Anti-inflammatory activity of Nectandra angustifolia (Laurel Amarillo) ethanolic extract.

Abstract

ETHNOPHARMACOLOGICAL RELEVANCE\nNectandra angustifolia belongs to the Lauraceae family and it is widely known in phytomedicine by local inhabitants of South America against various maladies. It is popularly used for the treatment of different types of inflammatory processes, like rheumatism, arthritis and its associated pain.\n\n\nAIM OF THE STUDY\nTo characterize the phytochemicals in an ethanolic extract of Nectandra angustifolia and to evaluate the total antioxidant content and its anti-inflammatory effect with multiparametric analyses through in vitro assays and an in vivo model.\n\n\nMETHODS\nLeaves and stems of Nectandra angustifolia were air-dried and an ethanolic extract (NaE) was further obtained. Total phenolic, flavonoid and tannin content were determined and the antioxidant activity was addressed by DPPH and FRAP assays. NaE was first analyzed by HPLC and then two tests were carried out as screening assays for anti-inflammatory activities: red blood cell membrane stabilization and protein denaturation. The non-cytotoxic concentration of NaE was determined for in vitro biological assays using RAW 264.7 (murine macrophages) cell cultures through cell counting with Trypan-blue and XTT assay. Subsequently, the cell cycle of RAW 264.7 cells exposed for 24 h to NaE was analyzed. Additionally, the anti-inflammatory capacity of NaE was evaluated by RT-qPCR of pro-inflammatory cytokines. Furthermore, NF-κB translocation was observed by confocal microscopy at different times. Finally, formalin-induced mice paw inflammation was used as an in vivo model.\n\n\nRESULTS\nThe chromatographic profile of NaE showed peaks compatible with flavonoids content. NaE exhibited better membrane stabilization effect on HRBC and protection of BSA denaturation than the standard drug (diclofenac). NaE diminished mRNA levels of pro-inflammatory cytokines when added 1-hour prior LPS stimulation. Moreover, NaE prevented the translocation of NF-κB to the nucleus and in formalin-induced mice paw inflammation, reduced the edema and the stimulus of inflammatory phase.\n\n\nCONCLUSION\nThis study shows for the first time, that Nectandra angustifolia ethanolic extract has a high content of flavonoids and that possess antioxidant and anti-inflammatory biological properties as demonstrated by multiparametric analyses from in vitro assays and an in vivo model of inflammation.