Synthesis and bioactivity evaluation of eugenol hybrids obtained by Mannich and 1,3 dipolar cycloaddition reactions

Current scenario of chalcone hybrids with antibreast cancer therapeutic applications

Breast cancer, an epithelial malignant tumor that occurs in the terminal ducts of the breast, is the most common female malignancy. Currently, approximately 70%-80% of breast cancer with early-stage, nonmetastatic disorder is curable, but the emergency of drug resistance often leads to treatment failure. Moreover, advanced breast cancer with distant organ metastases is incurable with the available therapeutics, creating an urgent demand to explore novel antibreast cancer agents. Chalcones, the precursors for flavonoids and isoflavonoids, exhibit promising activity against various breast cancer hallmarks, inclusive of proliferation, angiogenesis, invasion, metastasis, inflammation, stemness, and regulation of cancer epigenetics, representing useful scaffolds for the discovery of novel antibreast cancer chemotherapeutic candidates. In particular, chalcone hybrids could act on two or more different biological targets simultaneously with more efficacy, lower toxicity, and less susceptibility to resistance. Accordingly, there is a huge scope for application of chalcone hybrids to tackle the present difficulties in breast cancer therapy. This review outlines the chalcone hybrids with antibreast cancer potential developed from 2018. The structure-activity relationships as well as mechanisms of action are also discussed to shed light on the development of more effective and multitargeted chalcone candidates.

Combining eugenol and dihydroeugenol with a piperazine moiety to create new antimicrobial agents that are effective against resistant species

Historically, the piperazine moiety has been demonstrated to possess pharmacophoric properties, and has subsequently been incorporated in many drugs that have antitumor, antimalarial, antiviral, antibacterial and antifungal properties. Derivatives of eugenol and dihydroeugenol have also been reported as being bioactive compounds. This study reports the synthesis of a range of eugenol/dihydroeugenol - piperazine derivatives which have been tested as antimicrobial compounds against Gram positive, Gram negative and rapid-growing mycobacteria (RGM). The rationale employed in the design of the structural pattern of these new derivatives, provides useful insights into the structure-activity relationships (SAR) of the series. Antimicrobial activity tests were extremely encouraging, with the majority of the synthesised compounds being more active than eugenol and dihydroeugenol starting materials. The antimicrobial potential was most notable against the Gram-negative species K. pneumoniae and P. aeruginosa, but there was also significant performance against the Gram-positive strains S. epidermidis and S. aureus and the Rapidly Growing Mycobacteria (RGM) strains tested. Tests using the synthesised compounds against multidrug-resistance clinical (MDR) isolates also showed high activity. The biofilm inhibition tests using M. fortuitum showed that all evaluated derivatives were able to inhibit biofilm formation even at low concentrations. In terms of structural-activity relationships; the results generated by this study demonstrate that the compounds with bulky substituents on the piperazine subunit were much more active than those with less bulky groups, or no groups. Importantly, the derivatives with a sulfonamide side chain were the most potent compounds. A further observation was that those compounds with a para-substituted benzenesulfonamide ring stand out, regardless of whether this substituent is a donor or an electron-withdrawing group.

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.