紫地丁（Osbeckia chinensis L.）之甲醇萃取物利用Amberlite XAD-2管柱層 析及二組逆相高效液相層析進行分離、純化，獲得紫地丁酸（osbeckic acid）及 punicacortein A:紫地丁酸經過各種化學反應及儀器分析結果，確認其化學結構 為2-hydroxy-2-（5-corboxy-2-furyl）acetic acid ，為首度自植物純化出來之?K喃隻羧 酸化合物。利用硫氰酸鐵法探討紫地丁酸對於α-生育醇及二種同純化自紫地丁 之沒食子酸甲基酯和 punicacortein A等酚型抗氧化劑之協力作用，得知紫地丁酸 對於上述酚型化合物之抗氧化性皆依劑量一應答之關係呈現協力作用，其強弱順 序依次為α-生育醇，punicacortein A和沒食子酸甲基酯。 Methanol extract of Osbeckia chinensis L. was chromatographed on Amberlite XAD-2 and repeatedly purified on two ststems of reversed HPLC.Osbeckic acid was obtained as a color- less oil and identified as 2-hydroxy-2- （ 5-corboxy-2-furyl ） acetic acid through the chemical reactions and instrumental analyses. Synergistic effects of osbeckic acid on the antioxidative activity of α - tocopherol and two polyphenols isolated from 0. chinensis L., methyl gallate and punicacortein A. were investigated in a food model system using the thiocyanate method. The antioxidative activity of α -tocopherol was considerably increased on concurrent use with osbeckic acid. On addition of osbeckic acid at a concentraction of 16 μ M to α -tocopherol (4 μ M), the an- tioxidative activity was found to be stronger than that of standard α -tocopherol at a concentra- tion of 16 μ M. The same synergistic effect was observed when osbeckic acid was added to- gether with methyl gallate or punicacortein A. The highest synergistic effects of osbeckic acid is α -tocopherol, following punicacortein A and methyl gallate.
