7-Chloro-5-(furan-3-yl)-3-methyl-4H-benzo[e][1,2,4]thiadiazine 1,1-Dioxide as Positive Allosteric Modulator of α-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid (AMPA) Receptor. The End of the Unsaturated-Inactive Paradigm?

Abstract

5-Arylbenzothiadiazine type compounds acting as positive allosteric modulators of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid receptor (AMPA-PAMs) have received particular attention in the past decade for their nootropic activity and lack of the excitotoxic side effects of direct agonists. Recently, our research group has published the synthesis and biological activity of 7-chloro-5-(3-furanyl)-3-methyl-3,4-dihydro-2H-1,2,4-benzothiadiazine 1,1-dioxide (1), one of the most active benzothiadiazine-derived AMPA-PAMs in vitro to date. However, 1 exists as two stereolabile enantiomers, which rapidly racemize in physiological conditions, and only one isomer is responsible for the pharmacological activity. In the present work, experiments carried out with rat liver microsomes show that 1 is converted by hepatic cytochrome P450 to the corresponding unsaturated derivative 2 and to the corresponding pharmacologically inactive benzenesulfonamide 3. Surprisingly, patch-clamp experiments reveal that 2 displays an activity comparable to that of the parent compound. Molecular modeling studies were performed to rationalize these results. Furthermore, mice cerebral microdialysis studies suggest that 2 is able to cross the blood-brain barrier and increases acetylcholine and serotonin levels in the hippocampus. The experimental data disclose that the achiral hepatic metabolite 2 possesses the same pharmacological activity of its parent compound 1 but with an enhanced chemical and stereochemical stability, as well as an improved pharmacokinetic profile compared with 1.

A Metabolomic Approach Applied to a Liquid Chromatography Coupled to High‐Resolution Tandem Mass Spectrometry Method (HPLC‐ESI‐HRMS/MS): Towards the Comprehensive Evaluation of the Chemical Composition of Cannabis Medicinal Extracts

“…In this work there was no handling of new cannabis based material since all the samples employed were the same that have been previously analysed and reported in our recent paper (Citti et al, ).…”

“…The extraction procedure followed is the one recently proposed by Citti et al . (), which involves the use of a condenser to minimise the loss of any volatile substance.…”

“…Then, 5 μL were injected directly into the HPLC system and analysed in five replicates. For the quantitative determination of CBDA, CBD, CBN, THC and THCA, 10 μL of IS was added at a final concentration of 500 μg/mL in line with the recently published LC–MS and LC‐UV method (Citti et al, ).…”

“…The scientific literature reveals a serious gap concerning the determination of the concentration of the two main cannabinoids THC and CBD in CMEs. The first research work regarding the evaluation of the main cannabinoids concentration and stability in oil and ethyl alcohol CMEs by LC–MS (and LC‐UV) was developed and validated by our group (Citti et al, ). More recently, Pacifici et al .…”

“…A tentative identification of a few interesting compounds was hypothesised on the basis of accurate mass, isotopic pattern and high‐resolution fragmentation spectrum match with METLIN (Zhu et al, ) online database. Moreover, the main cannabinoids (CBDA, THCA, CBD, THC and CBN) concentration was evaluated in each extract using the recently validated LC–MS/MS method (Citti et al, ).…”