Antioxidants from a Chinese medicinal herb -: Lithospermum erythrorhizon
Antioxidants from a Chinese medicinal herb -: Lithospermum erythrorhizon
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DOI：
10.1016/j.foodchem.2007.01.031
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发表时间：
2008-01-01
期刊：
影响因子：
8.8
通讯作者：
Bi, Kaishun
中科院分区：
文献类型：
--
作者：
Han, He;Weng, Xinchu;Bi, Kaishun
从紫草（Lithospermum erythrorhizon Sieb et.）中分得7个化合物，分别为脱氧紫草素（1），β，β-二甲基丙烯酰紫草素（2），异丁基紫草素（3），紫草素（4），5，8-二羟基-2-（1-甲氧基-4-甲基-3-戊烯基）-1，4-萘二酮（5），β-谷甾醇（6）和两种咖啡酸酯的混合物[7（7a，7 b）]。Zucc.并通过光谱方法鉴定。其中化合物5为首次从该植物中分离得到。通过Rancimat法、还原力和自由基清除能力对7个化合物的抗氧化活性进行了比较和评价。结果表明，除化合物6外，其余6个化合物对4种不同的方法均表现出明显的抗氧化活性。化合物4和化合物7对猪油氧化的抑制作用比BHT强得多，且均具有较强的还原能力。用Rancimat法和还原力法测定其抗氧化活性，其顺序分别为化合物7 > 4 > BHT > 2 > 3 > 5 > 1 > 6和化合物7 > BHT > 4 > 2 similar to 3 similar to 5 > 1 > 6。此外，化合物1-5对ABTS（中心点+）均表现出很好的自由基清除活性，但对DPPH中心点表现出中等程度的抑制作用，而化合物7对ABTS（中心点+）和DPPH中心点均表现出较强的自由基清除活性。因此，我们的研究结果表明，L。刺桐根可能是一种有前途的丰富的天然抗氧化剂来源。(c)2007爱思唯尔有限公司版权所有。
Seven compounds, deoxyshikonin (1), beta,beta-dimethylacrylshikonin (2), isobutylshikonin (3), shikonin (4), 5,8-dihydroxy-2-(l-methoxy4-methyl-3-pentenyl)-l.4-naphthalenedione (5), beta-sitosterol (6) and a mixture of two caffeic acid esters [7 (7a,7b)] were isolated from Lithospermum erythrorhizon Sieb et. Zucc. and identified by spectroscopic methods. Among them, compound 5 was isolated from this plant species for the first time. The antioxidant activities of the seven compounds were compared and evaluated through Rancimat method, reducing power and radical scavenging activity. Results showed that, except compound 6, another 6 compounds all exhibited obvious antioxidant activities against four different methods. Compounds 4 and 7 exerted much more potent antioxidant effects on retarding the lard oxidation than that of BHT and both were found to exhibit strong reducing power. Their antioxidant activities, assessed by Rancimat method and reducing power, decreased in the following order, respectively: compound 7 > 4 > BHT > 2 > 3 > 5 > 1 > 6 and compound 7 > BHT > 4 > 2 similar to 3 similar to 5 > 1 > 6. In addition, compounds 1-5 all exerted very good radical scavenging activities toward ABTS(center dot+) but showed moderate inhibition of DPPH center dot, while compound 7 presented as a powerful radical scavenger against both ABTS(center dot+) and DPPH center dot. Thus, our results suggested that L. erythrorhizon could be a promising rich source of natural antioxidants. (c) 2007 Elsevier Ltd. All rights reserved.