Mini Reviews in Medicinal Chemistry - Volume 18, Issue 17, 2018

Berberine, a quaternary ammonium protoberberine alkaloid with an isoquinoline scaffold isolated from medicinal herbs, exhibits a wide spectrum of pharmacological activities. Berberine has been used in traditional Chinese medicine and Ayurvedic medicine. However, it has poor bioavailability, which seriously limits its application and development. The chemical transformation of natural products is an effective method to improve pharmacological activities. Researches have been carried out on the modification of berberine to obtain better pharmacological properties. In this paper, the structural modifications of berberine for different biological activities and its underlying mechanisms are reviewed.

The incidence of Tuberculosis (TB) is baffling in developing countries due to the increase in multidrug-resistant and extensively drug-resistant TB. Therefore, drugs acting through different mechanisms are in dire need to counter the resistant strains. Various chemical scaffolds are being investigated against tuberculosis, among them the molecules containing phenothiazine nucleus are found to be more effective against both susceptible and resistant strains of M. tuberculosis. In addition, the efficacy of first-line drugs has been found to be enhanced on supplementary treatment with phenothiazines. The present review provides an overview of the phenothiazine based molecules which were investigated during the last ten years for their anti-tubercular activity.

Nitrogen and sulphur based heterocyclic molecules have gained significant attention owing to their broad spectrum pharmacological profiles. Thiazine is one of such promising scaffolds which has been widely utilized in the synthesis of compounds that possess interesting biological profile including anti-proliferative, anti-bacterial, antipsychotic, analgesic, anti-inflammatory, antifungal and antiviral activities. The current review focuses on the chemistry of thiazine and its derivatives along with potential pharmacological activities reported for these in scientific literature. Multifaceted pharmacological profile of thiazine derivatives provides new aspects for the design of superior medicinally active agents.

Repetitive transcranial magnetic stimulation (rTMS) is a well known non-invasive brain stimulation procedure which is capable of inducing the expression of the hippocampal BDNF that has been already shown to exert significant neuroprotective and pro-cognitive effects in AD. However, it is nearly impossible directly to evaluate the BDNF expression in humans after rTMS application. Here we summarized the underlying mechanisms of the neuroprotective and procognitive effect of BDNF that can be induced through a region-specific rTMS approach. Additionally, we have also evaluated the role of Magnetic Resonance Spectroscopy in monitoring the BDNF response after rTMS application in Alzheimer's Disease. We have provided strong evidence that rTMS exerts significant neuroprotective and pro-cognitive effects through the expression of hippocampal BDNF. Furthermore, Magnetic Resonance Spectroscopy might play a critical role in monitoring the BDNF response after rTMS application in AD patients. Such a sophisticated approach might be able to enlighten us on the time-dependent cognitive and neuroprotective correlates of the rtMS application in AD patients.

Background: Twenty one amide compounds possessing phenoxy/benzyloxy/pyridinyl groups have been synthesized by benzoylation of respective amines in presence of base with moderate to encouraging yields. Upon confirmation of structure, compounds were subjected for p38 kinase inhibitory, anti-inflammatory, antimicrobial and antitubercular activities. Method: Anti-inflammatory activity was determined using carrageenan induced rat paw edema model while p38 kinase inhibitory activity was studied using ELISA method and serial dilution method was employed to determine MICs. Two compounds 4g and 4n showed over 30% p38 kinase inhibitory activity at 10 μM and best anti-inflammatory activity was found for compounds 4g, 4i, 4n and 4o which exhibited to reduce paw edema over 70%. Compound 4b was observed to be the most potent against gram +ve organisms with MIC value of 1.6 μG/mL and compound 4u displayed potent antibacterial activity against gram negative organisms. Conclusion: Most encouraging antitubercular activity was noticed for compounds 4u, 4r and 4k with 6.25, 12.5 and 12.5 μG/mL Further, in order to know the binding site interactions, a docking simulations of compounds was performed. These preliminary results will certainly show fruitful directions to improve the activities of compounds.

Background: 3-Methyleneisoindolin-1-one derivatives containing a pyridin-2-ylmethyl substituent on their ring nitrogen were designed as potential bioactive agents. A one-pot synthesis of these compounds was achieved via sequential C-C coupling, followed by C-Si bond cleavage and subsequent tandem C-C/C-N bond forming reaction under ultrasound irradiation. Method: The methodology involved coupling of (trimethylsilyl)acetylene with iodoarenes in the presence of 10% Pd/C-CuI-PPh3-Et3N in MeOH followed by treating the reaction mixture with K2CO3 in aqueous MeOH, and finally coupling with 2-iodo-N-(pyridin-2-ylmethyl)benzamide. The in vitro evaluation of these compounds was performed to identify some initial hit molecules one of which showed dose dependent inhibition of PDE4B.