1426Current Topics in Medicinal Chemistry, 2018, Vol. 18, No. 17 Editorial EDITORIAL Synthesis and Biological Profiles of 1,2,3-Triazole Scaffold Heterocyclic rings are considered the pillars of medicinal chemistry be- cause they are merged into the molecular structure of most of the available therapeutic drugs in the market. Since the early days of medicinal chemistry, these rings were known to be important as structural feature responsible for the relationship between structure and biological activities. Taylor et al. [1] estimated that approximately six new ring systems are created per year and that some of these are incorporated into new drugs. According to the authors, 1,2,4 and 1,2,3-triazoles are among the top 100 most frequently used ring sys- tems from small molecule drugs listed in the FDA orange book sorted by de- scending frequency. The sub-class of five-membered heterocycle [2-4] is widespread in nature [5] as well as in the therapeutic arsenal available to treat various diseases [6]. In addition, they have several representative drugs in the market for the treatment of disease as antifungal, anticancer, antiviral, β-lactamase inhibi- tor, anticonvulsant and antibiotic agents [7-11]. This special issue is based on seven manuscripts dealing with recent advances in the application of triazoles derivatives for treatment against infectious disease. Forezi et al. [12] reported a review covering synthetic methods that give access to other variations around the 1,2,3-triazole core. The systematic arrangement in this review explores the possibility of providing practical guidance to alternatives of this heterocycle. It has been divided into sections ac- cording to the types of starting materials and reactions. Heterocyclic rings having nitrogen atoms are the molecular fragments mostly used in drug design by using the tools of medicinal chemistry. Souza and colleagues [13] synthesized a series of naphthotriazolyl-4-oxoquinolines that exhibited potent in vitro an- tileishmanial activity involving at least two different mechanisms of action, making them promising lead compounds for the development of new therapeutic alternatives for leishmaniasis. Branco and coworkers [14] synthesized a series of naphthotriazolyl-4-oxoquinoline derivatives and tested their activity against a human breast cancer cell line. Among the compounds tested, a molecule was identified that killed the human breast cancer cell line MCF-7 with minimal effects on its healthy cell MCF10A. The selectivity observed against breast cancer cells make the molecule 12c a potential candidate as a novel anticancer drug. The antitumor mechanism involves the inhibition of glycolysis, diminished intracellular ATP levels, induction of ROS production and triggering of apoptosis. These effects are all selective for cancer cells, since the healthy cells are unaffected, and these effects can only be attributed to the whole molecule since different groups do not reproduce the effects. Reis and coworkers [15] prepared a series of symmetrical 1,4-disubstituted bis-1,2,3-triazoles by double Copper Catalyzed Azide-Alkyne Cycloaddition (CuAAC) from aliphatic bis-azides and a tetraethylene glycol bis-azide derivative. The novel compounds were evaluated in vitro for their cytotoxic activity against two human tumor cell lines: human breast adenocarci- noma (MDA-MB 231) and ovarian adenocarcinoma (TOV-21G). The results showed that some compounds exhibited a better selectivity index and cell viability comparable with the standard drug doxorubicin. These compounds induced apoptosis in both tested cell lines. The results suggest that these compounds may be promising prototypes for antitumor agents. Imbroisi-Filho and coworkers [16] tested several novel triazoles compounds for their putative anticancer activity and one molecule (DAN94) presented selective effects on cancer cells with minimal effects on non-cancer cells. The anticancer effect occurs through the disruption of mitochondrial potential which induced the production of ROS, triggering cell apoptosis. In parallel, cells are arrested on G1/G0 phase of the cell cycle, decreasing the ability of these cells to proliferate. On top of that, when administered to mice with xenograft tumors, DAN94 strongly reduced tumor growth with no toxic effect. These results suggested that DAN94 is a good candidate for anticancer drug due to its selective effects on cancer cells and should be tested in a pre-clinical trial. Costa et. al. [17] synthesized two series of the compounds containing 1,2,3-triazoles ring in their structures and biologically evaluated novel inhibitors of HIV Reverse Transcriptase (RT). The results of the biological evaluation showed that all com- pounds presented high RT inhibition values and lower or comparable inhibitory concentrations. Thus, new compounds could be considered lead compounds for the development of new antiretroviral compounds. Lal and coworkers [18] synthetized sixteen new hybrids and were tested in vitro for their antimicrobial activity. Some of the tested compounds exhibited promising antimicrobial activity and could be utilized for the development of the new and more potent antimicrobial drugs. F.C. da Silva L.S.M. Forezi 1873-4294/18 $58.00+.00 © 2018 Bentham Science Publishers