medicinal plant has been used for treatment of numerous diseases such as several infections. Also anti-inflammatory effects of peganum harmala extracts and its derivatives (harmaline and harmine) by suppressing myeloperoxidase, NO and other mediators have been demonstrated in vivo. In this study, effect of P. harmala seeds aquaeus extract on NO production in U937 monocytic cells and peritoneal macrophages has been evaluated in vitro.

U937 and mice peritoneal macrophages were cultured in RPMI with 10% FBS. Then the cells at logarithmic growth phase were incubated with different concentrations of aqueous extract of P. harmala seeds (0.1 – 1 mg/ml) for 24 hours. Then NO production was assessed by the Griess method in culture medium. Data was analyzed by analysis of variance (ANOVA).

P. harmala seeds aqueous extract did not show any significant effect on LPS-induced NO production in U937 cells and peritoneal macrophages after 24 hours incubation time compared with untreated control cells.

According to results of this study, aqueous extract of P. harmala seeds has no effect on NO production in U937 monocytes cells and peritoneal macrophages. These results suggest that anti-inflammatory effects of P. harmala may be mediated through NO -independent mechanism(s). However further studies to define the P. harmala aqueous extract impact on NO expression in other related normal and cancerous cells are warranted.