## 4 Discussion  
Due to low lipid solubility and poor stability, the utilization rate of EGCG is negligible [14]. In recent years, a new method regarding the co-encapsulation of nutrients  
Figure 6: The combination of EGCG and LP.P101 modulated the relative abundance of bacteria and affected the signal expression. **(A)** Relative abundance of different species. a-\(\ddagger\): relative abundance of _Alloprerotella_, _uncultured bacterium f Muribiculaceae_, _Bluatia_, _Bacteroides_, _Alistipes_, _Ruminiclostridium 9_, _Prevoltaceae UCG-001_, _Lactobacillus_, _Akkermans_ and _Roseburia_. Data were expressed as mean \(\pm\) SD. *\(p\) < 0.05, **\(p\) < 0.01 vs. control group; *\(p\) < 0.05, **\(p\) < 0.01, ***\(p\) < 0.001 vs. model group. **(B)** Differential analysis of Kyoto encyclopedia of genes and genomes between the model and P + E group. **(C)** [PERSON]’s correlation analysis between biochemical parameters and the relative abundance of gut microbiota species. The color ranged from blue to red and indicated the change in correlation from negative to positive. Data were expressed as mean \(\pm\) SD. *\(p\) < 0.05, **\(p\) < 0.01, ***\(p\) < 0.001.  
and probiotics, which may improve their bioavailability and function, has attracted the attention of researchers [15]. The probiotics contribute to the release of smaller molecules from the bioactive compounds to allow for a maximum utilization. For example, _Lactobacillus thammosus_ GG converted cranberry proanthocyanins and produced additional active substances that enhanced their anticancer activity [16]. Therefore, we were inspired to combine the catechins and probiotics, two inexpensive and readily available materials, to explore their enhanced properties in liver damage reduction. We screened a strain of _Lactiplantiobacillus plantarum_ from Chinese homemade sauerkraut, named LPP101 that has excellent antioxidant property, high safety and could survive in simulated gastric and intestinal fluid. When LPP101 was cultured in EGCG-MRS liquid medium, the growth of LPP101 were not affected (Figure 1B), which demonstrated that LPP101 could coexist with EGCG. Interestingly, a better weight maintenance was evidenced by the consistent body weight in the combination group (Figure 2A). Furthermore, the increscent liver coefficient as well as inflammatory infiltration and cell degeneration caused by CCl4 have been reported [13; 17], and our results are consistent with them (Figure 2B-C). As expected, CCl4 caused a significant increase of ALP (Figure 2D). Noteworthily, ALT exists in hepatocyte cytoplasm and AST is present in the mitochondria of hepatocyte. According to the report [18], mild hepatitis caused by CCl4 was manifested as hepatocyte damage and relatively complete mitochondria structure led to an increase of ALT/AST ratio, which was similar to our result (Figure 2G). Interestingly, the ratio of ALT/AST was decreased significantly in the combination group, and implied the alleviation effect of EGCG with the synergism of LPP101 (Figure 2G). Peroxidation products MDA (Figure 3F), produced after the treatment with CCl4, caused the release of antioxidant enzymes to maintain the balance of oxidative stress (Table S4). However, at the transcriptional level, the classical antioxidative signaling pathway _Nrf2/Kap1_, inhibited in model group (Figure 3H), suggested CCl4 caused oxidative damage in the liver. The combination of EGCG and LPP101 was shown to be more effective than LPP101 or EGCG alone in the recovery of antioxidative gene expression level. Furthermore, oxidative damage is always accompanied by inflammation [19]. Results showed that _Nf_-x_B_ was activated by CCl4, and the content of TNF-_x_, IL-1B and IL-6 was increased in the liver. It could be reversed by the combination of EGCG and LPP101s (Figure 3). In summary, the combination of EGCG and LPP101 were more effective in alleviating liver injury caused by CCl4. Based on the above results, we proved that the combination group had a better prevention effect on liver injury.