From the Et acetate fraction of the alc. ext. of the flowers of Sinapis arvensis L. a new compd. given the name: (2,​2'-​diacetyloxy-​3,​3'-​dihydroxy)​-​1,​1'-​dipropylether.  In addn., three flavonoidal glycosides were also isolated and identified as: kaempferol-​3-​O-​β-​glucopyranoside, isorhamnetin-​3,​7-​O-​β-​diglucopyranoside and isorhamnetin-​3-​O-​β-​glucopyranoside-​7-​O-​α-​rhamnopyranoside.  Meanwhile the chloroform fraction of the alc. ext. of the seeds afforded β-​amyrin, β-​sitosterol, β-​sitosterol-​3-​O-​β-​glucopyranoside and syringin.  The GC​/MS anal. of the fixed oil of the seeds revealed the presence of 14 fatty acids including a high percent (11.56​%) of harmful erucic acid.  The identification of the isolated compds. was based on different methods of phys., chem. and spectral anal.  Moreover the biol. screening showed that the alc. ext. of the leaf, the flavonoids of the flower and to a lesser extent the oil of the seed possesses a significant antimicrobial activity, while the flavonoids of the flower showed a significant anti-​inflammatory activity.  In addn., the oil of the seed showed insignificant diuretic activity.