Evaluation of nitric oxide scavenging activity of certain spices in vitro: a preliminary study

The plant extracts of some commonly used spices were examined for their possible regulatory effect on nitric oxide (NO) levels using sodium nitroprusside as a NO donor in vitro. Most of the extracts tested demonstrated direct scavenging of NO and exhibited significant activity and the potency of scavenging activity was in the following order: Foeniculum vulgare (aqueous) > Citrus limettiodes > Murraya koenigii (seed, aqueous) > Murraya koenigii (leaf, aqueous) > Curcuma aromatica (aqueous) > Murraya koenigii (leaf, dichloromethane:methanol) > Mentha arvensis (chloroform) > Mentha arvensis (aqueous) > Curcuma longa > Gingko biloba > Foeniculum vulgare (dichloromethane:methanol) > Zingiber officinale (aqueous) > Curcuma aromatica (ethanolic) > Murraya koenigii (seed, dichloromethane:methanol). All the evaluated extracts exhibited a dose-dependent NO scavenging activity. The aqueous extract of Foeniculum vulgare showed a greatest NO scavenging effect of 79.75% at 62.5 microg/mL as compared to the positive control, Gingko biloba where 36.22% scavenging was observed at similar concentration. The present results suggest that these spices might be potent and novel therapeutic agents for scavenging of NO and the regulation of pathological conditions caused by excessive generation of NO and its oxidation product, peroxynitrite.