Antioxidant Function And Active Components In Fresh Rose (Rosa Rugosa) Flowers

There are good resources of fresh flowers, and many of them are widely used as traditional medicines and food products in China. The components with antioxidant activities or specified health use are rich in flowers and can act as dietary supplement. It becomes a hot field to exploit and utilize natural antioxidant resource.The antioxidant effects in 45 kinds of fresh flowers obtained in this study were evaluated in three ways: using l,l-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, hydroxyl radical scavenging activity and superoxidant-dismutase (SOD)-like activity. The results were showed there was significant correlation-ship (p<0.01) between DPPH radical scavenging activities and polyphenolics. This indicated that polyphenolics should act as active components in flowers. Carmine rose was a good scavenger to the three kinds of free radicals and the scavenging activities of 1.00mg fresh rose flowers on DPPH' was equal to 18.74 μ g Vc.Several effect factors were tested as follows: (1) There was significant correlation-ship (p<0.01) between three radical scavenging activities of a variety of rose buts and flowers; (2) The contents of polyphenolics and flavonoids in different developmental stage were decreased, as well as the scavenging activities to the three radicals. But the mean weight of each fresh flower was highest in developmental stage 6; (3) The scavenging activities to the three radical scavenging activities increased following the increasing contents of polyphenolics, flavonoids and Vc at the beginning of short-term storage. Low-temperature treatment was an effective measure for preserving antioxidants; (4) The results proved that boiling water was the best solvent for extracting main components of rose, compared with different solvents such as acetone, water and ethyl acetate on the effect of ultrasound; (5) The scavenging activities of aqueous extracts increased when increasing its extracting temperature. Both scavenging activities and the contents of polyphenolics had no significant difference (P>0.05) after extracting for 30 min at 100 ℃; (6) The effects of various concentration of extracts on the DPPH'were examined, and the relationship betweenconcentration and scavenging activities had a linear dose-response relationship (r=0.991; y =15.792x + 14.745); (7) pH 5 was considered to be the best extracting pH values, which had a significant difference at 5% level with others and the scavenging activities were limited in alkaline conditions.18 compounds had been identified by gas chromatography/mass spectrometry, among which 75.014 percentages had hydroxyl group. The aqueous extracts were fractionated on sephadex G-100, polyamide, sephadex LH-20 and CM-52 columns using water/ethanol as the solvent. The results showed fractions separated from CM-52 column possessed a remarkable antioxidant activity compounds, which still existed high scavenging activities after 120 days in 4℃ storage.