Antioxidant and antimicrobial studies of novel N′-(substituted-2-chloroquinolin-3-yl)methylidene-4-hydroxy-2H-1,2-benzothiazine-3-carbohydrazides 1,1-dioxides

Exploring of novel 4-hydroxy-2H-benzo[e][1,2]thiazine-3-carbohydrazide 1,1-dioxide derivative as a dual inhibitor of α-glucosidase and α-amylase: Molecular docking, biochemical, enzyme kinetic and in-vivo mouse model study

Diabetes mellitus (DM) is a metabolic disorder that leads to hyperglycemia due to improper insulin secretion. The study aims to investigate the anti-diabetic potential of benzothiazine derivatives. Molecular docking and Molecular Dynamics simulation study revealed that Compound S6 (4-hydroxy-2H-benzo[e][1,2]thiazine-3-carbohydrazide 1,1-dioxide) and S7 (4-Hydroxy-2-methyl-2H-1,2-benzothiazine-3-carbohydrazide 1,1-dioxide) had less conformational changes during MD simulation analysis at 100 ns. Compound S6 and S7 showed potent activity with IC50 values of 5.93 μM, 6.91 μM and 75.17, 29.10 μM for α-glucosidase and α-amylase respectively and competitive type of inhibition was observed during enzyme kinetic study with a low value of Ki and Ki' for α-glucosidase and α-amylase, respectively. S6 has the lowest Ki (0.0736) and Ki' (-0.0982) for α-glucosidase. Furthermore, in vivo studies were carried out to distinguish the effects of the drug on the body. Histology analysis on mice model showed that compound S6 has a low necrosis rate in the liver, kidney, and pancreas compared to S7. Biochemical results of S6 revealed lower sugar level (112 mg/dL), increase insulin secretion (23, 25 μM/L), and low level of cholesterol (80, 85 mg/dL) and creatinine (1.6, 1.4 mg/dL). The results conclude that compound S6 is a new anti-diabetic agent that minimizes hyperglycemia complications.

Synthesis and biological evaluation as well as in silico studies of arylpiperazine-1,2-benzothiazine derivatives as novel anti-inflammatory agents

Novel arylpiperazine-1,2-benzothiazine derivatives have been designed and synthesized as potential anti-inflammatory agents. Their structure and properties have been studied using spectroscopic techniques (¹H NMR, ¹³C NMR, FT-IR), MS, elemental analyses, and single-crystal X-ray diffraction (SCXRD, for compound 7b). This study aimed to evaluate the inhibitory activity of new derivatives against both cyclooxygenase isoforms COX-1 and COX-2 due to the similarity of new compounds to oxicams drugs from the NSAIDs group. All new compounds were divided into two series - A and B - with a different linker between thiazine and piperazines nitrogens. Series A included the three-carbon aliphatic linker and series B - two-carbon with a carbonyl group. According to in vitro and molecular docking studies all new compounds exhibited cyclooxygenase inhibitory activity. The series of A compounds included COX-1 inhibitors only. In contrast, the B series showed inhibition of both COX-1 and COX-2, which suggested the importance of the acetoxy linker for COX-2 inhibition. Moreover, the most selective compound 7b, towards COX-2, was non-toxic for the normal human cell line (in concentration of 10 µM) comparable to reference drug meloxicam. Additionally, investigation of influence on model membranes confirmed the ability of the compound 7b to penetrate lipid bilayers which seemed to be important to the influence with membrane protein-cyclooxygenase.

Evaluation of 1,2-Benzothiazine 1,1-dioxide Derivatives In Vitro Activity towards Clinical-Relevant Microorganisms and Fibroblasts

