Antioxidant Activities and Main Active Compounds of Solvent Extracts from Rubus pungens var. oldhamii

This study investigated effects of using water and different organic solvents (such as 60% ethanol, chloroform, ethyl acetate, butanol and methanol) on the total polyphenols, flavonoids, and antioxidant capacity of R. pungens var. oldhamii. The 60% ethanol and butanol extracts possesses a high amount of total phenolic and flavonoid contents, respectively. Antioxidant potential of extracts was assessed by 1,1-Diphenyl-2-picrylhydrazyl (DPPH.), superoxide anion radical (O-2(.-)), hydroxyl radical (HO.) scavenging assays. The butanol extract showed the highest inhibition of DPPH. and HO. assays; moreover, the water extract had the best activity in scavenging of superoxide radical. The 60% ethanol extract showed high DPPH. scavenging activity. Concerning environment and human health, the 60% ethanol extract was considered for further study. Phytochemical investigation of the EtOAc fraction of the 60% ethanol extract led to isolation of two known compounds (salicylic acid and dibutyl phthalate). Antioxidant activity of the salicylic acid (SA) was determined by a superoxide radical scavenging assay. It was observed that SA exhibited good antioxidant activity. These results suggest that the 60% ethanol and butanol extracts have good antioxidant activities which were correlated with its high level of phenolics and flavonoids, and the SA may play a promising role in protection from oxidative stress.