ABSTRACT
The widespread incidence of antimicrobial resistance necessitates the discovery of new classes of antimicrobials as well as adjuvant molecules that can restore the action of ineffective antibiotics. Herein, we report the synthesis of a new class of indole-3-acetamido-polyamine conjugates that were evaluated for antimicrobial activities against a panel of bacteria and two fungi, and for the ability to enhance the action of doxycycline against Pseudomonas aeruginosa and erythromycin against Escherichia coli. Compounds 14b, 15b, 17c, 18a, 18b, 18d, 19b, 19e, 20c and 20d exhibited strong growth inhibition of methicillin-resistant Staphylococcus aureus (MRSA) and Cryptococcus neoformans, with minimum inhibitory concentrations (MIC) typically less than 0.2 µM. Four analogues, including a 5-bromo 15c and three 5-methoxyls 16d-f, also exhibited intrinsic activity towards E. coli. Antibiotic kill curve analysis of 15c identified it to be a bactericide. While only one derivative was found to (weakly) enhance the action of erythromycin against E. coli, three examples, including 15c, were found to be strong enhancers of the antibiotic action of doxycycline against P. aeruginosa. Collectively, these results highlight the promising potential of α,ω-disubstituted indole-3-acetamido polyamine conjugates as antimicrobials and antibiotic adjuvants.
Subject(s)
Anti-Infective Agents , Fatty Acids, Omega-3 , Methicillin-Resistant Staphylococcus aureus , Anti-Bacterial Agents/pharmacology , Doxycycline , Escherichia coli , Adjuvants, Immunologic , Adjuvants, Pharmaceutic , Erythromycin/pharmacology , Indoles/pharmacology , Polyamines/pharmacology , Pseudomonas aeruginosaABSTRACT
Breast cancer is known as the most devastating cancer in the global female community and is considered as one of the severe health care burdens in both developed and developing countries. In many cases, breast cancer has shown resistance to chemotherapy, radiotherapy and hormonal therapy. Keeping in view these limitations, there is an urgent need to develop safe, readily available and effective breast anticancer treatments. Therefore, the scientists are keen in the extraction of plant-based phytochemicals (organosulfur compounds, betalains, capsaicinoids, terpenes, terpenoids, polyphenols, and flavonoids) and using them as breast anticancer agents. Results of numerous epidemiological investigations have revealed the promising role of phytochemicals in the prevention and treatment of breast cancer. The diverse classes of plant bioactive metabolites regulate different metabolic and molecular processes, which can delay the proliferation of cancers. These phytochemicals possess chemo-preventive properties as they down-regulate the expression of estrogen receptor-α, inhibit the proliferation of cancer cells, and cause cell cycle arrest by inducing apoptotic conditions in tumor cells. This review article discusses the potent role of various plant-based phytochemicals as potential therapeutic agents in the treatment or prevention of breast cancer along with the proposed mechanisms of action.