[Integrated analysis of molecular docking and metabolomics on the anti-candida albicans biofilm mechanism of proanthocyanidins].

To screen out potential ligands of Agglutinin-like sequence protein 3 (ALS3) with anti-adhesion from the candidate drug library. To clarify the antibacterial and anti-biofilm activities of proanthocyanidins (PAC) and conduct a preliminary exploration of their metabolomics mechanisms. From January to December in 2023, at the Laboratory Department of Guiyang Maternal and Child Health Hospital,using ALS3 as the target protein, the molecular docking virtual screening method was adopted to screen out ALS3 inhibitors with potential resistance to biofilm formation. The minimal inhibitory concentration (MIC) and minimal fungicidal concentration (MFC) of PAC for Candida albicans were determined by the micro-liquid-based dilution method, and the time-growth curve was plotted to explore the antibacterial activity of PAC for Candida albicans. The XTT[2, 3-bis(2-methoxy-4-nitro-5-sulfophenyl)-2H-tetrazolium-5-carboxanilide] staining method was used to explore the formation of Candida albicans biofilms by PAC and its dispersal effect on the formation of mature biofilms within 24 hours. The metabolites of Candida albicans after the action of PAC were identified by liquid chromatography-mass spectrometry. Multivariate analysis (principal component analysis and partial least squares discriminant analysis) and univariate analysis (t-test) were used to screen differential metabolites to preliminarily explore the anti-biofilm mechanism of PAC. The results showed that a total of 69 compounds were obtained through Glide's three-level screening (SP, XP, HTVS). Based on the criteria of (1) docking scores better than diazepam and (2) excluding antibiotics, PAC compounds with excellent scores and relatively promising pattern binding were obtained. The MIC of PAC is 256 μg/ml, and the MFC is 1 024 μg/ml, showing a time-dose dependence. The concentration of PAC with a 50% inhibition rate on Candida albicans biofilm is 256 μg/ml(one-way analysis of variance, F=15.92,P<0.001). When the concentration reaches 1 024 μg/ml, PAC can inhibit 80% of Candida albicans biofilm formation(One-way analysis of variance, F=15.92,P<0.001).For mature Candida albicans biofilms, when the PAC concentration reaches 1 024 μg/ml, it exhibits a dispersal effect on approximately 40% of the biofilm.(One-way analysis of variance, F=5.01,P=0.002). The results of non-targeted metabolomics indicated that compared with the untreated control group, the total number of differential metabolites of Candida albicans under the action of PAC was 350, among which 119 were up-regulated and 231 were down-regulated. The significantly changed differential metabolites include: 5-hydroxypiperidinic acid, Rhodamine 123, allantoin, indolebutyric acid, thiamine, etc.The main metabolic pathways enriched by differential metabolites are: global and overview maps, carbohydrate metabolism, membrane transport systems, lipid metabolism, cofactor and vitamin metabolism, nucleotide metabolism, and amino acid metabolism. In conclusion,it is feasible to use ALS3 as the target and a virtual screening method to search for the hit compounds of anti-Candida albicans biofilms. PAC was revealed to be an inhibitor targeting ALS3 in Candida albicans, and its anti-biofilm mechanism is associated with disturbances in energy metabolism, nucleic acid synthesis, membrane structure disruption, and enhanced oxidative stress.