LAUSR

Abstract Due to the excellent ethnopharmacological properties of Phlomis crinita, it is widely used as natural remedy in the Mediterranean region. This study inspects the effect of micro and nano sized particles, contained in aqueous and hydromethanolic leaves extracts, on the antioxidant activities, phenolic and flavonoid contents. The macro particles were removed from extracts via filtration whereas the micro and nano particles were isolated through speed centrifugation. Antioxidant activities were screened in vitro by β-carotene-linoleic acid and 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radical scavenging assays. The results showed that removal of microparticles don’t affect the properties of extracts, whereas the nanoparticles contributed much in the content of total phenolics and antioxidant potencies of both extracts. The highest impact of nanoparticles removal on antioxidant activity was observed in methanolic extract losing 72% of β-carotene bleaching inhibition and four-doubled its IC50 index. These findings suggest that nano sized particles are the nature’s store of bioactive constituents in herbal extracts, therefore their retention is highly recommended to preserve the totality of antioxidant capacities.