Unravelling the antimicrobial and antioxidant potential in Shidiaolan, a Hmong medicinal plant: A multi-technology strategy integrating UPLC fingerprinting, chemometrics, molecular docking, and response surface optimization

Shidiaolan (SDL) is a medicinal plant traditionally used in the Hmong region for its antimicrobial and antioxidant properties, though its active constituents remain undefined. Ultra performance liquid chromatography (UPLC) fingerprinting results indicated that 28 SDL batches exhibited similar compositional profiles and stable peak clusters. SDL exhibited minimum inhibitory concentration (MIC) values of 12.5-400 mg mL
-1
against
Staphylococcus capitatus
(SC) and 6.25-400 mg mL
-1
against
Candida albicans
(CA), with corresponding minimum bactericidal concentration (MBC) values of 400 mg mL
-1
and 200 mg mL
-1
, respectively. The batch inhibition results showed that S1, S6, and S10 had no inhibitory effect on SC, and S10 had no inhibitory effect on CA, while the remaining batches exhibited inhibitory effects against both bacterial strains. Spectral potency analysis identified bacteriostatic active ingredient groups in SC as F2, F8, F10, F12, and F13, and in CA as F8 and F13. Molecular docking results demonstrated low binding energy between the drug moiety and the protein, generating five interaction forces that indicate strong affinity and a stable binding conformation. The active ingredient exerted its inhibitory effect through various amino acid residues such as valine, asparagine, and aspartic acid. The antibacterial active ingredients have been classified into flavonoid and polyphenol components. After optimizing the extraction process for both components, the total flavonoid content (TFC) extracted from SDL was 15.968 mg g
-1
, and the total polyphenol content (TPC) was 15.867 mg g
-1
. Furthermore, batch extracts of both TFC and TPC demonstrated antioxidant capacity in 2,2-Diphenyl-1-picrylhydrazyl (DPPH) and 2, 2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) assays.