Laboratory of Microbial Ecology and Technology (LabMET), Ghent University, Coupure Links 653, B-9000 Gent, Belgium.
Environ Microbiol Rep. 2009 Apr;1(2):100-9. doi: 10.1111/j.1758-2229.2009.00011.x. Epub 2009 Feb 2.
For many centuries, hops (Humulus lupulus L.) have been used as essential ingredient in beers, providing the typical bitterness and hoppy flavour. However, the last few years the plant has gained increasing attention as a source of prenylflavonoids and in 1999, 8-prenylnaringenin (8-PN) was identified as the most potent phyto-oestrogen known so far. Hop extracts are therefore now marketed to reduce menopausal complaints. However, 8-PN concentrations in hops are very low, and variable efficiency of these extracts was observed. Yet, hops also contain isoxanthohumol (IX) in much higher amounts (IX/8-PN ratio in hop extracts is typically 10-20). This article reviews our recent findings on how the human intestinal microbiota may activate IX. Depending on inter-individual differences in the intestinal transformation potential, this conversion could easily increase the 8-PN exposure 10-fold. The variability in efficacy of hop extracts may therefore be explained by variable intestinal metabolism. Based on this scientific knowledge, an innovative strategy was developed to decrease this variability. First, Eubacterium limosum, capable of rapidly metabolizing all IX into 8-PN, was isolated from the complex intestinal ecosystem. This bacterium was then used to develop a new generation of hop products with increased reliability in effect. This strategy involves the use of the bacterium as probiotic, in which the bacterium is administered in combination with the original hop extract. This leads to efficient intestinal 8-PN production, also in individuals who originally did not harbour the appropriate bacteria. The findings presented in this review can therefore be considered as a typical example that good insight in the specific metabolic potential of complex microbial communities and individual bacterial species may offer important opportunities for the management and modulation of the microbial organization towards a certain metabolic function.
数个世纪以来，啤酒花（Humulus lupulus L.）一直被用作啤酒的重要原料，赋予啤酒独特的苦味和啤酒花风味。然而，近年来，这种植物作为类异戊二烯黄酮类化合物的来源引起了越来越多的关注，1999 年，8- prenylnaringenin（8-PN）被鉴定为迄今为止已知的最有效的植物雌激素。因此，啤酒花提取物现在被推向市场以减轻更年期症状。然而，啤酒花中的 8-PN 浓度非常低，并且这些提取物的效率存在差异。然而，啤酒花中也含有较高含量的异黄腐醇（IX）（啤酒花提取物中的 IX/8-PN 比值通常为 10-20）。本文综述了我们最近关于人类肠道微生物群如何激活 IX 的发现。由于个体间肠道转化潜力的差异，这种转化很容易使 8-PN 暴露量增加 10 倍。因此，啤酒花提取物效率的差异可能是由于肠道代谢的差异造成的。基于这一科学知识，开发了一种创新策略来降低这种变异性。首先，从复杂的肠道生态系统中分离出能够迅速将所有 IX 代谢为 8-PN 的 Eubacterium limosum。然后，利用这种细菌开发了新一代的啤酒花产品，提高了效果的可靠性。该策略涉及将细菌作为益生菌使用，即将细菌与原始啤酒花提取物一起给药。这导致在原本不含有合适细菌的个体中也能有效地在肠道中产生 8-PN。因此，本文综述中提出的发现可以被认为是一个典型的例子，即对复杂微生物群落和单个细菌物种的特定代谢潜力有良好的了解，可能为管理和调节微生物组织向特定代谢功能提供重要机会。
