Screening And Bioactive Studies Of The Natural Active Substances In Cotoneaster Multiflorus Bunge

Some bioactivities of the different crude extracts from Cotoneaster multiflorus Bunge fruit were studied in the present work.This species was belongs to plants of genus Cotoneaster Medikus in the family Rosaceae.The aim of this work was to find the natural products of antioxidant and antitumor in order to provide the experimental bases to protect and exploit this widespread resources.The antioxidant activities of all the different crude extracts of C.multiflorus Bunge fruit were assayed by DPPH^?,ABTS^?inhibition assays and pyrogallol autooxidation assay.The results showed that the different crude extracts from C. multiflorus Bunge fruit had strong antioxidant activities.Among them,EtOAC extracts had the strongest antioxidant activity against DPPH.Its EC₅₀was 7.5μg/ml; EC₅₀of water extracts was 118.45μg/ml;EC₅₀of Petroleum Ether extracts was 174.34μg/ml.At the concentration of 50μg/ml,the scavenging activity of EtOAC extracts was 91.86%which was obviously higher than the activity of positive control BHA,78.26%.EtOAC extracts had the strongest antioxidant activity against ABTS⁺ free radical and its EC₅₀was 4.6μg/ml;EC₅₀of water extracts was 23.7μg/ml;EC₅₀of Petroleum Ether extracts was 26.1μg/ml.The antitumor activities of the different crude extracts of C.multiflorus Bunge were measured by MTT in vitro.IC₅₀of EtOAC extracts was 314.5μg/ml which appeared the highest cytotoxic effects on human liver cancer cell line 7721.The IC₅₀of Petroleum ether and water extracts was about 387.3μg/ml and 512.7μg/ml,respectively.The highest contents of total phenolics and total flavonoids were observed in the EtOAC extract and they were accordance with its antioxidant properties.After further purification of EtOAC extracts of C.multiflorus Bunge fruit by column chromatography,nine fractions were collected.Among them,the Fraction 3 showed the higher antioxidant activities and antitumor activities,and it contained extremely high contents of total phenolics and total flavonoids.The high correlation between antioxidant properties and contents of total phenolics and flavonoids suggested that the contents of total phenolics and flavonoids were responsible for antioxidant activities of C.multiflorus Bunge.After HPLC analysis to Fraction 3 and Fraction 5,the main peaks of two fractions were noted at 6.153min and 5.264min,respectively.