Anxiolytic effects of N-(4,5-dihydro-5-oxo-1,2-dithiolo-[4,3,b]-pyrrole-6-yl)-N-methylformamide, a pyrroloformamide isolated from a marine Streptomyces sp., in adult zebrafish by the 5-HT system.

General anxiety disorders are among the most prevalent mental health problems worldwide. The emergence and development of anxiety disorders can be due to genetic (30-50%) or non-genetic (50-70%) factors. Despite medical progress, available pharmacotherapies are sometimes ineffective or can cause undesirable side effects. Thus, it becomes necessary to discover new safe and effective drugs against anxiety. This study evaluated the anxiolytic effect in adult zebrafish (Danio rerio) of a natural pyrroloformamide (PFD), N-(4,5-dihydro-5-oxo-1,2-dithiolo-[4,3,b]-pyrrole-6-yl)-N-methylformamide, isolated from a Streptomyces sp. bacterium strain recovered from the ascidian Eudistoma vannamei. The complete structure of PFD was determined by a detailed NMR analysis, including 1H-13C and 1H-15N-HBMC data. In addition, conformational and DFT computational studies also were performed. A group of fishes (n = 6) was treated orally with PFD (0.1, 0.5 and 1.0 mg/mL; 20 µL) and subjected to locomotor activity and light/dark tests, as well as, acute toxicity 96 h. The involvement of the GABAergic and serotonergic (5-HT) systems was investigated using flumazenil (a silent modulator of GABA receptor) and 5-HT1, 5-HT2A/2C and 5-HTR3A/3B receptors antagonists, known as pizotifen, granisetron and cyproheptadine, respectively. PFD was nontoxic, reduced locomotor activity and promoted the anxiolytic effect in zebrafish. Flumazenil did not inhibit the anxiolytic effect of the PFD via the GABAergic system. This effect was reduced by a pretreatment with pizotifen and granisetron, and was not reversed after treatment with cyproheptadine. Molecular docking and dynamics studies confirmed the interaction of PFD with the 5-HT receptor.Communicated by Ramaswamy H. Sarma.

Pyrroloformamide (PFD), isolated from the marine Streptomyces sp. associated ascidian Eudistoma vannamei, showed no toxicity in adult zebrafish but reduced its locomotor activity.The structural elucidation of PFD was determined by the analysis of 1D and 2D NMR and HRESIMS data.The density functional theory (DFT) study confirmed the existence of two conformers as determined by NMR spectra.The serotonergic system modulated the anxiolytic effect of PFD via the 5-HT receptor in adult zebrafish.Molecular docking and dynamics studies confirmed the interaction of PFD with the 5-HT receptor.

Pharmacological potential of the triterpene 3ß,6ß,16ß-trihidroxilup-20 (29)-ene isolated from Combretum leprosum: A literature review.

Globally, plant-derived medicines have been playing an increasing and relevant role in the treatment of several diseases, thus fostering the search for new bioactive substances. Among the various families of plants studied, those of the Combretum genus can be highlighted since they are widely used in folk medicine for the treatment of hepatitis, malaria, respiratory infections, cancer, skin hemorrhage, and anxiety. Phytochemical studies carried out on species of the Combretum genus demonstrated the presence of several classes of bioactive chemical compounds, including the triterpene 3ß,6ß,16ß-trihydroxilup-20(29)-ene (CLF-1). In this perspective, the objective of this review was to gather all pharmacological activities attributed to the CLF-1 triterpene, highlighting its importance for the pharmaceutical industry. The research was performed in scientific databases such as PubMed, SciELO, LILACS, SciFinder and Science Direct. The literature indicates a great pharmacological potential of CLF-1, evidencing its antioxidant, anti-inflammatory, antiviral, antiparasitic, antinociceptive, healing, and antibacterial action, antinociceptive and antitumor effect. Therefore, based on the different research above, it is plausible to consider CLF-1, obtained from different parts of the C. leprosum plant, as a molecule with biotechnological potential that may contribute to the development of new drugs and, consequently, in the treatment of various human pathologies.

Antiproliferative activity on Trypanosoma cruzi (Y strain) of the triterpene 3ß,6ß,16ß-trihidroxilup-20 (29)-ene isolated from Combretum leprosum.

Chagas disease infects approximately seven million people worldwide. Benznidazole is effective only in the acute phase of the disease, with an average cure rate of 80% between acute and recent cases. Therefore, there is an urgent need to find new bioactive substances that can be effective against parasites without causing so many complications to the host. In this study, the triterpene 3ß-6ß-16ß-trihydroxilup-20 (29)-ene (CLF-1) was isolated from Combretum leprosum, and its molecular structure was determined by NMR and infrared spectroscopy. The CLF-1 was also evaluated in vitro and in silico as potential trypanocidal agent against epimastigote and trypomastigote forms of Trypanosoma cruzi (Y strain). The CLF-1 demonstrated good results highlighted by lower IC50 (76.0 ± 8.72 µM, 75.1 ± 11.0 µM, and 70.3 ± 45.4 µM) for epimastigotes at 24, 48 and 72 h, and LC50 (71.6 ± 11.6 µM) for trypomastigotes forms. The molecular docking study shows that the CLF-1 was able to interact with important TcGAPDH residues, suggesting that this natural compound may preferentially exert its effect by compromising the glycolytic pathway in T. cruzi. The ADMET study together with the MTT results indicated that the CLF-1 is well-absorbed in the intestine and has low toxicity. Thus, this work adds new evidence that CLF-1 can potentially be used as a candidate for the development of new options for the treatment of Chagas disease.Communicated by Ramaswamy H. Sarma.