Characterisation of compounds from Brassica oleracea (Kale) using LC-MS/MS and evaluation of their hepatoprotective activity

1-O-Feruloylglucose (1), Iaa-glucose (2), coniferyl alcohol (3), withanolide A (4) and sulfoquinovosyl diacylglycerols (SQD) were identified in Brassica oleracea (Kale) using liquid chromatography-quadrupole time-of-flight tandem mass spectrometry. An in-silico investigation revealed CASP3, MAPK14, TNF, NOS2, BCL2, and ALOX5 to be targets for interaction. CASP3 (degree: 6) and MAPK14 (p38; degree: 6) were recognised as core targets regarding the potential role of kale compounds in liver protection. The hepatoprotective effects of 1 and 4 were validated in HepG2 cells, demonstrating increased viabilities of up to 73.0% (1 μM) and 77.1% (0.5 μM), respectively. Mechanistically, 1 and 4 treatments reduced p-p38 expression, as revealed by a significant decrease in p-p38/p38 ratios. Moreover, the treatments inhibited CASP3 activation from occurring in response to hepatocyte injury. Our findings provide a comprehensive summary of the active compounds in B. oleracea (Kale), which will be of value to further studies of functional foods.