Chlorogenic acid (CA) is a natural plant-derived polyphenol compound that is widely present in beverages (coffee and tea), fruits (blueberry, apple, and mulberry), and medicinal plants (Lonicera japonica, Eucommia ulmoides, and Cichorium intybus). In recent years, CA has attracted extensive attention due to its various health benefits, such as anti-inflammatory, immunomodulatory, anti-obesity, anti-diabetes mellitus, and neuroprotection activities. Interestingly, the low bioavailability of CA corresponds to high bioactivity, which raises a key scientific question of how low bioavailability CA can achieve high biological activity. In this review, we highlight the gut microbiota as a key target for connecting the two by summarizing a large amount of evidence. Specifically, the composition and abundance of gut microbiota, its metabolites, intestinal immunity, barrier function and so on were all changed under different pathological conditions such as inflammatory bowel disease, liver disease, kidney disease, cardiovascular disease, diabetes mellitus, obesity, etc. Conversely, these changes could be reversed by CA. In a word, CA could achieve pharmacological activity as well as health-protective effects by modulating intestinal immune and barrier function, gut microbiota composition, gut microbiota metabolites, and signaling pathways. This review provides new targets for the prevention and treatment of diseases by CA. Meanwhile, regulating the composition of the gut microbiota through natural products may be a potential strategy to achieve health protection.

As a traditional Chinese herbal medicine, Schisandrae Chinensis Fructus (SC) has been used in medicine and food industry due to its health care and therapeutic effects. Over the past 20 years, the use of SC and its active ingredient lignans in the prevention and treatment of liver diseases has been increasing, and their hepatoprotective effects has increased the interest of the public and academia. Therefore, in the present work, we first determined the effectiveness of SC in the treatment of liver diseases such as metabolic associated fatty liver disease, alcoholic liver disease, cholestatic liver disease and acute liver injury. Subsequently, the pharmacological effects and molecular mechanisms of lignans, the active components of SC, for liver disease treatment were comprehensively summarized for the first time. The results showed that the lignans in SC could achieve hepatoprotective effects by regulating lipid metabolism, anti-fibrosis, anti-inflammation, anti-oxidation, anti-tumor and regulating bile acid metabolism. The mechanism mainly involved  adenosine 5‘-monophosphate-activated protein kinase, endoplasmic reticulum stress,  sterol regulatory element binding protein 1c, autophagy, transforming growth factor-β, mitogen-activated protein kinase, microRNA, nuclear factor kappa-B, nuclear factor erythroid-2-related factor 2, heat shock proteins and pregnane X receptor signaling pathways. These results can lay a scientific foundation for the development of hepatoprotective drugs or functional foods from SC/lignans.