In-vitro analysis of free radical scavenging activities and suppression of LPS-induced ROS production in macrophage cells by Solanum sisymbriifolium extracts

The current study aims to evaluate the antioxidant, cytotoxicity activities and suppression of LPS-induced oxidative stress production and characterization of phytochemicals in Solanum sisymbriifolium leaf extracts. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2′-azino-bis3-ethylbenzothiazoline-6-sulphonic acid (ABTS) radical scavenging activity of the leaves of S. sisymbriifolium extracted with solvents of various polarities viz. water: ethanol, ratio 50: 50; ethyl acetate and dichloromethane, was assessed. The cytotoxicity of the extracts was determined using the [3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide] (MTT) assay on RAW 264.7 macrophage (Murine) cells and real-time cell analysis (RTCA) xCELLigence system was used for determining cell viability. Cell-based detection of reactive oxygen species (ROS) was investigated utilizing a 2′,7′-Dichlorodihydrofluorescein diacetate (H(2)DCF-DA) assay. The DPPH and ABTS scavenging activity results of extracts revealed a dose-dependent response with significantly lower activity in both DPPH and ABTS. The superoxide dismutase (SOD) enzyme activity was then evaluated and extracts displayed a high SOD enzyme activity with 90–50% activity. Cytotoxicity results revealed that S. sisymbriifolium extracts were not toxic to RAW 264.7 macrophage cells at the tested concentrations. All three extracts decreased the production of ROS in macrophage cells. Phytochemical analysis using Fourier-transform infrared spectroscopy (FTIR) indicated the presence of metabolite functional groups which may be responsible for the antioxidant activity. The current study indicates that S. sisymbriifolium contains phytochemicals that scavenge free radicals, with less toxicity, and suppresses the LPS-induced ROS production in RAW 264.7 macrophage cells.