Structural improvement of compounds with analgesic activity: AC-MPF4, a compound with mixed anti-inflammatory and antinociceptive activity via opioid receptor

3D-QSAR, ADME-Tox In Silico Prediction and Molecular Docking Studies for Modeling the Analgesic Activity against Neuropathic Pain of Novel NR2B-Selective NMDA Receptor Antagonists

A new class of selective antagonists of the N-Methyl-D-Aspartate (NMDA) receptor subunit 2B have been developed using molecular modeling techniques. The three-dimensional quantitative structure–activity relationship (3D-QSAR) study, based on comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA) models, indicate that steric, electrostatic and hydrogen bond acceptor fields have a key function in the analgesic activity against neuropathic pain. The predictive accuracy of the developed CoMFA model (Q2 = 0.540, R2 = 0.980, R2 pred = 0.613) and the best CoMSIA model (Q2 = 0.665, R2 = 0.916, R2 pred = 0.701) has been successfully examined through external and internal validation. Based on ADMET in silico properties, L1, L2 and L3 ligands are non-toxic inhibitors of 1A2, 2C19 and 2C9 cytochromes, predicted to passively cross the blood–brain barrier (BBB) and have the highest probability to penetrate the central nervous system (CNS). Molecular docking results indicate that the active ligands (L1, L2 and L3) interact specifically with Phe176, Glu235, Glu236, Gln110, Asp136 and Glu178 amino acids of the transport protein encoded as 3QEL. Therefore, they could be used as analgesic drugs for the treatment of neuropathic pain.

A polysaccharide fraction from Handroanthus albus (yellow ipê) leaves with antinociceptive and anti-inflammatory activities

Handroanthus albus, commonly known as yellow ipê, is a native and widely distributed tree in Brazil. An aqueous soluble polysaccharide fraction (HASP) was obtained from its leaves, and monosaccharide composition, glycosidic linkage analysis by methylation and NMR spectroscopy indicated that HASP is mainly composed of a type II arabinogalactan, and suggested that other polysaccharides could also be present in a smaller proportion. HASP was able to promote antinociception in formalin-induced (second phase) and on glutamate-induced nociception tests, besides reducing the number of abdominal contortions induced by acetic acid in mice. Moreover, HASP reduced acetic acid-induced leukocyte infiltration in the peritoneal cavity and showed anti-edematogenic activity, decreasing mechanical allodynia and myeloperoxidase activity in the carrageenan-induced paw edema model. These results showed that the polysaccharide fraction HASP from H. albus leaves has interesting antinociceptive and anti-inflammatory activities.

Aqueous extract of dry powder blend of seeds and leaves of Picralima nitida (Stapf) T. & H. Durand reduce pain and inflammation in animal models

OBJECTIVES

Blend of seeds and leaves of Picralima nitida herein referred to as West African Durand powder (WDP) was investigated for antinociceptive and anti-inflammatory properties.

METHODS

Acute toxic effect of the aqueous extract was evaluated in mice of both sexes. Antinociceptive effect of WDP (100-400 mg/kg) was evaluated in models of acetic acid-induced writhing and thermal nociception on hot plate in mice. Carrageenan-induced paw oedema and air pouch rat models were used to evaluate the anti-inflammatory activity of the extract.

RESULTS

WDP (2,000 mg/kg) showed no toxic effect in mice. WDP at 100, 200 and 400 mg/kg inhibited abdominal writhings by 59.9, 66.0 and 79.0%, respectively. There was a significant increase in reaction time on the hot plate tests in mice treated with WDP (400 mg/kg). The paw oedema was reduced by WDP (100, 200 and 400 mg/kg) 5 h post-carrageeenan. Exudate volume was significantly reduced to 39.8 and 44.8% by 200 and 400 mg/kg WDP, respectively. WDP reduced Leucocytes counts (23.3 and 57.1%, respectively) and neutrophil counts (28.1 and 60.0%, as well as reduced nitrites, malondialdehyde levels and increased glutathione concentrations in the air pouch.

CONCLUSIONS

These results suggest that aqueous extract of blend of seeds and leaves of P. nitida possesses antinociceptive and anti-inflammatory properties.

Critical Evaluation of Animal Models of Gastrointestinal Disorders

Preclinical research remains an important tool for discovery and validation of novel therapeutics for gastrointestinal disorders. While in vitro assays can be used to verify receptor-ligand interactions and test for structural activity of new compounds, only whole-animal studies can demonstrate drug efficacy within the gastrointestinal system. Most major gastrointestinal disorders have been modeled in animals; however the translational relevance of each model is not equal. The purpose of this chapter is to provide a critical evaluation of common animal models that are being used to develop pharmaceuticals for gastrointestinal disorders. For brevity, the models are presented for upper gastrointestinal disorders involving the esophagus, stomach, and small intestine and lower gastrointestinal disorders that focus on the colon. Particular emphasis is used to explain the face and construct validity of each model, and the limitations of each model, including data interpretation, are highlighted. This chapter does not evaluate models that rely on surgical or other non-pharmacological interventions for treatment.

Endogenous Opiates and Behavior: 2015

This paper is the thirty-eighth consecutive installment of the annual review of research concerning the endogenous opioid system. It summarizes papers published during 2015 that studied the behavioral effects of molecular, pharmacological and genetic manipulation of opioid peptides, opioid receptors, opioid agonists and opioid antagonists. The particular topics that continue to be covered include the molecular-biochemical effects and neurochemical localization studies of endogenous opioids and their receptors related to behavior, and the roles of these opioid peptides and receptors in pain and analgesia, stress and social status, tolerance and dependence, learning and memory, eating and drinking, drug abuse and alcohol, sexual activity and hormones, pregnancy, development and endocrinology, mental illness and mood, seizures and neurologic disorders, electrical-related activity and neurophysiology, general activity and locomotion, gastrointestinal, renal and hepatic functions, cardiovascular responses, respiration and thermoregulation, and immunological responses.