Nitric oxide (NO) is a key mediator that plays an important role in pathogenesis of various chronic diseases like Alzheimer's disease and Parkinson's disease. Additionally, there is a great attitude for finding natural compounds, which could control and inhibit NO production in pathological conditions. Therefore, we were encouraged to investigate the effects of some Lamiaceae species on NO production and cell injury during oxidative stress in PC12 cells. In this study, cell death determined by MTT assay and NO levels were evaluated using Griess assay. PC12 cells were exposed to total metanolic extracts of three Scutellaria and one Nepeta species. The results revealed that Nepeta laxiflora (N. laxiflora) could protect PC12 cells from hydrogen proxide-induced oxidative stress and all of the plants inhibited NO production in that condition except Scutellaria tournefortii (Sc. tournefortii). In addition, Scutellaria multicaulis (Sc. multicaulis) was meanwhile subjected to fractionation using different organic solvents. The dichloromethan and ethyl acetate fractions of Sc. multicaulis could protect PC12 cells from oxidative stress injury. However, NO production was restrained by the hexane and dichloromethane fractions. Considering the results, N. laxiflora, Scutellaria nepetifolia (Sc. nepetifolia), and Sc. multicaulis are good candidates for further investigations in neuroprotection and anti-inflammation studies.
Keywords: Griess assay; Nepeta; Nitric oxide; Oxidative stress; PC12 cells; Scutellaria.