Neurosedative and antioxidant activities of phenylpropanoids from Ballota nigra

Ballota nigra is a European plant known for its neurosedative properties. I n this study the ability of five phenylpropanoids (verbascoside, forsythosi de B, arenarioside, ballotetroside. and caffeoyl malic acid) isolated from a hydroalcoholic extract, to bind to benzodiazepine, dopaminergic, and morp hinic receptors was investigated. To carry out these studies, affinity test s with rat striata, entire brains and receptor rich preparations were emplo yed. In addition, the phenolic aspect of these five phenylpropanoid esters led to investigate antioxidant activities using cell-free experiments and c ellular experiments including isolated polymorphonuclear neutrophils (PMN). Effects of phenylpropanoid esters against reactive oxygen species as super oxide anion. peroxide hydrogen, hypochlorous acid and hydroxyl radical were tested. These molecules are liberated by PMN during inflammatory disorders , so that reproduction of this process in vitro stimulating PMN by chemical stimulants was undertaken. Results show that four of the five compounds are able to bind to the studie d receptors. Inhibitory concentrations at 50 % were determined and vary fr om 0.4 to 4.7 mg/ml. This may be in relation with the Ballota nigra known n eurosedative activities. Results concerning antioxidant investigations evid ence all ability to scavenge reactive oxygen species. Inhibitory concentrat ions at 50 % obtained are comparable to those of known antioxidant drugs (m esna or N-acetyl cysteine). Moreover, the use of different stimuli having v arious pathways of action on PMN oxidative metabolism permits to establish that each phenylpropanoid ester has its own particular way of action by usi ng proteine kinase C or phospholipase C pathways.