Antifungal Activity and Toxicity of the 3,4,5-Trihydroxybenzoic and 3,4,5-Tris(Acetyloxy)Benzoic Acids

Invasive fungal infections have been gaining notoriety due to several factors, mainly their increasing incidence in immunocompromised patients. The aim of the present study was to evaluate the antifungal activity and toxicity of the 3,4,5-trihydroxybenzoic acid (3,4,5-THB) and of its derivative, the 3,4,5-tris(acetyloxy)benzoic acid (3,4,5-TAB). The 3,4,5-THB was purchased and its derivative was obtained by purifying and characterizing performed using semisynthesis reactions (esterification), recrystallization, column chromatography and infrared analytical techniques and nuclear magnetic resonance. Minimum inhibitory concentration (MIC) and minimum lethal concentration (MLC) were determined in order to evaluate the antifungal activity of the compounds against four clinical isolates and four standard strains of Candida sp. and five clinical isolates of dermatophytes, following the Clinical and Laboratory Standards Institute protocols. The toxicity of the compounds was evaluated by determining the lethal dosis (LD50) using lethality assay of Artemia salina. The most sensitive yeasts to the 3,4,5-THB were C. albicans ATCC 10231 and C. krusei ATCC 6258, both presenting a MIC of 128 μg·mL-1. For Trichophyton sp. and Epidermophyton floccosum, the MIC was 32 μg·mL-1. The 3,4,5-TAB showed a lower inhibitory activity against Candida and dermatophyte species tested. The LD50 of 3,4,5-THB was 222.60 μg·mL-1 and the 3,4,5-TAB showed 481.69 μg·mL-1 of LD50. In conclusion, the 3,4,5-trihydroxybenzoic acid showed antifungal activity against species of medical importance, mainly dermatophytosis-causing fungi, and the 3,4,5-tris(acetyloxy)benzoic acid showed no increasing antifungal activity and toxicity in relation to the original compound.

Shift to a low carbon society through energy systems design

Concern about global warming calls for an advanced approach for designing an energy system to reduce carbon emissions as well as to secure energy security for each country.Conventional energy systems tend to introduce different technologies with high conversion efficiency,leading to a higher average efficiency.Advanced energy systems can be achieved not by an aggregate form of conversion technologies but by an innovative system design itself.The concept of LCS(low carbon society) is a unique approach having multi-dimensional considerations such as social,economic and environmental dimensions.The LCS aims at an extensive restructuring of worldwide energy supply/demand network system by not only replacing the conventional parts with the new ones,but also integrating all the necessary components and designing absolutely different energy networks.As a core tool for the LCS design,energy-economic models are applied to show feasible solutions in future with alternatives such as renewable resources,combined heat and power,and smart grid operations.Models can introduce changes in energy markets,technology learning in capacity,and penetration of innovative technologies,leading to an optimum system configuration under priority settings.The paper describes recent trials of energy models application related to waste-to-energy,clean coal,transportation and rural development.Although the modelling approach is still under investigation,the output clearly shows possible options having variety of technologies and linkages between supply and demand sides.Design of the LCS means an energy systems design with the modelling approach,which gives solution for complex systems,choices among technologies,technology feasibility,R&D targets,and what we need to start.