Synergistic effects and related bioactive mechanisms of <italic>Potentilla fruticosa Linn.</italic> leaves combined with green tea polyphenols studied with microbial test system (MTS).

Previous research found <italic>Potentilla fruticosa</italic> leaf extracts (PFE) combined with green tea polyphenols (GTP) showed obvious synergistic effects based on chemical mechanisms. This study further confirmed the synergy of PFE + GTP viewed from bioactivities using the microbial test system (MTS). The MTS antioxidant activity results showed the combination of PFE + GTP exhibited synergistic effect and the ratio 3:1 showed the strongest synergy, which were in accordance with the results in H₂O₂ production rate. The combination of PFE + GTP promoted CAT and SOD enzyme activity and their gene expression especially at the ratio 3:1. Therefore, the synergism of PFE + GTP may be due to the promotion of CAT and SOD genes expression which enhanced the CAT and SOD enzyme activities. These results confirmed the synergy of PFE + GTP and could provide theoretical basis to produce a compounded tea made of a mixture of leaves from <italic>Potentilla</italic> species. [ABSTRACT FROM AUTHOR]