The human intestine contains an intricate ecological community of bacteria, referred as the gut microbiota, which plays a pivotal role in the host homeostasis. Multiple factors could interfere with this delicate balance, thus causing a disruption of the microbiota equilibrium, the so called dysbiosis. Gut microbiota dysbiosis is involved in gastrointestinal and extra-intestinal metabolic diseases, as obesity and diabetes. Polyphenols, present in a broad range of plant foods, are known to have numerous health benefits; however, their beneficial effect on pre-existing dysbiosis is less clear. Indeed, in most of the conducted animal studies the administration of polyphenols or foods rich in polyphenols occurred simultaneously with the induction of the pathology to be examined, then analyzing the preventive action of the polyphenols on the onset of dysbiosis, while very low studies analyzed the modulatory activity of polyphenols on the pre-existing dysbiosis. For this reason, the present review aims to update the current information about the modulation of the pre-established gut microbiota dysbiosis by dietary phenolic compounds in a broad range of disorders in both animal studies and human trials, distinguishing the preventive or treatment approaches in animal studies. The described studies highlight that dietary polyphenols, exerting prebiotic-like effects, can modulate the pre-existing dysbiosis stimulating the growth of beneficial bacteria and inhibiting pathogenic bacteria in both animal models and humans. Anyway, most of the conducted studies are related to obesity and metabolic syndrome, and so further studies are needed to understand this polyphenols' ability in relation to other pathologies.

中文翻译：

---

多酚作为预先确定的肠道微生物群失调的调节剂：最先进的

人体肠道包含一个复杂的细菌生态群落，称为肠道微生物群，在宿主体内平衡中起着关键作用。多种因素可能会干扰这种微妙的平衡，从而导致微生物群平衡的破坏，即所谓的生态失调。肠道菌群失调与肥胖和糖尿病等胃肠道和肠外代谢疾病有关。众所周知，多酚存在于多种植物性食物中，具有许多健康益处；然而，它们对预先存在的生态失调的有益作用尚不清楚。事实上，在大多数进行的动物研究中，多酚或富含多酚的食物的给药与诱导要检查的病理学同时发生，然后分析多酚对生态失调的预防作用，而非常低的研究分析了多酚对预先存在的生态失调的调节活性。出于这个原因，本综述旨在更新有关在动物研究和人体试验中广泛的疾病中膳食酚类化合物调节预先确定的肠道微生物群失调的当前信息，区分动物的预防或治疗方法学习。所描述的研究强调，在动物模型和人类中，具有益生元样作用的膳食多酚可以调节预先存在的生态失调，刺激有益细菌的生长并抑制病原菌。无论如何，大多数进行的研究都与肥胖和代谢综合征有关，