ANTIOXIDANT ACTIVITY AND ACUTE TOXICITY OF EXTRACT OF UVARIA GRANDIFLORA ROXB. EX HORNEM - ANNONACEAE 
Background: Uvaria grandiflora, a naturally occurring medicinal plant in Central Vietnam, showed many significant biological activities. The objective of the study was to evaluate the antioxidant activity through the ability of Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging and the acute toxicity of extract of U. grandiflora. Materials: The aerial part of U. grandiflora. Method: Evaluation the ability of DPPH radical scavenging by the method of Kedare (2011). Evaluation of acute toxicity by the method of Abraham and Turner (1978). Results: The crude methanol extract and ethyl acetat fraction displayed the IC50 values 88.49 µg/ml and 65.57 µg/ml, respectively. On acute toxicity, the LD50 value could not be identified at the maximum dose given to mice (10000 mg/kg mice). Conclusion: Extract of methanol and ethyl acetat fraction of Uvaria grandiflora showed moderate antioxidant activities. The LD50 value could not be identified. Key words: antioxidant, acute toxictity, DPPH, free radical, Uvaria grandiflora