Impact of rapeseed pomace extract on markers of oxidative stress and DNA damage in human SH-SY5Y cells.

With increased longevity and subsequent rise in people with age-related neurodegenerative diseases, protection of neurons from oxidative stress damage has become an important field of study. For the first time, we highlight the neuroprotective properties of rapeseed pomace (RSP) extract in SH-SY5Y human neuroblastoma cells. We used resazurin to determine cell metabolism, 2,7'-dichlorofluorescin diacetate (H2 DCFDA) to assess the potential of RSP extracts to shield cells from reactive oxygen species (ROS) induced by H2 O2 using flow cytometry, HPLC to analyze for malondialdehyde (MDA) as a lipid peroxidation marker and the COMET assay to assess DNA strand breakage. Protein stress arrays were used to investigate the cellular pathways affected by RSP extract. No effect on cell metabolism in SH-SY5Y cells was observed after RSP extract treatment (up to 1.5 mg/ml). Pretreatment (24 hr) with RSP extract (1 mg/ml), before H2 O2 -induced stress, alleviated ROS production and DNA strand breakage by 68%, and 38%, respectively. At protein level, the RSP extract increased the levels of FABP-1, HIF-1α, SOD2, and Cytochrome c proteins. Under H2 O2 -induced stress, however, it helped to downregulate p38α levels, a protein kinase which is receptive to stress impulse (mitogen-activated). RSP extract shows very promising cell protective properties in relation to oxidative stress. PRACTICAL APPLICATIONS: Oxidative stress has been associated with numerous diseases for example cancer, diabetes, and many neurological disorders including Parkinson's and Alzheimer's diseases. Hence, there is acceptance among the scientific community of antioxidant therapy and the quest for effective, low cost and readily available sources of natural antioxidants is paramount. Rapeseed plantations are abundant around the world due to the use of rapeseed oil in cooking and as a biofuel. The resulting rapeseed pomace (by-product), specifically its extract, contains high levels of phytochemicals that protect cells against oxidative stress. Therefore, RSP extract can potentially be used/developed as functional food and nutraceuticals in the prevention of many complex neurodegenerative diseases.

A clickable probe for versatile characterization of S-nitrosothiols.

S-nitrosation of cysteine thiols (SNOs), commonly referred to as S-nitrosylation, is a cysteine oxoform that plays an important role in cellular signaling and impacts protein function and stability. Direct labeling of SNOs in cells with the flexibility to perform a wide range of cellular and biochemical assays remains a bottleneck as all SNO-targeted probes to date employ a single analytical modality such as biotin or a specific fluorophore. We therefore developed a clickable, alkyne-containing SNO probe 'PBZyn' based on the o-phosphino-benzoyl group warhead that enables multi-modal analysis via click conjugation. We demonstrate the utility of PBZyn to assay SNOs using in situ cellular imaging, protein blotting and affinity purification, as well as mass spectrometry. The flexible PBZyn probe will greatly facilitate investigation into the regulation of SNOs.

Determination of sinapine in rapeseed pomace extract: Its antioxidant and acetylcholinesterase inhibition properties.

Sinapine is the main secondary metabolite present in rapeseed pomace (RSP) with its concentration being dependent on rapeseed processing, growing conditions, extraction parameters and the country of origin. Here we report, the concentration of sinapine from an extract of defatted RSP harvested in the North East of Scotland. Using liquid chromatography tandem mass spectrometry, the most abundant phenolic compound in the RSP extract was, as expected, sinapine (109.1 mg/g RSP extract). Additionally, sinapic, caffeic, ferulic and syringic acids were identified (0.159-3.91 mg/g RSP extract). Sinapine together with the phenolics at the concentration present in the RSP extract, exhibited ≥50% activity relative to the extract in antioxidant assays. Furthermore, sinapine provided plasmid DNA (pBR322) protection, from 2,2'-azobis(2-amidinopropane) dihydrochloride and inhibited acetylcholinesterase activity by 85%. Molecular docking was utilised to explain the inhibitory activity. RSP can be an excellent source of bioactive compounds for pharmaceuticals, food additive and nutraceutical applications.