Department of Pharmacological and Biomolecular Sciences, Università degli Studi di Milano, Milan, Italy.
Plant Foods Hum Nutr. 2013 Jun;68(2):149-54. doi: 10.1007/s11130-013-0354-0.
This study investigates whether infusions of green and black tea inhibit the NF-κB driven transcription in human epithelial gastric AGS cells. Water extracts were prepared from different brands of green and black tea available on the Italian market. Teas with or without caffeine were studied. An industrially prepared freeze-dried water extract of green tea was also tested. Catechin and caffeine contents were measured by HPLC analysis. The decrease in phenol and catechin content three months after the expiry date was also investigated. The NF-κB driven transcription and the free radical scavenger activity were inhibited, and this effect was related to catechin levels. The potency of epigallocatechin 3-gallate in inhibiting NF-κB driven transcription is so great that tea extracts low in epigallocatechin 3-gallate are still highly active. In one decaffeinated sample of green tea, the phenol and catechin content was very low, probably as a consequence of caffeine removal. The decrease in catechin levels after 3 months did not reduce the inhibition of NF-κB driven transcription by tea infusions. This is the first paper reporting the inhibitory effect of NF-κB of commercial green and black infusions at the gastric level, evaluating their stability as well.
本研究旨在探讨绿茶和红茶的提取物是否能抑制人胃上皮 AGS 细胞中 NF-κB 驱动的转录。从意大利市场上可获得的不同品牌的绿茶和红茶中制备水提取物。研究了含或不含咖啡因的茶。还测试了一种工业制备的绿茶冻干水提取物。通过 HPLC 分析测定儿茶素和咖啡因的含量。还研究了过期后三个月内酚类和儿茶素含量的下降情况。NF-κB 驱动的转录和自由基清除活性受到抑制，这种作用与儿茶素水平有关。表没食子儿茶素没食子酸酯抑制 NF-κB 驱动转录的效力如此之强，以至于儿茶素含量低的茶提取物仍具有高度活性。在一种去咖啡因的绿茶样品中，儿茶素和表没食子儿茶素没食子酸酯的含量非常低，可能是由于咖啡因的去除。儿茶素水平在 3 个月后下降并没有降低茶提取物对 NF-κB 驱动转录的抑制作用。这是第一篇报道商业绿茶和红茶提取物在胃水平上抑制 NF-κB 的论文，并评估了它们的稳定性。
