Skip to main page content
U.S. flag

An official website of the United States government

Dot gov

The .gov means it’s official.
Federal government websites often end in .gov or .mil. Before sharing sensitive information, make sure you’re on a federal government site.

Https

The site is secure.
The https:// ensures that you are connecting to the official website and that any information you provide is encrypted and transmitted securely.

Access keys NCBI Homepage MyNCBI Homepage Main Content Main Navigation
. 2021 Feb 24;26(5):1205.
doi: 10.3390/molecules26051205.

Quinoline Functionalized Schiff Base Silver (I) Complexes: Interactions with Biomolecules and In Vitro Cytotoxicity, Antioxidant and Antimicrobial Activities

Adesola A Adeleke  1   2 , Sizwe J Zamisa  3 , Md Shahidul Islam  4 , Kolawole Olofinsan  4 , Veronica F Salau  4 , Chunderika Mocktar  5 , Bernard Omondi  1
Affiliations

Quinoline Functionalized Schiff Base Silver (I) Complexes: Interactions with Biomolecules and In Vitro Cytotoxicity, Antioxidant and Antimicrobial Activities

Adesola A Adeleke et al. Molecules. .

Abstract

A series of fifteen silver (I) quinoline complexes Q1-Q15 have been synthesized and studied for their biological activities. Q1-Q15 were synthesized from the reactions of quinolinyl Schiff base derivatives L1-L5 (obtained by condensing 2-quinolinecarboxaldehyde with various aniline derivatives) with AgNO3, AgClO4 and AgCF3SO3. Q1-Q15 were characterized by various spectroscopic techniques and the structures of [Ag(L1)2]NO3Q1, [Ag(L1)2]ClO4Q6, [Ag(L2)2]ClO4Q7, [Ag(L2)2]CF3SO3Q12 and [Ag(L4)2]CF3SO3Q14 were unequivocally determined by single crystal X-ray diffraction analysis. In vitro antimicrobial tests against Gram-positive and Gram-negative bacteria revealed the influence of structure and anion on the complexes' moderate to excellent antibacterial activity. In vitro antioxidant activities of the complexes showed their good radical scavenging activity in ferric reducing antioxidant power (FRAP). Complexes with the fluorine substituent or the thiophene or benzothiazole moieties are more potent with IC50 between 0.95 and 2.22 mg/mL than the standard used, ascorbic acid (2.68 mg/mL). The compounds showed a strong binding affinity with calf thymus-DNA via an intercalation mode and protein through a static quenching mechanism. Cytotoxicity activity was examined against three carcinoma cell lines (HELA, MDA-MB231, and SHSY5Y). [Ag(L2)2]ClO4Q7 with a benzothiazole moiety and [Ag(L4)2]ClO4Q9 with a methyl substituent had excellent cytotoxicity against HELA cells.

Keywords: Ag(I); BSA; CT-DNA; antimicrobial; antioxidant; cytotoxicity; quinolines.

PubMed Disclaimer

Conflict of interest statement

The authors declare no conflict of interest.

