Exploring the anti-biofilm activity of cinnamic acid derivatives in Candida albicans

Some compounds, characterized by phenylethenyl moiety, such as methyl cinnamate and caffeic acid phenethyl ester, are able to inhibit C. albicans biofilm formation. On these bases, and as a consequence of our previous work, we synthesized a series of cinnamoyl ester and amide derivatives in order to evaluate them for the activity against C. albicans biofilm and planktonically grown cells. The most active compounds 7 and 8 showed ⩾50% biofilm inhibition concentrations (BMIC50) of 2 μg/mL and 4 μg/mL respectively, against C. albicans biofilm formation; otherwise, 7 showed an interesting activity also against mature biofilm, with BMIC50 of 8 μg/m

[Antimicrobial characteristics of a tincture of dequalinium chloride].

Dequalinium is a quaternary ammonium salt. From about 30 years Dequalinium (D.C.) was used in the treatment of the initial respiratory organs infections. It can be given orally and topically yet it cannot be given systemically cause its probable systemic toxicity. D.C. has a wide range of antimicrobial activity that is extended to Gram positive, Gram negative bacteria, protozoa and yeast. Its mechanism of action is directed to the cytoplasmatic membrane where D.C. caused its damage and consequently release of cellular components. Our study has been evaluated the antimicrobial activity of D.C. both as commercial product that pure substance. We tested 27 Gram positive bacteria, 49 Gram negative bacteria, 83 strains of fungi, we also tested the antimicrobial activity of D.C. commercial product and pure substance against 8 strains of protozoa; Trichomonas vaginalis. The antimicrobial activity was estimated in some experimental conditions, (cultural and no cultural conditions); in these experiments we can observed that the commercial product presents higher activity than pure substance. In cultural condition commercial product presents antimicrobial activity against Gram positive and negative bacteria and yeast; its interesting to evaluate that bacteria, that are resistant to the common antimicrobial agents were inhibited by D.C. tinture and pure substances. Our data exhibit that serum didn't interfere until the 2\% concentration with the antimicrobial activity of D.C., moreover this antimicrobial activity is not influenced by the inoculum size until 10(5) cell/ml. D.C. presents higher activity at alkaline pH than acid pH but strains of C. albicans were killed by D.C. at acid pH. In no cultural conditions D.C. has demonstrated a rapid antimicrobial activity in short contact time (15 minute); the cells of some microorganisms were killed in 60 minutes. Against mycelial form, the commercial product demonstrates good activity higher than pure substance. The activity of D.C. against the formation of germ-tube from blastospores of C. albicans in N-acetyl-glucosamine solution (no culture medium) was markedly high; this is very important because in C. albicans the germ-tube production and yeast-mycelial conversion are prominent for pathogenicity and resistance to host defences. Our data demonstrate the good activity of D.C. against Trichomonas vaginalis; we can also observed that the antimicrobial activity of commercial product is higher than pure substance.(ABSTRACT TRUNCATED AT 400 WORDS

GLYCOGEN MEDIUM, ANTITRICHOMONAL DRUG ACTIVITY IN VAGINAL LIQUIDS

The amount of glycogen in vaginal liquids decreases with Trichomonas vaginalis and this is connected with T. vaginalis activity in specimens. A glycogen-hydrolysed caseine medium ('glycogen medium') added to vaginal liquid is a valid maintenance medium for T. vaginalis and therefore enables a direct test for antitrichomonas drugs to be performed

[Antimicrobial activity exerted by sodium dichloroisocyanurate].

