Synthesis, biological evaluation and molecular docking studies of 8-(hetero)aryl caffeine derivatives

Abstract

A series of 8-(hetero)aryl caffeine was synthesized by the CH bond activation reaction using Pd-NHCs complexes as a catalyst. 8-(hetero)aryl caffeine derivatives were screened for their antioxidant, antimicrobial, and enzyme inhibitory activities and in-silico studies. The 4a, 4b, 4e, 4f, 4 g, 4i, and 4n showed significant total antioxidant capacity (TAC) of 64.03, 50.87, 70.02, 98.14, 71.81, 45.48, and 44.28 µg AAE/mg, respectively. The 4a, 4b, 4d, 4e, 6 h, 4i, 4j, 4k, and 4l were found active against Staphylococcus aureus at a minimum inhibitory concentration of 25, 12.5, 12.5, 12.5, 12.5, 6.25, 6.25, 6.25, and 6.25 µg/ml, respectively. Some derivatives displayed activity against Escherichia coli, Bacillus subtilus, Klebsiella pneumonae, and Pseudomonas aeruginosa.A good activity was exhibited against Alternaria solani among five fungal strains. All the compounds (4a–4n) showed excellent protein kinase inhibitory activity except 4e, 4 g, and 4n. Additionally, 8-(hetero)aryl caffeine derivatives showed α-amylase inhibition potential (IC50 = 1.49 ± 0.317 to 7.44 ± 0.156 μg/ml) compared to standard acarbose (IC50 = 4.34 ± 0.333 μg/ml). The 4b, 4d, 4j, 4 m, and 4n compounds displayed good α-glucosidase inhibitory potential. Molecular modeling was done for protein kinase, α-amylase, and α-glucosidase. The results of these activities proved the caffeine derivatives to be bioactive.