Abstract

There has been an increasing interest in natural products with the ability to inhibit telomerase activity in tumour and cancerous cells. Green tea catechins have been reported previously to inhibit telomerase, but it was unknown whether catechins from other plant sources could exhibit this property. We isolated 2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H-chromene-3,5,7-triol (catechin without the presence of a galloyl unit) from the stem bark of B. africana, and tested its ability to inhibit recombinant, partially purified telomerase produced in rabbit reticulocyte lysates. The B. africana catechin inhibited the telomere extension activity of telomerase with an IC₅₀ of approximately 4.7 µg/ml. This finding indicates that the galloyl unit may not be solely responsible for the inhibition of telomerase activity by catechins. This is the first report of the telomerase-inhibiting potential of catechin from the stem bark of B. africana.

摘要

人们越来越关注能够抑制肿瘤和癌细胞中端粒酶活性的天然产物。此前有报道称绿茶儿茶素可抑制端粒酶，但尚不清楚来自其他植物来源的儿茶素是否会表现出这种特性。我们从 B.africana 的茎皮中分离出 2-(3,4-dihydroxyphenyl)-3,4-dihydro-2H- chromene -3,5,7-triol（不含没食子酰单元的儿茶素），并进行了测试它能够抑制兔网织红细胞裂解物中产生的重组的、部分纯化的端粒酶。B.africana儿茶素抑制端粒酶的端粒延伸活性，IC ₅₀约为 4.7 µg/ml。这一发现表明，没食子酰单元可能不是儿茶素抑制端粒酶活性的唯一原因。这是第一份关于来自B. Africana茎皮的儿茶素抑制端粒酶潜力的报道。