Sodium dichloroisocyanurate is a chlorinated cleaner. It was used for swimming pool sanitation and for the sterilisation of linen. Not recently ago sodium dichloroisocyanurate has substituted hypochlorite for the sterilisation of infant feeding bottles and teats. Sodium dichloroisocyanurate is soluble in water; this condition causes the hydrolysis of sodium dichloroisocyanurate in hypochlorous acid, that is the active agent, isocyanurate and isocyanurate chlorine. These compounds form a chlorine protein that carry out microbicidal activity. In a toxicology study has been shown that no severe changes in the normal metabolic function occurred, furthermore sodium dichloroisocyanurate has not shown teratogenic effects at the concentration of 200 mg/kg. The antimicrobial activity of sodium dichloroisocyanurate was evaluated against Gram negative bacteria such as E. coli or Salmonella typhimurium and against some fungi. This study illustrates a rapid antimicrobial activity using concentrations. Our study concentrated on the antimicrobial activity of sodium dichloroisocyanurate in some experimental conditions. We tested 66 strains of fungi, 28 Gram positive bacteria and 29 Gram negative bacteria. We also evaluated the antimicrobial activity of sodium dichloroisocyanurate against protozoa such as Trichomonas vaginalis. The antimicrobial activity was evaluated in cultural conditions and non cultural conditions; in these experiments we observed similar action in both the commercial product and pure substance. In cultural conditions sodium dichloroisocyanurate shows a good activity against fungi and bacteria, moreover it can be observed that the serum didn't interfere with its activity. In a non cultural condition the Candida was killed rapidly by the sodium dichloroisocyanurate but this activity is influenced by the growth phase of the yeast. Against mycelial form such as Penicillium and Aspergillus the sodium dichloroisocyanurate needs a longer contact time than yeast form for its activity. It is interesting to note that well known bacteria, that are resistant to the common antimicrobial agents, such as Pseudomonas aeruginosa, were inhibited by sodium dichloroisocyanurate in a rapid bactericidal action. Our data demonstrates that no significant adverse influence on the activity of sodium dichloroisocyanurate was shown by pH and by temperature even if in some experimental conditions increased activity was noticed at pH = 6.6. The sodium dichloroisocyanurate has demonstrated good activity against Trichomonas vaginalis. This fact extends the broad-spectrum activity of sodium dichloroisocyanurate to the protozoa. In conclusion, sodium dichloroisocyanurate has demonstrated a good activity against all tested strains, furthermore its activity did not decrease in the presence of 1\% of organic substance (serum etc.).(ABSTRACT TRUNCATED AT 400 WORDS

THE INHIBITORY-ACTION OF FLUCONAZOLE ON YEAST-TO-MYCELIAL PHASE CONVERSION IN CANDIDA-ALBICANS

The ability of fluconazole, a bis-triazole antifungal agent, to inhibit conversion of Candida albicans from the yeast (Y) to the pathogenic mycelial (M) form was studied under various in vitro cultural conditions. In growth-supporting media, fluconazole was able to inhibit Y to M conversion of the test organism at concentrations below those required to inhibit Y phase growth. Under nongrowth-supporting conditions (N-acetylglucosamine solution) fluconazole had only a small effect on Y to M conversion

Synthesis of cyclic imides (methylphtalimides, carboxylic acid phtalimides and itaconimides) and evaluation of their antifungal potential

Background: This paper describes the synthesis of three different subfamilies of cyclic imides: methylphtalimides, carboxyl acid phtalimides and itaconimides. Methods: Fifteen compounds (five of each sub-family) were obtained by the reaction of appropriated anhydrides and different aromatic amines, using the manual Topliss method. Their structures were confirmed by spectral data (IR and NMR). The antifungal activity of the synthesized compounds was investigated by broth microdilution to determine the minimal inhibitory concentration (MIC). The ability to inhibit the biofilm formation or destroy mature Candida albicans biofilm was also evaluated for the most active substances. Results: The results indicated that only the itaconimides 11-15 exhibited potent and promising antifungal properties, with MIC100 between 1 and 64 mu g mL(-1), being several times more potent than the reference drug, Fluconazole. Compounds 11-15 inhibited between 64% and 95% of biofilm formation, and destroyed between 78% and 99% of mature biofilm at a concentration of 64 mu g mL(-1). ADME (absorption, distribution, metabolism and excretion) in silico evaluations were carried out to predict whether the molecules under study are good drug candidates. Conclusions: Itaconimides appear to be promising and relevant as tools for the future development of new and effective medicinal agents to treat fungal diseases