Key components responsible for the antibacterial activity of Metagentiana rhodantha (Franch.) T.N.Ho & S.W.Liu—an in vitro and in vivo study based on spectrum-effect relationship and computer simulations

Metagentiana rhodantha (Franch.) T.N.Ho & S.W.Liu (Gentianaceae) is a medicinal plant widely used in traditional ethnomedicine for "clearing heat and detoxification," yet its antibacterial constituents and mechanisms remain unclear. This study integrated spectrum-effect analysis, molecular docking, and in vivo assays to identify key bioactive components and validate therapeutic efficacy for skin infections. The 70% methanol extract exhibited broad-spectrum antibacterial activity (MIC: 0.0625-0.125 g/mL) while maintaining low cytotoxicity in L929 murine fibroblasts. Spectrum-effect analysis identified flavonoids, particularly mangiferin and isoorientin, as the principal active constituents. Molecular docking simulations suggested these compounds target bacterial glycogen synthase (binding energy: -9.7 to -10.8 kcal/mol). In a Staphylococcus aureus-induced skin infection mouse model, topical application significantly accelerated wound healing (72.1% closure vs. 31.0% in controls, p < 0.01) and alleviated inflammation. These findings provide scientific validation for using M. rhodantha as a topical antibacterial agent.