Synthetic modification of hydroxychavicol by Mannich reaction and alkyne-azide cycloaddition derivatives depicting cytotoxic potential

Rational design and synthesis of novel phenyltriazole derivatives targeting MRSA cell wall biosynthesis

Antimicrobial resistance in methicillin-resistant Staphylococcus aureus (MRSA) is a major global health challenge. This study reports the design and synthesis of novel phenyltriazole derivatives as potential anti-MRSA agents. The new scaffold replaces the thiazole core with a 1,2,3-triazole ring, enhancing antimicrobial efficacy and physicochemical properties. A series of derivatives were synthesized and evaluated, with four compounds (20, 23, 29 and 30) showing significant activity against MRSA (MIC ≤ 4 μg mL-1). Compound 29 emerged as the most promising candidate, showing rapid bactericidal activity and superior performance over vancomycin in time-kill assays. It exhibited selective toxicity against bacterial cells, minimal cytotoxicity in human cell lines and low hemolytic activity. Mechanistic studies showed that compound 29 targets the bacterial cell wall by binding to penicillin-binding protein 2a (PBP2a), disrupting cell wall integrity. Additionally, it showed strong anti-biofilm activity and reduced MRSA biofilms by up to 40%. Preliminary pharmacokinetic profiles suggested a favorable profile, including a prolonged plasma half-life and good oral bioavailability. These results suggest that compound 29 is a promising lead for further development in the fight against MRSA.

Anticancer activity of Mannich bases: a review of recent literature

This report summarizes the latest published data on the antiproliferative action and cytotoxic activity of Mannich bases, a structurally heterogeneous category of chemical entities that includes compounds which are synthesized via the grafting of an aminomethyl function onto diverse substrates by means of the Mannich reaction. The present overview of the topic is an update to the information assembled in a previously published review that covered the literature up to 2014.

Aryl Azides as Forgotten Electrophiles in the Van Leusen Reaction: A Multicomponent Transformation Affording 4-Tosyl-1-arylimidazoles

Considering aryl azides as electrophilic partners for the TosMIC mediated Van Leusen reaction, a novel multicomponent synthesis of 4-tosyl-1-arylimidazoles is reported. In this transformation, two molecules of TosMIC participate in the reaction mechanism in two different ways, with the second molecule undergoing a novel type of fragmentation resulting in the incorporation of a C-H into the final product.

Hydroxychavicol, a key ingredient of Piper betle induces bacterial cell death by DNA damage and inhibition of cell division

Antibiotic resistance is a global problem and there is an urgent need to augment the arsenal against pathogenic bacteria. The emergence of different drug resistant bacteria is threatening human lives to be pushed towards the pre-antibiotic era. Botanical sources remain a vital source of diverse organic molecules that possess antibacterial property as well as augment existing antibacterial molecules. Piper betle, a climber, is widely used in south and south-east Asia whose leaves and nuts are consumed regularly. Hydroxychavicol (HC) isolated from Piper betle has been reported to possess antibacterial activity. It is currently not clear how the antibacterial activity of HC is manifested. In this investigation we show HC generates superoxide in E. coli cells. Antioxidants protected E. coli against HC induced cell death while gshA mutant was more sensitive to HC than wild type. DNA damage repair deficient mutants are hypersensitive to HC and HC induces the expression of DNA damage repair genes that repair oxidative DNA damage. HC treated E. coli cells are inhibited from growth and undergo DNA condensation. In vitro HC binds to DNA and cleaves it in presence of copper. Our data strongly indicates HC mediates bacterial cell death by ROS generation and DNA damage. Damage to iron sulfur proteins in the cells contribute to amplification of oxidative stress initiated by HC. Further HC is active against a number of Gram negative bacteria isolated from patients with a wide range of clinical symptoms and varied antibiotic resistance profiles.

Alkyne-azide cycloaddition analogues of dehydrozingerone as potential anti-prostate cancer inhibitors via the PI3K/Akt/NF-kB pathway

Herein, we report the isolation and synthetic modification of dehydrozingerone (DHZ, 1), a secondary metabolite present in the rhizome of Zingiber officinale. We synthesized O-propargylated dehydrozingerone, which was subsequently coupled by alkyne-azide cycloaddition (3-20) using click chemistry. The compounds (1-20) were evaluated for their in vitro cytotoxic activity in a panel of three cancer cell lines. Among all the DHZ derivatives, 3, 6, 7, 8, 9 and 15 displayed potent cytotoxic potential with an IC50 value ranging from 1.8-3.0 μM in MCF-7, PC-3 and HCT-116 cell lines. Furthermore, compound 7 has proven to be the most potent cytotoxic compound in all the three distinct cancer cell lines and also demonstrated significant anti-invasive potential in prostate cancer. The mechanistic study of compound 7 showed that it not only suppressed the AKT/mTOR signalling which regulates nuclear transcription factor-NF-kB but also augmented the expression of anti-invasive markers E-cadherin and TIMP. Compound 7 significantly decreased the expression of pro-invasive markers vimentin, MMP-2 and MMP-9, respectively. This study underscores an efficient synthetic approach employed to evaluate the structure-activity relationship of dehydrozingerone (1) in search of potential new anticancer agents.