Antimicrobial Effect Of Resveratrol And The Mechanism Research

Objective: Resveratrol(RES) was initially discovered as phytoalexin produced by Vitis(spermatophyte). A variety of plants can produce RES when challenged by microbial attack. Resveratrol has been reported to have a variety of healthy effects, including anti-tumor, prevention of cardiovascular system, estrogen-like, antioxidant, immune modulation, anti-inflammatory, growth inhibiting, chemical prevention, and antimicrobial. Due to there are only parum research about antimicrobial activity of RES in vitro, especially anti-fungal aim to make futher approach to antimicrobial activity and mechanism. What we choose the dermatophytes and Candida albicans biofilms may give base to promising clinical application.Part 1 Anti-dermatophytes activity of Resveratrol and Mechanism ResearchMethods: Using the microdilution protocol of CLSI M38-A, to obtain Minimal inhibitory concentrations(MIC) of RES on Microsporum lanosum(M.l), Microsporum gypseum(M.g), Epidermophyton floccosum(E.f) and Fusarium moniliforme(F.m). Transmission electron microscope(TEM) is used to observe the effect of RES on Ultrastructure.Results: The MIC₅₀ and MIC₉₀ of RES to M.l are 0.064 and 0.128mg/mL respectively. The MIC₅₀ and MIC₉₀ of RES to M.g are 0.128 and 0.256mg/mL respectively. The MIC₅₀ and MIC₉₀ of RES to E.f are all 0.128mg/mL. Under the highest concentration of 2.048mg/mL, there is no obvious inhibitory action on F.m. Observing through TEM, we can clearly see that the normal M.l cellular structure is integrity and clear, cell wall borderline is regularity, envelope, cell wall, plasma membrane, chromatosome are all seen clearly. After affect by 0.064mg/ml RES, some layer of cell wall is ill-defined, the structure of cell organ is thinningz, most cytoplasmic inclusion disappeared, last but not the least, there were generous vacuole emerged; As affect by 0.128mg/ml RES, all vacuolus emerged in the chondriosome. Chondriosome shows the character of pyknosis and marrowly.Experimental results indicate that RES has a good antibacterial activity on Dermatophyte. Transmission electron microscope pictures confirm the effective katogene. The effect on F.m is not fine, although under such serial experiment concentrationsPart 2 In vitro activity of Resveratrol against Candida albicans biofilmsMethods:1 To establish the Candida albicans(C.albicans) biofilms model.2 Inverted Microscopic examination and scanning electron microscope were conducted to assess the effect of resveratrol on morphogenesis of C.albicans biofilms.3 XTT reduction assay was performed to detect SMIC50 (Sessile Minimal inhibitory concertrations, SMIC ) and SMIC80 of resveratrol against C.albicans biofilms.4 Application of SPSS 13.0 statistical software package, using an independent samples t test comparison of experimental group and positive control OD.Results:1 Inverted Microscopic examination of resveratrol on morphogenesis of C.albicans biofilms: there were many yeast cells and hyphas to establish gathering biofilms. A few yeast cells and hyphas that were microsoma showing gathering state because of 0.128mg/ml RES, and there were only parum yeast cells because of 0.256mg/ml RES.2 Scanning electron microscope of resveratrol on morphogenesis of C.albicans biofilms: there were uniform and intensive fungus, a few gather conglobation on photograph of control group; at 15000 times it was clearly be seen that it had sooth cell wall, the regular fungus body, the blunt both ends, the connected extracellular slime substances among the yeast cells. There were a few showing gathering state and membranes because of RES on photograph of experiment group; at 15000 times was clearly be seen that the fungus had sinking or scarred or distorted body. There were intensive and different size on photograph of experiment group.3 SMIC₅₀ and SMIC₈₀ of resveratrol against C.albicans biofilms are 0.128,0.256mg/ml respective.4 Two groups OD differences was statistically significant (P<0.05), when RES is 0.064, 0.128, 0.256, 0.512, 1.024mg/ml respectively. There was no significant differences, when RES is 0.016, 0.032mg/ml.Conclusions:1 RES has a very good antimicrobial effect on Dermatophytes and Candida albicans biofilm under fairly low concentrations, especially to Dermatophytes. And we desire to provide foundation for clinical application and new drug research, and it may offer a new way to cure infection for clinic.2 Through the experiment we initially conclude that RES interfere 1,3-β-D-glucan synthase, mannan-proteic substance, chitin synthase and sphingolipid to hamper cell wall synthesis, meanwhile damage cellular membrane, influence the normal cell cycle and inhibit replication of material in the cell. The effect on Dermatophyte may be interact with ergosterol in the fungal cell membrane and affect selective permeability of the plasma membrane; leakage of intracellular potassium and magnesium then leads to loss of the proton gradient within the membrane and can also exert oxidative damage to the fungal plasma membrane, chondriosome and karyolemma chiefly to dissolve the cell. Or is one result of the synergistic mechanisms what we investigated above. The effect on Candida albicans biofilm may have inhibitory effects on biofilm adhesion, a potential role for portion of cell wall/surface and secreted mannoproteins in the different phases of biofilm formation. Changes in properties of cell wall/surface mannoproteins that are likely to in?uence cell–cell contacts important for the overall architecture of the biofilm changes in cell surface; cell wall or interfere synthesis of cell wall, then enter interior to cause destroy of groundplasm and cell organelle.