夏桑叶的体外抗氧化活性及其主要功能成分研究

利用体外清除自由基评价技术,测定并比较了夏桑叶与冬桑叶对3种氧中心自由基·OH、O 2-·和1O2的清除活性。结果显示,夏桑叶对·OH和O 2-·的清除活性与冬桑叶相近,而且清除^1O2能力较冬桑叶的高61%,提示夏桑叶也是一种极具研发应用前景的纯天然医药保健资源。进一步分别用干叶热水提取法、鲜叶热水提取法和鲜叶温水提...

ANTIOXIDANT ACTIVITIES in vitro AND MAIN EFFICACY COMPONENTS IN SUMMER MULBERRY LEAVES

Scavenging activities of ·OH, O2- · and 1O2 of summer mulberry leaves and the winter mulberry leaves were determined by evaluation technology of scavengingfree radicals in vitro. The results showed that the ·OH and O2- scavenging activities of summer mulberry leaves were similar to that of winter mulberry leaves, and the capacities to 1O2scavenging activity of summer mulberry leaves were even 61% higher than that of the winter mulberry leaves. It indicated that the summer mulberry leaf is also a kind of ideal natural resources for medicine and health food. Furthermore, using 3 different extracting methods of dried leaves with hot water (Process 1), extracting from fresh leaves with hot water (Process 2) and extracting from fresh leaves with warm water (Process 3), 9 extracts were obtained from the upper, middle and lower parts of summer mulberry leaves, respectively. The antioxidant activities and main components contents (polyphenols, flavonoids, polysaccharides and proteins) of the extracts were measured, and the correlations between antioxidant activities and main components were analyzed. The results were as follows: (1) The correlation between the antioxidant capacities and polyphenols and flavonoids contents were highly significant, and the contents of polysaccharides were only significantly correlated with the capacity for scavenging1O2, while the proteins were almost no scavenging radicals capacity. It indicated that the flavonoids and polyphenols in the summer mulberry leaves played the main role of antioxidation just as in winter mulberry leaves. (2) The effects of leaf position and extraction method on the antioxidant activities and contents of main components in summer mulberry leaves needed to be considered. (3) As for extracting the bioactive substances from the summer mulberry leaves, it's better to choose the middle and upper leaves and the Process 1. In addition, if the material was fresh, it's better to choose the middle leaves and the Process 2. And the upper or lower leaves might also be utilized in some cases.