Screening Of Antioxidant Activity Of Flowers And Study On The Antioxidant Activity Of Rose (Rosa Hybrid Hort. Var. Cardinal)

Anti-aging biology and free radical biology were two hot topics of modern life science in the recent years. The research and development of new antioxidant functional food and the natural antioxidants can meet the increasing demands of human for health and longevity. The flowers have been used as foods and medicines for a long time in our country. The exploitation potential of flowers in the field of functional food and the natural antioxidants is undoubtedly of broad future.In this research, the antioxidant activity (AOA) of flowers were compared and screened. After acquiring flower material of high AOA, the factors that affected the AOA were studied, and furthermore, the nutrients and biologically active components were analyzed. The main results were as follows:1. Through analyzing 46 kinds of flowers, we found that Rosa L. (Rosaceae), Lagerstroemia indica L., Euphorbia antiquorum L., Rhododendron L. Osmanthus fragrans Lour, had strong AOA and abundant polyphenols; The relationship between AOA and polyphenols contents of flowers are significant at 1% level.2. The AOA of rose flowers was confirmed through five methods. After that the AOA in different parts of rose flower organs and petals from various developmental stages and have been investigated. It was found that the AOA of petals, stamen & pistil was higher than other parts; The AOA of petals trended to be lower during the process of development, mature and ageing.3. In order to study the influence factors of AOA of rose flowers, the effects of drying and extraction methods on the AOA of rose flowers were investigated. The results indicated that drying after high-temperature short-time pretreatment was rather effective to maintain their AOA; the AOA of water extracts was stronger when the temperature was raised from 25℃ to 100℃;By using orthogonal test, the optimum extraction conditions of rose flowers were: solvent-75% ethanol; ratio of material and solven-1: 10; extraction times-three times with 24 h at one time, at the room temperature. The extracts obtained by 75% ethanolwere fractionatedly extracted with petroleum, diethyl ether, ethyl acetate and n-Butanol in turn, and the various fractions' AOA were analyzed. The results showed that the ethyl acetate fraction had the strongest AOA. The main antioxidant components in rose flowers are probably some poplar polyphenolic compounds, including tannins, flavones glycoside and procyanidins, ect.4. The contents of nutrients and some biologically active compositions in rose flowers (Rosa hybrid Hort. var. Cardinal) were determined. Rose flowers had high contents of protein, Vc, dietary fibre, polyphenols and flavonols, high proportion of essential amino acid in total amino acid and high proportion of linoleic acid in total unsatured fatty acid. The great application value of rose flowers in the field of functional food was discussed.