Antioxidant and anti-inflammatory properties of an ethanolic extract of Nectandra angustifolia "Yellow Laurel”

Abstract

Nectandra angustifolia (N.a.) is a native plant whose leaf and bark extracts have been used in ethnomedicine for the treatment of rheumatism, arthritis, chronic pain and as an antivenom in snakebites. Therefore, the objective of this work was to characterize its possible biological activities. Leaves and stems of N.a. were air-dried and an extract (NaE) was further obtained by maceration with ethanolic. Total flavonoid content and antioxidant activity were determined on NaE using the aluminum trichloride technique and DPPH respectively. The chromatographic profile of NaE was subsequently determined by HPLC identifying peaks compatible with flavonoids. The non-cytotoxic concentration of NaE (50 µg/mL) was determined for in vitro biological assays using Raw 264.7 (murine macrophages) cell cultures through cell counting with Trypan-blue and XTT Kit® assay. Subsequently, the cell cycle of RAW 264.7 cells exposed to NaE (10, 50 and 100 µg/ml) was analyzed for 24 h, revealing a dose-depending decrease in S-phase cells, as well as, an enhancement of the sub-Go population compared to control cells. These data are compatible with a NaE induction of cell apoptosis. Additionally, the antiinflammatory capacity of NaE was evaluated by RT-qPCR. Briefly, proinflammatory cytokine gene expression (IL-1 and IL-6) were determined in cells preincubated with NaE and, subsequently stimulated with LPS compared to those treated with LPS alone. Experimental data show that NaE decreases the release of proinflammatory cytokines at different exposure times (4 and 24 h). These preliminary results show that NaE contains natural components with antioxidant and anti-inflammatory properties that would be an attractive option for the future design of phytotherapeutics with different applications in biomedicine.