The present study has reported the isolation, characterization, antioxidant and antiulcer activity of a new triterpenoid extracted from Cucurbita pepo seeds. The seed extract was subjected to column chromatography for the isolation of constituents. The isolated compound was characterized by Infra red, 1Hydrogen Nuclear Magnetic Resonance, 13Carbon Nuclear Magnetic Resonance which allow the identification of isotopic hydrogen and carbon atoms in a molecule, respectively. The isolated compound was a tetracyclic triterpenoid which possesses basic cucurbitacin skeleton characterized as 19-(10→9β)-abeo-10α-lanost-5-ene. The isolated compound showed maximum antioxidant activity i.e. 72.8±0.15% by 1, 1 diphenyl -2- picryl hydrazyl method at 300 μg mL-1 as compared to ascorbic acid. Further, it was evaluated for anti ulcerogenic activity, extracted triterpenoid showed optimum percentage inhibition i.e., 55.7, 67.1 and 59.1% by Pyloric Ligation, Water Immersion Stress and NSAID (Indomethacin) induced ulcer method at 300 μg mL-1 dose in rats. It can be inferred from the above study that the extracted tetracyclic triterpenoid have potent anti-ulcer activity due to its antioxidant potential and can be used as natural antiulcerogenic agent.