Exploring the antileishmanial activity of dicentrine from Ocotea puberula (Lauraceae) using biomembrane models.

This study aimed to assess the antiprotozoal efficacy of dicentrine, an aporphine alkaloid isolated from Ocotea puberula, against amastigote forms of Leishmania (L.) infantum. Our findings reveal that dicentrine demonstrated a notable EC50 value of 10.3 µM, comparable to the positive control miltefosine (EC50 of 10.4 µM), while maintaining moderate toxicity to macrophages (CC50 of 51.9 µM). Utilizing an in silico methodology, dicentrine exhibited commendable adherence to various parameters, encompassing lipophilicity, water solubility, molecule size, polarity, and flexibility. Subsequently, we conducted additional investigations to unravel the mechanism of action, employing Langmuir monolayers as models for protozoan cell membranes. Tensiometry analyses unveiled that dicentrine disrupts the thermodynamic and mechanical properties of the monolayer by expanding it to higher areas and increasing the fluidity of the film. The molecular disorder was further corroborated through dilatational rheology and infrared spectroscopy. These results contribute insights into the role of dicentrine as a potential antiprotozoal drug in its interactions with cellular membranes. Beyond elucidating the mechanism of action at the plasma membrane's external surface, our study sheds light on drug-lipid interface interactions, offering implications for drug delivery and other pharmaceutical applications.

Exploring the antileishmanial activity of dicentrine from Ocotea puberula (Lauraceae) using biomembrane models

This study aimed to assess the antiprotozoal efficacy of dicentrine, an aporphine alkaloid isolated from Ocotea puberula, against amastigote forms of Leishmania (L.) infantum. Our findings reveal that dicentrine demonstrated a notable EC50 value of 10.3 μM, comparable to the positive control miltefosine (EC50 of 10.4 μM), while maintaining moderate toxicity to macrophages (CC50 of 51.9 μM). Utilizing an in silico methodology, dicentrine exhibited commendable adherence to various parameters, encompassing lipophilicity, water solubility, molecule size, polarity, and flexibility. Subsequently, we conducted additional investigations to unravel the mechanism of action, employing Langmuir monolayers as models for protozoan cell membranes. Tensiometry analyses unveiled that dicentrine disrupts the thermodynamic and mechanical properties of the monolayer by expanding it to higher areas and increasing the fluidity of the film. The molecular disorder was further corroborated through dilatational rheology and infrared spectroscopy. These results contribute insights into the role of dicentrine as a potential antiprotozoal drug in its interactions with cellular membranes. Beyond elucidating the mechanism of action at the plasma membrane's external surface, our study sheds light on drug-lipid interface interactions, offering implications for drug delivery and other pharmaceutical applications.

Differential lethal action of C17:2 and C17:0 anacardic acid derivatives in Trypanosoma cruzi - A mechanistic study.

The n-hexane extract from leaves of Schinus terebinthifolius (Anacardiaceae) induced 100% of death of trypomastigote forms of T. cruzi at 300 µg/mL and was subjected to a bioactivity-guided fractionation to afford a C17:2 derivative of anacardic acid [6-(8'Z,11'Z)-heptadecadienyl-salicylic acid, 1]. Additionally, compound 1 was subjected to hydrogenation procedures to afford a C17:0 derivative (6-heptadecanyl-salicylic acid, 1a). Compounds 1 and 1a were effective in killing trypomastigote forms of T. cruzi with IC50 values of 8.3 and 9.0 µM, respectively, while a related compound, salicylic acid, was inactive. Furthermore, no cytotoxicity was observed for the highest tested concentration (CC50 > 200 µM) for all evaluated compounds. Due to the promising results, the mechanism of parasite death was investigated for compounds 1 and 1a using flow cytometry and spectrofluorimetry. The cell membrane permeability assay with SYTOX Green indicated that compound 1 significantly altered this parameter after 40 min of incubation, while compound 1a caused no alteration. Considering that the hydrogenation rendered a differential cellular target in parasites, additional assays were performed with 1a. Despite no permeabilization of the plasma membrane, compound 1a induced depolarization of the electric potential after two hours of incubation. The mitochondria of the parasite were also affected by compound 1a, with depolarization of the mitochondrial membrane potential, and reduction of reactive oxygen species (ROS) levels. The Ca2+ levels were not affected during the time of incubation. Considering that the mitochondrion is a single organelle in Trypanosoma cruzi for ATP generation, compounds affecting the bioenergetic system are of interest for drug discovery against Trypanosomatids.