Figures

Scheme 1
Scheme 1
Synthesis of Q1–Q15 under constant magnetic stirring in anhydrous ethanol.
Figure 1
Figure 1
(a): Electronic absorption spectra of L1 and Complexes Q1, Q6 and Q11, (b) Electronic absorption spectra of L2 and Complexes Q2, Q7 and Q12, (c) Electronic absorption spectra of L3 and Complexes Q3, Q8 and Q13, (d) Electronic absorption spectra of L4 and Complexes Q4, Q9 and Q14, (e) Electronic absorption spectra of L5 and Complexes Q5, Q10 and Q15.
Figure 1
Figure 1
(a): Electronic absorption spectra of L1 and Complexes Q1, Q6 and Q11, (b) Electronic absorption spectra of L2 and Complexes Q2, Q7 and Q12, (c) Electronic absorption spectra of L3 and Complexes Q3, Q8 and Q13, (d) Electronic absorption spectra of L4 and Complexes Q4, Q9 and Q14, (e) Electronic absorption spectra of L5 and Complexes Q5, Q10 and Q15.
Figure 2
Figure 2
The ORTEP diagrams showing the atom numbering scheme with the thermal ellipsoids drawn at the 50% probability level for molecule of complexes (a) Q1, (b) Q6, (c) Q7, (d) Q12, and (e) Q14. Hydrogen atoms have been omitted for clarity.
Figure 2
Figure 2
The ORTEP diagrams showing the atom numbering scheme with the thermal ellipsoids drawn at the 50% probability level for molecule of complexes (a) Q1, (b) Q6, (c) Q7, (d) Q12, and (e) Q14. Hydrogen atoms have been omitted for clarity.
Figure 3
Figure 3
(a) Minimum inhibitory concentration (µg/mL) of L1–L5 silver(I) complexes with nitrate as counter anion, (b) Minimum inhibitory concentration (µg/mL) of L1–L5 silver(I) complexes with perchlorate as counter anion, and (c) Minimum inhibitory concentration (µg/mL) of L1–L5 silver(I) complexes with triflate as counter anion.
Figure 3
Figure 3
(a) Minimum inhibitory concentration (µg/mL) of L1–L5 silver(I) complexes with nitrate as counter anion, (b) Minimum inhibitory concentration (µg/mL) of L1–L5 silver(I) complexes with perchlorate as counter anion, and (c) Minimum inhibitory concentration (µg/mL) of L1–L5 silver(I) complexes with triflate as counter anion.
Figure 4
Figure 4
FRAP % free radical scavenging vs. Concentration (mg/mL) of complexes Q1–Q15, silver nitrate, silver perchlorate, silver triflate, and Ascorbic Acid. AgN = silver nitrate, AgC = silver perchlorate, AgF = silver triflate and As = Ascorbic acid values represent mean ± standard deviation (n = 3). a–f Different alphabets over the bars for a given concentration for each complex represent significant difference (Tukey′s-HSD multiple range post hoc test, p < 0.05).
Figure 5
Figure 5
(a) Electronic Absorption Spectra of complex Q8 at 3.0 × 106 M in the absence (dashed line) and the presence of different concentrations of CT-DNA (0–3.0 × 105 M) at 303 nm λmax. (inset) A Stern–Volmer plot of Q8 interaction with CT- DNA. (b) Fluorescence spectra of EB-CT-DNA in the absence (dashed line) and the presence of a different concentration of complex Q8. (inset) The stern–Volmer plot of Q8 interaction with EB-CT- DNA. (c) Stern–Volmer plot of Complexes Q1–Q15 interaction with EB-CT- DNA. (d) The double-logarithmic plot of Complex Q10.
Figure 5
Figure 5
(a) Electronic Absorption Spectra of complex Q8 at 3.0 × 106 M in the absence (dashed line) and the presence of different concentrations of CT-DNA (0–3.0 × 105 M) at 303 nm λmax. (inset) A Stern–Volmer plot of Q8 interaction with CT- DNA. (b) Fluorescence spectra of EB-CT-DNA in the absence (dashed line) and the presence of a different concentration of complex Q8. (inset) The stern–Volmer plot of Q8 interaction with EB-CT- DNA. (c) Stern–Volmer plot of Complexes Q1–Q15 interaction with EB-CT- DNA. (d) The double-logarithmic plot of Complex Q10.
Figure 6
Figure 6
(a) Electronic Absorption Spectra of BSA in the absence (dashed line) and the presence of different concentrations of complexes Q12. (inset) Plot of 1/(Aₒ − A) vs. 1/[Complex] × 10−4 M−1. (b) Fluorescence emission spectra of BSA in the absence(dashed line) and the presence of a different concentration of complex Q11. Inset: A Stern–Volmer plot of the interaction of Q11 with BSA. (c) The double-logarithmic plot of BSA–Complex Q6 interactions.
Figure 6
Figure 6
(a) Electronic Absorption Spectra of BSA in the absence (dashed line) and the presence of different concentrations of complexes Q12. (inset) Plot of 1/(Aₒ − A) vs. 1/[Complex] × 10−4 M−1. (b) Fluorescence emission spectra of BSA in the absence(dashed line) and the presence of a different concentration of complex Q11. Inset: A Stern–Volmer plot of the interaction of Q11 with BSA. (c) The double-logarithmic plot of BSA–Complex Q6 interactions.
See this image and copyright information in PMC

Similar articles

See all similar articles

Cited by

See all "Cited by" articles

References

    1. Bine F.K., Nkungli N.K., Numbonui T.S., Numbonui Ghogomu J. Structural Properties and Reactive Site Selectivity of Some Transition Metal Complexes of 2,2’(1E,1’E)-(ethane-1,2-diylbis(azan-1-yl-1-ylidene))bis(phenylmethan-1-yl-1-yli dene)dibenzoic Acid: DFT, Conceptual DFT, QTAIM, and MEP Studies. Bioinorg. Chem. Appl. 2018;2018:4510648. doi: 10.1155/2018/4510648. - DOI - PMC - PubMed
    1. Manna A.K., Rout K., Chowdhury S., Patra G.K. A dual-mode highly selective and sensitive Schiff base chemosensor for fluorescent colorimetric detection of Ni(2+) and colorimetric detection of Cu(2) Photochem. Photobiol. Sci. 2019;18:1512–1525. doi: 10.1039/C9PP00114J. - DOI - PubMed
    1. Khandar A.A., Afkhami F.A., Hosseini-Yazdi S.A., White J.M., Kassel S., Dougherty W.G., Lipkowski J., van Derveer D., Giester G., Costantino F. Anion influence in the structural diversity of cadmium coordination polymers constructed from a pyridine based Schiff base ligand. Inorg. Chim. Acta. 2015;427:87–96. doi: 10.1016/j.ica.2014.11.028. - DOI
    1. Kajal A., Bala S., Kamboj S., Sharma N., Saini V. Schiff Bases: A Versatile Pharmacophore. J. Catal. 2013;2013:1–14. doi: 10.1155/2013/893512. - DOI
    1. Garrido Montalban A. Quinolines and Isoquinolines. Heterocycl. Nat. Prod. Synth. 2011:299–339. doi: 10.1002/9783527634880.ch9. - DOI

MeSH terms

LinkOut - more resources