Globally, striving to find eco-friendly pest control agents increased day after day toward plant metabolites.  Through current work, three flavonoids were isolated from Cynara cardunculus and identified as Apigenin, Luteolin, and Luteolin-7-O-glucoside using UV, IR, and MS spectrometry analyses. The three compounds were evaluated for their anti-feeding and deterrence activity against 4th instar larvae of cotton leafworm Spodoptera littoralis using both dual and no-choice leaf disk tests.  results revealed that Luteolin-7-O-glucoside recorded the strongest insect antifeedant activities reached (74.50, 91.40%) followed by Apigenin (53.45% & 71.61%) in both choice tests respectively, while the antifeedant index of Luteolin did not exceed 22% in the concentration of 1000 ppm. Moreover, the activity of digestive enzymes; amylase, and invertase decreased significantly according to the deterrence activity level of the tested compound while protease activity showed non-significant changes in treated larvae. Noteworthy, the structure -feed deterrence activity relationships of flavonoids was observed and considered. Thus flavonoids can protect crop plants from insect infestation according their chemical structure.