The global concern related with growing number of bacterial pathogens, resistant to numerous antibiotics, prone scientific environment to search for new antimicrobials. Antiseptics appear to be suitable candidates as adjunctive agents to antibiotics or alternative local treatment option aiming to prevent and treat infections. 1,2-benzothiazines are considered one the most promising of them. In this research twenty 1,2-benzothiazine 1,1-dioxide derivatives were scrutinized with regard to their biological activity. Three of them are new. For evaluation of compounds' activity against microbial pathogens, disk diffusion method and serial microdilution method was applied. To establish the cytotoxicity profile of tested 1,2-benzothiazines 1,1-dioxides derivatives, the cytotoxicity assay using fibroblasts L292 was performed. Antimicrobial activity of all tested compounds against Gram-positive Staphylococcus aureus and Enterococcus faecalis strains was higher than antimicrobial activity of DMSO solvent, which possesses antimicrobial activity itself. Gram-negative P. aeruginosa, E. coli and K. pneumoniae have shown susceptibility only to compounds 3e, 7i and 7l. None of tested compounds was effective against C. albicans. Compound 6g has demonstrated the strongest antimicrobial potency (MIC = 0.00975 mg/mL) among compounds of series 6. Compounds of series 7, namely 7d, 7f, 7g had the lowest minimum inhibitory concentration (MIC). Compound 7f displayed also the lowest cytotoxic effect against fibroblast cell line among series 7 compounds. All tested derivatives displayed lower MIC against Gram-positive bacteria than commercially applied antiseptic, povidone iodine, which MIC value range for tested Gram-positive bacteria was 1.56-6.25 mg/mL.

Molecular docking and antiviral activity of N-substituted benzyl/phenyl-2-(3,4-dimethyl-5,5-dioxidopyrazolo[4,3-c][1,2]benzothiazin-2(4H)-yl)acetamides

Two series of fifteen N-substituted benzyl/phenyl-2-(3,4-dimethyl-5,5-dioxidopyrazolo[4,3-c][1,2]benzothiazin-2(4H)-yl)acetamides were screened for anti-HIV-1 activity and cytotoxicity. The compounds 6a, 6d, 6e, 6g and 6i from the series 6a-i of benzylamides and 7a, 7b, 7c, 7d and 7e from the series 7a-f of anilides were identified as effective anti-HIV-1 agents with EC50 values <20μM. Among these compounds that displayed anti-HIV-1 activity, 6a, 6e, 6g and 6i showed no toxicity in human PBM, CEM and Vero cells, with the exception of 6a which displayed toxicity in Vero cells. Molecular docking of these compounds provided insight into the molecular mechanism and it was found that 6e, 6g and 6i bound deeply in the NNRTI binding pocket of the HIV-1 reverse transcriptase, using RT-bound nevirapine X-ray data and molecular docking for validation, showing the potential of these new structures as inhibitors of this viral enzyme.

Synthesis and anti-HIV-1 screening of novel N'-(1-(aryl)ethylidene)-2-(5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]thiazin-4(1H)-yl)acetohydrazides

A novel series of N'-(1-(aryl)ethylidene)-2-(5,5-dioxido-3-phenylbenzo[e]pyrazolo[4,3-c][1,2]thiazin-4(1H)-yl)acetohydrazides was synthesized. The synthesis was carried out by thermal method as well as ultrasonic bath to reduce reaction time and to enhance product yields. The synthesized compounds were characterized by spectroscopic techniques like NMR, infrared and EIMS. The structure of compound 5w was elucidated by X-ray crystallography. The titled compounds were evaluated for anti-human immunodeficiency virus type 1 (anti-HIV-1) and cytotoxic activities. Biological studies indicated that amongst these compounds, 5a, b, j, h and i showed the activity with median effective concentration (EC50) values less than 20 μM. Compound 5i exhibited the most potent anti-HIV-1 activity (EC50 = 3.2 μM) while 5h showed anti-HIV-1 activity (EC50 = 3.8 μM) with no toxicity at all in primary human lymphocytes, CEM and VERO cells.

Design, synthesis, antinociceptive and anti-inflammatory activities of novel piroxicam analogues

In this paper we report the design, synthesis, antinociceptive and anti-inflammatory activities of a series of benzothiazine N-acylhydrazones 14a–h, planned by structural modification of piroxicam (1), a non steroidal anti-inflammatory drug. Among the synthesized analogues, compounds 14f (LASSBio-1637) and 14g (LASSBio-1639) were identified as novel antinociceptive and anti-inflammatory prototypes, active by oral administration, acting by a mechanism of action that seems to be different from that of piroxicam, since they were inactive as an inhibitor of cyclooxygenase (COX-1 and COX-2) at concentrations of 10 μM.