Synthesis and molecular docking of new hydrazones derived from ethyl isonipecotate and their biological activities

Purpose: To investigate the antibacterial and α-glucosidase inhibitory activities of hydrazone derivatives (8a-h) of ethyl isonipecotate.Methods: The reaction of ethyl isonipecotate (2) with 3,5-dichloro-2-hydroxybenzenesulfonyl chloride (1) in an aqueous basic medium yielded ethyl 1-[(3,5-dichloro-2-hydroxyphenyl)sulfonyl]piperidin-4- carboxylate (3). Compound 3 was subsequently converted to ethyl 1-[(3,5-dichloro-2-ethoxyphenyl) sulfonyl]piperidin-4-carboxylate (5) via O-alkylation. Compound 5 on reaction with hydrated hydrazine yielded 1-[(3,5-dichloro-2-ethoxyphenyl)sulfonyl]piperidin-4-carbohyrazide (6) in MeOH. Target compounds 8a-h were synthesized by stirring 6 with different aromatic aldehydes (7a-h) in MeOH. All the synthesized compounds were structurally elucidated by proton nuclear magnetic resonance (1H-NMR), electron impact mass spectrometry (EI-MS) and infrared (IR) spectroscopy. For antibacterial activity, solutions of the synthesized compounds were mixed with bacterial strains, and the change in absorbance before and after incubation was determined. For enzyme inhibitory activity, change in the absorbance of mixtures of synthesized compounds and enzyme before and after incubation with substrate was determined.Results: The target compounds were synthesized in appreciable yields and well characterized by spectral data analysis. Salmonella typhi was inhibited by 8e (MIC 8.00 ± 0.54 μM), Escherichia coli by 8f (8.21 ± 0.83 μM), Bacillus subtilis by 8c (8.56 ± 0.63 μM) and Staphylococcus aureus by 8c (8.86 ± 0.29 μM). Two compounds, 8e and 8d, were very effective inhibitors of α-glucosidase with IC50 values of 40.62 ± 0.07 and 48.64 ± 0.08 μM, respectively.Conclusion: Low IC50  values of the synthesized compounds against α-glucosidase demonstrates their potential in type-2 diabetes treatment. Furthermore, these compounds exhibit substantial antibacterial activity against the bacterial strains tested.Keywords: Antibacterial activity, α-Glucosidase inhibition, Ethyl isonipecotate, Hydrazo

Biological screening and docking studies of unique hybrids synthesized by conventional versus microwave assisted techniques

Purpose: To carry out the synthesis of various hybrids of 1,2,4-triazole in search of potential therapeutic enzyme inhibitory agents, and carry out docking and bovine serum albumin (BSA) binding studies on docking and bovine serum albumin (BSA) binding studies on the hybrids. Methods: The target compounds were synthesized by following a multistep protocol. Compound 1 was synthesized from 4-methoxybenzenesulfonyl chloride (a) and ethyl isonipecotate (b). Compound 1 was refluxed with hydrazine to synthesize compound 2, which was converted to compound 3 through two consecutive steps. Compound 4 and different amines (5a-5i), were utilized to synthesize an array of electrophiles (6a-6i). A series of 1,2,4-triazole hybrids (7a-7i) were synthesized at room temperature by stirring together 3 and 6a-6i. The final structures of 7a-7i were elucidated through 1H-NMR, 13C-NMR and EI-MS spectroscopy. The BSA binding studies were performed by fluorometric titration. Furthermore, antioxidant and enzyme inhibition activities were determined colorimetrically. Results: Compound 7d was the most active antioxidant agent, compared to butylated hydroxyanisole (BHA), while compounds 7d, 7e, 7f, 7g and 7i proved to be potent urease inhibitors with half-maximal inhibitory concentration (IC50) values of 19.5 ± 0.12, 21.1 ± 0.68, 18.2 ± 0.78, 19.9 ± 0.77 and 17.9 ± 0.10 µM, respectively, compared to thiourea with an IC50 of 24.3 ± 0.24 µM. Compounds 7a, 7b, 7d, and 7e exhibited high butyrylcholinesterase inhibition potential, compared to eserine. Conclusion: The synthesized compounds require studies further as potential therapeutic enzyme inhibitory agents in view of their urease inhibition as well as antioxidant activity

Application of the Milan System for Reporting Submandibular Gland Cytopathology: An international, multi-institutional study.

The Milan System for Reporting Salivary Gland Cytopathology (MSRSGC) is a 6-tier diagnostic category system with associated risks of malignancy (ROMs) and management recommendations. Submandibular gland fine-needle aspiration (FNA) is uncommon with a higher frequency of inflammatory lesions and a higher relative proportion of malignancy, and this may affect the ROM and subsequent management. This study evaluated the application of the MSRSGC and the ROM for each diagnostic category for 734 submandibular gland FNAs. Submandibular gland FNA cytology specimens from 15 international institutions (2013-2017) were retrospectively assigned to an MSRSGC diagnostic category as follows: nondiagnostic, nonneoplastic, atypia of undetermined significance (AUS), benign neoplasm, salivary gland neoplasm of uncertain malignant potential (SUMP), suspicious for malignancy (SM), or malignant. A correlation with the available histopathologic follow-up was performed, and the ROM was calculated for each MSRSGC diagnostic category. The case cohort of 734 aspirates was reclassified according to the MSRSGC as follows: nondiagnostic, 21.4% (0%-50%); nonneoplastic, 24.2% (9.1%-53.6%); AUS, 6.7% (0%-14.3%); benign neoplasm, 18.3% (0%-52.5%); SUMP, 12% (0%-37.7%); SM, 3.5% (0%-12.5%); and malignant, 13.9% (2%-31.3%). The histopathologic follow-up was available for 333 cases (45.4%). The ROMs were as follows: nondiagnostic, 10.6%; nonneoplastic, 7.5%; AUS, 27.6%; benign neoplasm, 3.2%; SUMP, 41.9%; SM, 82.3%; and malignant, 93.6%. This multi-institutional study shows that the ROM of each MSRSGC category for submandibular gland FNA is similar to that reported for parotid gland FNA, although the reported rates for the different MSRSGC categories were variable across institutions. Thus, the MSRSGC can be reliably applied to submandibular gland FNA