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Coumarins are the phytochemicals, which belong to the family of benzopyrone, that display interesting pharmacological properties. Several natural, synthetic and semisynthetic coumarin derivatives have been discovered in decades for their applicability as lead structures as drugs. Coumarin based conjugates have been described as potential AChE, BuChE, MAO and β-amyloid inhibitors. Therefore, the objective of this review is to focus on the construction of these pharmacologically important coumarin analogues with anti-Alzheimer’s activities, highlight their docking studies and structure–activity relationships based on their substitution pattern with respect to the selected positions on the chromen ring by emphasising on the research reports conducted in between year 1968 to 2017.

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In the present study, chemical composition and antioxidant activity of essential oil from the aerial parts of Alternanthera sessilis red has been investigated. The chemical composition of essential oil of A. sessilis red was determined by GC-MS analysis. Determination of antioxidant nature of A. sessilis red was carried out by 1,1diphenyl-2-picrylhydrazyl (DPPH) radical scavenging method using butylated hydroxytoulene (BHT)as the positive control. The major components of essential oil of leaves, as analyzed by the GC-MS were found to be 1,1,1,5,5,5-hexamethyl-3,3-bis[trimethylsilyl)oxy]trisiloxane (15.43%), S,S-dioxide trans-2-methyl-4-Npentylthiane (11.27%), didodecylphthalate (10.62%) and tetrahydro-2,5-dimethoxy furan (10.01%).However, the major components of essential oil of flower were 1,1,1,5,5,5-hexamethyl-3,3bis[trimethylsilyl)oxy]trisiloxane (17.76%), trans-4-ethyl-5-octyl-2,2-bis(trifluromethyl)-1,3-dioxolane (11.12%) and tetrahydro-2,5-dimethoxy furan ( 9.10%).

A series of novel 4-thiazolidinone inhibitors SKYa–SKYg, containing coumarin as a core structure were synthesized via facile and efficient method. The structures of the synthesized compounds were established by extensive spectroscopic studies (FT IR, 1D NMR, 2D NMR, LC–MS) and elemental analysis. All the synthesized hybrids were further evaluated for their potential as anti-tubercular agents against Mycobacterium tuberculosis H37Rv ATCC 25618, and anti-bacterial agents against Escherichia coli, Enterobacter aerogenes, Salmonella typhi, Streptococcus pneumoniae and Staphylococcus aureus. Interestingly, the hybrids displayed potent bioactivity. However, compounds SKYc, SKYd, and SKYe appeared to be more effective against the tested bacterial strains, among which compound SKYb showed the highest inhibition against all the bacterial strains ranging from 41 to 165 μg/mL, as compared to the standards, streptomycin, kanamycin and vancomycin. Moreover, derivative SKYa was found to be the strongest against M. tuberculosis (83 μg/mL). Additionally, the anti-dengue potential of the coumarin hybrids as two-component NS2B/NS3 DENV flavivirus serine protease inhibitors was calculated using computational molecular docking approach, with reference to the standards 4-hydroxypanduratin, panduratin and ethyl 3-(4-(hydroxymethyl)-2-methoxy-5-nitrophenoxy)propanoate with DS of − 3.379, − 3.189 and − 3.381, respectively. The docking results revealed that the synthesized hybrids exhibited potent anti-dengue activity among which compounds SKYf, SKYd, SKYc and SKYe were found to be the best ones with docking scores of − 4.014, − 3.964, − 3.905 and − 3.889. In summary, we discovered 4-thiazolidinone coumarin derivatives as a new scaffold that may eventually yield useful compounds in the treatment of bacterial and viral infections.Electronic supplementary materialThe online version of this article (10.1186/s13065-018-0435-0) contains supplementary material, which is available to authorized users.