10.22376/ijpbs.2019.10.1.p1-12 Volume 3 Issue 4 2012(October - December) lessThan i greaterThan Salvadora persica ( lessThan /i greaterThan Salvadoraceae) is widely used in Unani system of medicine. Its root and stem were extracted using solvents of different polarities and explored for lessThan i greaterThan in-vitro lessThan /i greaterThan free radical scavenging activity and lipid per-oxidation assay in rat brain homogenate. Preliminary assays of six different extracts of lessThan i greaterThan Salvadora persica lessThan /i greaterThan , scavenges 1,1-diphenyl-2-picrylhydrazyl stable free radicals in concentration dependent manner. All studied extracts possess electron donating ability and reduce ferric ion to ferrous in a cell free system at pH-7.4. Also, 250 and 500µg/ml alcoholic and hydro alcoholic extracts reduced the activated lipid per-oxidation in rat brain homogenate. Further, both extracts reduced the lipid per-oxidation to the extended time period (1 to 12 hour after initiation of lipid per-oxidation). Root extracts were found more effective when compared to stem in scavenging 1,1-diphenyl-2-picrylhydrazyl, reducing ferric ion and inhibiting the lipid per-oxidation. Hydro-alcoholic extracts were found more effective in scavenging the 1,1-diphenyl-2-picrylhydrazyl and reducing the ferric ions. The significant correlations exist between extract concentrations and percentage scavenging activity of radicals in all models. These results clearly indicate that lessThan i greaterThan Salvadora persica lessThan /i greaterThan is effective free radical scavenger and chain breaking antioxidant. MANGAL SAIN HOODA AND JANARDHAN SINGH Antioxidant, DPPH, Free Radical Scavenging, Miswak, Salvadora persica L., Toothbrush tree 521-530