Systematic evaluation of radical scavenging active compounds in some edible plants using some different methods

本研究采用不同的方法评价了几种食用植物成分的体外自由基清除活性，并阐明了这些抗氧化剂的化学结构和活性关系根据NMR和MS等波谱技术，从而测定出六种二甲基丁烷木脂素和四种四氢呋喃木脂素。采用DPPH自由基和O2-自由基清除能力评价和ORAC（OxygenRadicalAbsorbanceCapacity）评价3种方法测定了木脂素的自由基清除能力。DPPH自由基清除和ORAC方法测定的活性似乎取决于苯环上羟基的数量。然而，具有苄基亚甲基的木脂素倾向于显示出比具有氧的木脂素更高的对DPPH自由基的清除能力 关于我们 取代的苄基碳，而倾向于显示较低的ORAC。其次，从多花蒲桃（Syzygium polyanthum）叶中分离得到5个亲水性化合物，分别鉴定为2个杨梅苷和3个鞣花单宁。用上述三种方法测定了这五种化合物以及从乙酸乙酯萃取物中分离得到的鞣质和黄酮类化合物的自由基清除活性。清除DPPH自由基的活性与苯环上羟基的数目有关。相反，比较具有相同邻位三羟基苯基（o-THP）数目的5种鞣花单宁的O 2-自由基清除活性表明，分子中六羟基联苯酰基（HHDP）数目越多，活性越大。另一方面，分子中含有3个以上o-THP基团的单宁的ORAC不受没食子酰基和HHDP基团数量的影响，因此，3种不同方法得到的自由基清除能力不一定相同，因此，评价抗氧化剂需要多种方法。少

This study was aimed to evaluate in vitro radical scavenging activity of some edible plant constituents using some different methods and elucidate chemical structure and activity relationship of these antioxidants.Firstly, ten lipophilic compounds were isolated from Papuan nutmeg and mace (Myristica argentea) and their structures were elucidated on the basis of spectroscopic evidences of NMR and MS, resulting in determination of six dimethylbutane lignans and four tetrahydrofuran lignans. Radical scavenging activities of these isolated lignans were measured by three different methods, evaluation of scavenging effects on DPPH radical and O2- radical, and evaluation of ORAC (Oxygen Radical Absorbance Capacity). The activities measured by both DPPH radical scavenging and ORAC methods seemed to be dependent on the number of hydroxyl groups on the benzene ring. However, lignans having benzyl methylene tended to show a higher scavenging ability against DPPH radical than lignans having oxygen … More ated benzylic carbon, while tended to show a lower ORAC. On the other hand, no clear relationship was observed between the chemical structure of lignans and their scavenging activity against O2- radical.Secondarily, five hydrophilic compounds were isolated from salam leaves (Syzygium polyanthum) and they were identified as two myricetin glycosides and three ellagitannins. The radical scavenging activities of these five compounds together with some tannins and flavonoids which had been previously isolated from the ethyl acetate soluble fraction were measured using three different method mentioned above. The DPPH radical scavenging activity was dependent on the number of hydroxyl groups on the benzene ring. On the contrary, comparing the O2- radical scavenging activity in five ellagitannins having the same number of ortho-trihydroxyphenyl (o-THP) groups indicated that the more the number of hexahydroxydiphenoyl (HHDP) groups were in the molecule, the more the activity was. On the other hand, ORAC of tannins having more than three o-THP groups in the molecule was not influenced by the number of galloyl and HHDP groups.Consequently, the radical scavenging abilities obtained by three different methods were not necessarily the same, therefore, more than one method are required to evaluate antioxidants. Less