The growth inhibitory activity of the leaf extract of plants (Viola odorata, Gardenia gummiferra, and Anthocephalus cadamba) belonging to family Rubiaceae and Violaceae was studied against H. armigera, an economically important pest of cotton and legumes in India. The EC20 and EC50 values were found to be in the range of 100 to 600 ppm and 400 to 600 ppm, respectively. The extracts at EC50 with natural diet did not affect the relative consumption rate(RCR), approximate digestibility (AD) and efficiency of conversion of ingested food (ECI) but the relative growth rate (RGR) and efficiency of conversion of digested food (ECD) were found to be affected, indicating chronic toxicity rather than antifeedent activity. The retardation in growth in larvae was marked and visible with Viola odorata. Biochemically, the lipase, superoxide dismutase (SOD) and catalase activities, as well as lipid peroxidation, were found to be affected as a function of treatment with the extracts. HPLC chromatograms of the partially purified extract yielded sharp and symmetrical peaks at 17.5, 11.5 and 7.4 min for V. odorata, G. gumiferra and A. cadamba, respectively, indicating the presence of circular proteins in the plant extracts.