Tuberculosis (TB) is one of the most fatal diseases and is responsible for the infection of millions of people around the world. Most recently, scientific frontiers have been engaged to develop new drugs that can overcome drug-resistant TB. Following this direction, using a designed scaffold based on the combination of two separate pharmacophoric groups, a series of menadione-derived selenoesters was developed with good yields. All products were evaluated for their in vitro activity against Mycobacterium tuberculosis H37Rv and attractive results were observed, especially for the compounds 8a , 8c and 8f (MICs 2.1, 8.0 and 8.1 μM, respectively). In addition, 8a , 8c and 8f demonstrated potent in vitro activity against multidrug-resistant clinical isolates (CDCT-16 and CDCT-27) with promising MIC values ranging from 0.8 to 3.1 μM. Importantly, compounds 8a and 8c were found to be non-toxic against the Vero cell line. The SI value of 8a (>23.8) was found to be comparable to that of isoniazid (>22.7), which suggests the possibility of carrying out advanced studies on this derivative. Therefore, these menadione-derived selenoesters obtained as hybrid compounds represent promising new anti-tubercular agents to overcome TB multidrug resistance.

This paper aims to present a review on the main properties of silica (SiO2), such as its water solubility, its structural aspects, as well as its application in industrial and laboratory scales and the use in chromatographic techniques as a stationary phase. Also shown are chemical modifications that may occur on the silica surface and the role of silylating agents in such situations.

This paper describes an experiment that involves the extraction of total fats from three different types of chocolate using a Soxhlet extractor and subsequent testing of their antioxidant capacity due to the presence of phenolic compounds in their composition. The experiment can be performed in a 2-hour class, in addition to being useful in Higher Education in practical classes aimed at teaching laboratory techniques of Chemistry.