## 3 Results
### Gut Microbiota Analysis  
Bioactive compounds from herbal tea such as polyphenols and polysaccharides could be utilized by gut microbiota without breaking down in the digestion process. To compare gut microbiota between healthy subjects (RC) and healthy subjects with voluntary daily herbal intake (Rh), a pilot study was carried out using herbal tea made from the herbal decoction that underwent inoculated fermentation (IF, group #4). It possessed the best performance from above evaluations. The top 5 phyla and top 20 genera with high relative abundance based on the selection criteria LDA > 2, \(p\) < 0.05 are shown in Figure 7.  
Figure 6: Antioxidative profiles of herbal broths from all four treatments. The data represent the means \(\pm\) SD (\(n\) = 3). \(\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{ \texttt{\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{\texttt{ \texttt{  \texttt{   }}}}}}}}}}}}}}\), \(p\) < 0.01.  
Figure 7: Comparison of the gut microbiota by the relative abundances at the phylum (**a**) and genus level (**b**).  
At the phylum level (Figure 7a), the relative abundance of major microbiota in RC were _Bacteroides_ (30.88%) and _Firmicutes_ (59.58%). With the herbal intake, it brought more _Bacteroides_ (40.99%) and fewer _Firmicutes_ (50.00%). The _Firmicutes_ to _Bacteroides_ (F/B) ratio was 1.93 in the RC group and reduced to 1.22 in the Rh group. The F/B ratio is frequently considered as a relevant marker of intestinal health or dysbiosis [44]. _Actinobacteria_ decreased from 5.20% in the RC group to 3.99% in the Rh group. As _Firmicutes_ absorb more calories from food than _Bacteroidetes_, a reduced F/B ratio in the Rh group indicated a beneficial effect of herbal tea intake. _Bacteroidetes_ could promote health through breaking down brown fat in the system [45]. The majority _Firmicutes_ and _Bacteroidetes_, together with the minority _Actinobacteria_, maintain gut homeostasis at the taxonomic level [46]. Elevated proportions of _Proteobacteria_ (4.37%) in the Rh group, compared with that in the RC group (1.49%), suggested a greater involvement at the genetic level, since low abundant _Proteobacteria_ tend to keep gut function healthy through variable genes [47].  
At the genus level (Figure 7b), the Rh group showed decreased relative abundance in the seven genera of _Atopostipes_, _Bifidobacterium_, _Lactobacillus_, _Sporosarcina_, _Akkermansia_, _Prerotella_, and _Coprococcus_, compared to that of the RC group. Research has proven that _Atopostipes_, _Sporosarcina_[48], _Akkermansia_[49], _Bifidobacterium_[50], _Lactobacillus_[51], _Precotella_[52], and _Coprococcus_[53] are all beneficial for enhancing gut health. Three genera of _Allobaculum_, _Jeotgalcoccus_, and _Turicibacter_ in the Rh group showed the most elevated relative abundance. _Allobaculum_ produces short-chain fatty acids of lactic and butyrate acids, which offers a protection for the intestinal barrier [54]. The genera of both _Jeotgalcoccus_ and _Turicibacter_ were associated with fatty acid degradation in the host [55; 56]. Based on these alterations in the gut microbiota, the influence of fermented herbal decoction on the host metabolism is interesting and needs to be further investigated.