AIM: To determine whether morroniside, a compound in Cornus officinalis Sieb et Zucc can prevent cultured human umbilical vein endothelial cells (HUVEC) from damage by high ambient glucose. METHODS: HUVEC was incubated in glucose, 5 or 30 mmol/L, either alone or in the presence of morroniside (final concentration 100, 10, and 1 μmol/L, respectively) for 48 h. The proliferation of HUVEC was quantified by MTT method; its cycle was analyzed by flow cytometry; morphological change was observed with fluorescence microscopy. RESULTS: Survival of HUVEC cultured in high ambient glucose was significantly decreased when compared to that in normal concentration of glucose (P<0.01). High ambient glucose also lowered the rate of cells entering into S-phase, along with severe morphological damage. With the intervention of morroniside (final concentration 100 and 10 μmol/L), the cell survival was significantly recovered (P<0.01, P<0.05, respectively), accompanied with increased S-phase rate and less extent of morphological damage. CONCLUSION: Morroniside protected HUVEC against high ambi- ent glucose induced injury, which suggested that morroniside could exert a beneficial effect on preventing diabetic angiopathies. AIM: To determine whether or not morroniside, a compound in Cornus officinalis Sieb et Zucc can prevent human umbilical vein endothelial cells (HUVEC) from damage by high ambient glucose. METHODS: HUVEC was incubated in glucose, 5 or 30 mmol / L, either alone or in the presence of morroniside (final concentration 100, 10, and 1 μmol / L, respectively) for 48 h. The proliferation of HUVEC was quantified by MTT method; its cycle was analyzed by flow cytometry; morphological change was observed with fluorescence microscopy . Survival of HUVEC cultured in high ambient glucose was significantly decreased when compared to that in normal concentration of glucose (P <0.01). High ambient glucose also lowered the rate of cells entering into S-phase, along with severe morphological damage. With the intervention of morroniside (final concentration 100 and 10 μmol / L), the cell survival was significantly recovered (P <0.01, P <0.05, respectively), accompanied with increased S-phase rat CONCLUSION: Morroniside protected HUVEC against high ambi- ent glucose induced injury, which suggested that morroniside could exert a beneficial effect on preventing diabetic angiopathies.