Drug repositioning in the COVID-19 pandemic: fundamentals, synthetic routes, and overview of clinical studies.

Introduction: Drug repositioning is a strategy to identify a new therapeutic indication for molecules that have been approved for other conditions, aiming to speed up the traditional drug development process and reduce its costs. The high prevalence and incidence of coronavirus disease 2019 (COVID-19) underline the importance of searching for a safe and effective treatment for the disease, and drug repositioning is the most rational strategy to achieve this goal in a short period of time. Another advantage of repositioning is the fact that these compounds already have established synthetic routes, which facilitates their production at the industrial level.

To be drug or prodrug: structure-property exploratory approach regarding oral bioavailability.

Purpose: Prodrug design is a strategy that can be used to adjust physicochemical properties of drugs in order to overcome pharmacokinetic problems, such as poor oral bioavailability. However, Lipinski´s and Veber´s rules predict whether compounds will have absorption problems even before the design of prodrugs. In this context, our goal was to evaluate the molecular properties which most influenced the absorption process of prodrugs compared to its precursor through exploratory data analysis approach.

Dillapiole as antileishmanial agent: discovery, cytotoxic activity and preliminary SAR studies of dillapiole analogues.

In this paper, the isolation of dillapiole (1) from Piper aduncum was reported as well as the semi-synthesis of two phenylpropanoid derivatives [di-hydrodillapiole (2), isodillapiole (3)], via reduction and isomerization reactions. Also, the compounds' molecular properties (structural, electronic, hydrophobic, and steric) were calculated and investigated to establish some preliminary structure-activity relationships (SAR). Compounds were evaluated for in vitro antileishmanial activity and cytotoxic effects on fibroblast cells.

The anti-inflammatory activity of dillapiole and some semisynthetic analogues.

Context: Piper aduncum L. (Piperaceae) produces an essential oil (dillapiole) with great exploitative potential and it has proven effects against traditional cultures of phytopathogens, such as fungi, bacteria and mollusks, as well as analgesic action with low levels of toxicity.

Objective: This study investigated the in vivo anti-inflammatory activity of dillapiole.

Synthesis and in vitro evaluation of potential antichagasic hydroxymethylnitrofurazone (NFOH-121): a new nitrofurazone prodrug.

The synthesis of mutual prodrugs of nitrofurazone with primaquine, using specific and nonspecific spacer groups, has been previously attempted seeking selective antichagasic agents. The intermediate reaction product, hydroxymethylnitrofurazone (NFOH-121), was isolated and tested in LLC-MK(2) culture cells infected with trypomastigotes forms of Trypanosoma cruzi showing higher trypanocidal activity than nitrofurazone and benznidazol in all stages. The mutagenicity tests showed that the prodrug was less toxic than the parent drug.